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Open AccessArticle

A Green Synthesis of CoFe₂O₄ Decorated ZIF-8 Composite for Electrochemical Oxygen Evolution

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Atanu Panda

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Hang-Kyu Cho

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Hansang Kim

Int. J. Mol. Sci. 2023, 24(11), 9585; https://doi.org/10.3390/ijms24119585 - 31 May 2023

Viewed by 203

Abstract

Low-cost, sustainable hydrogen production requires noble metal-free electrocatalysts for water splitting. In this study, we prepared zeolitic imidazolate frameworks (ZIF) decorated with CoFe₂O₄ spinel nanoparticles as active catalysts for oxygen evolution reaction (OER). The CoFe₂O₄ nanoparticles were [...] Read more.

Low-cost, sustainable hydrogen production requires noble metal-free electrocatalysts for water splitting. In this study, we prepared zeolitic imidazolate frameworks (ZIF) decorated with CoFe₂O₄ spinel nanoparticles as active catalysts for oxygen evolution reaction (OER). The CoFe₂O₄ nanoparticles were synthesized by converting agricultural bio-waste (potato peel extract) into economically valuable electrode materials. The biogenic CoFe₂O₄ composite showed an overpotential of 370 mV at a current density of 10 mA cm⁻² and a low Tafel slope of 283 mV dec⁻¹, whereas the ZIF@CoFe₂O₄ composite prepared using an in situ hydrothermal method showed an overpotential of 105 mV at 10 mA cm⁻² and a low Tafel slope of 43 mV dec⁻¹ in a 1 M KOH medium. The results demonstrated an exciting prospect of high-performance noble metal-free electrocatalysts for low-cost, high-efficiency, and sustainable hydrogen production. Full article

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Open AccessArticle

Investigating the Theranostic Potential of Graphene Quantum Dots in Alzheimer’s Disease

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Max Walton-Raaby

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Riley Woods

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Subha Kalyaanamoorthy

Int. J. Mol. Sci. 2023, 24(11), 9476; https://doi.org/10.3390/ijms24119476 - 30 May 2023

Viewed by 382

Abstract

Alzheimer’s disease (AD) is one of the leading causes of death worldwide, with no definitive diagnosis or known cure. The aggregation of Tau protein into neurofibrillary tangles (NFTs), which contain straight filaments (SFs) and paired helical filaments (PHFs), is a major hallmark of [...] Read more.

Alzheimer’s disease (AD) is one of the leading causes of death worldwide, with no definitive diagnosis or known cure. The aggregation of Tau protein into neurofibrillary tangles (NFTs), which contain straight filaments (SFs) and paired helical filaments (PHFs), is a major hallmark of AD. Graphene quantum dots (GQDs) are a type of nanomaterial that combat many of the small-molecule therapeutic challenges in AD and have shown promise in similar pathologies. In this study, two sizes of GQDs, GQD7 and GQD28, were docked to various forms of Tau monomers, SFs, and PHFs. From the favorable docked poses, we simulated each system for at least 300 ns and calculated the free energies of binding. We observed a clear preference for GQD28 in the PHF6 (³⁰⁶VQIVYK³¹¹) pathological hexapeptide region of monomeric Tau, while GQD7 targeted both the PHF6 and PHF6* (²⁷⁵VQIINK²⁸⁰) pathological hexapeptide regions. In SFs, GQD28 had a high affinity for a binding site that is available in AD but not in other common tauopathies, while GQD7 behaved promiscuously. In PHFs, GQD28 interacted strongly near the protofibril interface at the putative disaggregation site for epigallocatechin-3-gallate, and GQD7 largely interacted with PHF6. Our analyses revealed several key GQD binding sites that may be used for detecting, preventing, and disassembling the Tau aggregates in AD. Full article

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Open AccessArticle

Study of the Electronic Interaction between NiO and Short Polythiophene Chains towards Solar Photon Harvesting

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Guillermo Carbajal-Franco

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María Fernanda Márquez-Quintana

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Hugo Rojas-Chávez

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Alan Miralrio

Int. J. Mol. Sci. 2023, 24(11), 9109; https://doi.org/10.3390/ijms24119109 - 23 May 2023

Viewed by 457

Abstract

The sustainable production of energy is a field of interest to which a new requirement is now imposed: the need to be respectful of the environment. New materials and techniques are being developed, but environmental concerns impose the necessity of keeping research active [...] Read more.

The sustainable production of energy is a field of interest to which a new requirement is now imposed: the need to be respectful of the environment. New materials and techniques are being developed, but environmental concerns impose the necessity of keeping research active towards the development of green energy. For this reason, we present the study of short polythiophene (PTh) chains (three and five monomers) and their interaction with nickel oxide, looking for properties related to solar photon harvesting in order to produce electricity. The models of the molecules were developed, and the calculations were performed with an M11-L meta-GGA functional, specially developed for electronic structure calculations. The theoretical explorations demonstrated that the geometry of the PTh molecules suffer little distortion when interacting with the NiO molecule. The calculated value of E_g lies between 2.500 and 0.412 eV for a three-ring PTh chain and between 1.944 and 0.556 eV for a five-ring PTh chain. The chemical parameters indicated that, depending on the geometry of the system, the chemical potential varies from 81.27 to 102.38 kcal/mol and the highest amount of electronic charge varies from −2.94 to 21.56 a.u. for three-monomer systems. For five-monomer systems, the values lie within similar ranges as those of the three-monomer systems. The Partial Density of States (PDOS) showed that the valence and conduction electronic bands were composed of states in the NiO and PTh rings, except for a system where there was a non-bonding interaction. Full article

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Open AccessArticle

Near-Infrared Light-Activated Mesoporous Polydopamine for Temporomandibular Joint Osteoarthritis Combined Photothermal-Chemo Therapy

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Int. J. Mol. Sci. 2023, 24(10), 9055; https://doi.org/10.3390/ijms24109055 - 21 May 2023

Viewed by 456

Abstract

The treatments generally employed for temporomandibular joint osteoarthritis (TMJOA) involve physical therapy and chemotherapy, etc., whose therapeutic efficacies are impaired by the side effects and suboptimal stimulus responsiveness. Although the intra-articular drug delivery system (DDS) has shown effectiveness in addressing osteoarthritis, there is [...] Read more.

The treatments generally employed for temporomandibular joint osteoarthritis (TMJOA) involve physical therapy and chemotherapy, etc., whose therapeutic efficacies are impaired by the side effects and suboptimal stimulus responsiveness. Although the intra-articular drug delivery system (DDS) has shown effectiveness in addressing osteoarthritis, there is currently little reported research regarding the use of stimuli-responsive DDS in managing TMJOA. Herein, we prepared a novel near-infrared (NIR) light-sensitive DDS (DS-TD/MPDA) by using mesoporous polydopamine nanospheres (MPDA) as NIR responders and drug carriers; diclofenac sodium (DS) as the anti-inflammatory medication; and 1-tetradecanol (TD) with a phase-inversion temperature of 39 °C as the drug administrator. Upon exposure to 808 nm NIR laser, DS-TD/MPDA could raise the temperature up to the melting point of TD through photothermal conversion, and intelligently trigger DS release. The resultant nanospheres exhibited an excellent photothermal effect and effectively controlled the release of DS through laser irradiation to accommodate the multifunctional therapeutic effect. More importantly, the biological evaluation of DS-TD/MPDA for TMJOA treatment was also performed for the first time. The experiments’ results demonstrated that DS-TD/MPDA displayed a good biocompatibility in vitro and in vivo during metabolism. After injection into the TMJ of rats afflicted with TMJOA induced by unilateral anterior crossbite for 14 days, DS-TD/MPDA could alleviate the deterioration of TMJ cartilage, thus ameliorating osteoarthritis. Therefore, DS-TD/MPDA could be a promising candidate for photothermal-chemotherapy for TMJOA. Full article

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Open AccessArticle

Ru(II) Oxygen Sensors for Co(III) Complexes and Amphotericin B Antifungal Activity Detection by Phosphorescence Optical Respirometry

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Katarzyna Turecka

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Agnieszka Chylewska

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Aleksandra M. Dąbrowska

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Rafał Hałasa

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Czesława Orlewska

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Krzysztof Waleron

Int. J. Mol. Sci. 2023, 24(10), 8744; https://doi.org/10.3390/ijms24108744 - 14 May 2023

Cited by 1 | Viewed by 596

Abstract

The measurement of oxygen consumption is an important element in the understanding of an organism’s metabolic state. Oxygen is also a phosphorescence quencher, which allows the evaluation of phosphorescence emitted by oxygen sensors. Two Ru(II)-based oxygen-sensitive sensors were used to study the effect [...] Read more.

The measurement of oxygen consumption is an important element in the understanding of an organism’s metabolic state. Oxygen is also a phosphorescence quencher, which allows the evaluation of phosphorescence emitted by oxygen sensors. Two Ru(II)-based oxygen-sensitive sensors were used to study the effect of chemical compounds [(1) = [CoCl₂(dap)₂]Cl, and (2) = [CoCl₂(en)₂]Cl (AmB = amphotericin B) against reference and clinical strains of Candida albicans. The tris-[(4,7-diphenyl-1,10-phenanthroline)ruthenium(II)] chloride ([Ru(DPP)₃]Cl₂) (Box) adsorbed onto the Davisil^TM silica gel was embedded in the silicone rubber Lactite NuvaSil^® 5091 and the coating on the bottom of 96-well plates. The water-soluble oxygen sensor (BsOx = tris-[(4,7-diphenyl-1,10-phenanthrolinedisulphonic acid disodium)ruthenium(II)] chloride ‘x’ hydrate = {Ru[DPP(SO₃Na)₂]₃}Cl₂ = water molecules were omitted in the BsOx formula) was synthesized and characterized by RP-UHPLC, LCMS, MALDI, elemental analysis, ATR, UV-Vis, ¹H NMR, and TG/IR techniques. The microbiological studies were performed in the environment of RPMI broth and blood serum. Both Ru(II)-based sensors turned out to be useful in the study of the activity of Co(III) complexes and the commercial antifungal drug amphotericin B. In addition, a new activity of the oxygen sensor, the soluble Ru(II) complex BsOx, was demonstrated, which is a mixture with amphotericin B that caused a significant increase in its antifungal activity. Thus, it is also possible to demonstrate the synergistic effect of compounds active against the microorganisms under study. Full article

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Open AccessReview

Deep Eutectic Solvents Comprising Organic Acids and Their Application in (Bio)Medicine

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Int. J. Mol. Sci. 2023, 24(10), 8492; https://doi.org/10.3390/ijms24108492 - 09 May 2023

Viewed by 789

Abstract

Over the last years, we observed a significant increase in the number of published studies that focus on the synthesis and characterization of deep eutectic solvents (DESs). These materials are of particular interest mainly due to their physical and chemical stability, low vapor [...] Read more.

Over the last years, we observed a significant increase in the number of published studies that focus on the synthesis and characterization of deep eutectic solvents (DESs). These materials are of particular interest mainly due to their physical and chemical stability, low vapor pressure, ease of synthesis, and the possibility of tailoring their properties through dilution or change of the ratio of parent substances (PS). DESs, considered as one of the greenest families of solvents, are used in many fields, such as organic synthesis, (bio)catalysis, electrochemistry, and (bio)medicine. DESs applications have already been reported in various review articles. However, these reports mainly described these components’ basics and general properties without focusing on the particular, PS-wise, group of DESs. Many DESs investigated for potential (bio)medical applications comprise organic acids. However, due to the different aims of the reported studies, many of these substances have not yet been investigated thoroughly, which makes it challenging for the field to move forward. Herein, we propose distinguishing DESs comprising organic acids (OA-DESs) as a specific group derived from natural deep eutectic solvents (NADESs). This review aims to highlight and compare the applications of OA-DESs as antimicrobial agents and drug delivery enhancers—two essential fields in (bio)medical studies where DESs have already been implemented and proven their potential. From the survey of the literature data, it is evident that OA-DESs represent an excellent type of DESs for specific biomedical applications, owing to their negligible cytotoxicity, fulfilling the rules of green chemistry and being generally effective as drug delivery enhancers and antimicrobial agents. The main focus is on the most intriguing examples and (where possible) application-based comparison of particular groups of OA-DESs. This should highlight the importance of OA-DESs and give valuable clues on the direction the field can take. Full article

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Open AccessArticle

Domain Localization by Graphene Oxide in Supported Lipid Bilayers

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Ryugo Tero

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Yoshi Hagiwara

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Shun Saito

Int. J. Mol. Sci. 2023, 24(9), 7999; https://doi.org/10.3390/ijms24097999 - 28 Apr 2023

Viewed by 528

Abstract

The gel-phase domains in a binary supported lipid bilayer (SLB) comprising dioleoylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC) were localized on graphene oxide (GO) deposited on a SiO₂/Si substrate. We investigated the distribution of the gel-phase domains and the liquid crystalline (L_α [...] Read more.

The gel-phase domains in a binary supported lipid bilayer (SLB) comprising dioleoylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC) were localized on graphene oxide (GO) deposited on a SiO₂/Si substrate. We investigated the distribution of the gel-phase domains and the liquid crystalline (L_α) phase regions in DOPC+DPPC-SLB on thermally oxidized SiO₂/Si substrates with GO flakes to understand the mechanism of the domain localization on GO. Fluorescence microscopy and atomic force microscopy revealed that the gel-phase domains preferably distributed on GO flakes, whereas the fraction of the L_α-phase increased on the bare SiO₂ surface which was not covered with the GO flakes. The gel-phase domain was condensed on GO more effectively at the lower cooling rate. We propose that nucleation of the gel-phase domain preferentially occurred on GO, whose surface has amphiphilic property, during the gel-phase domain formation. The domains of the liquid ordered (L_o) phase were also condensed on GO in a ternary bilayer containing cholesterol that was phase-separated to the L_o phase and the liquid disordered phase. Rigid domains segregates on GO during their formation process, leaving fluid components to the surrounding region of GO. Full article

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Open AccessArticle

The Encapsulation of Natural Organic Dyes on TiO₂ for Photochromism Control

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Int. J. Mol. Sci. 2023, 24(9), 7860; https://doi.org/10.3390/ijms24097860 - 26 Apr 2023

Viewed by 696

Abstract

Titanium dioxide (TiO₂) plays a pivotal role in photocatalytic reactions and holds great promise for the cosmetic and paint industries due to its white color and high refractive index. However, the original color of TiO₂ changes gradually to blue or [...] Read more.

Titanium dioxide (TiO₂) plays a pivotal role in photocatalytic reactions and holds great promise for the cosmetic and paint industries due to its white color and high refractive index. However, the original color of TiO₂ changes gradually to blue or yellow with UV irradiation, which affects its color realization. We encapsulated TiO₂ with several natural organic dye compounds, including purpurin, curcumin, and safflower, to control its photochromism and realize a range of different colors. The chemical reaction between TiO₂ and dyes based on their functional group was investigated, and the light absorption was tested via FTIR and UV–Vis spectroscopy. The changes in morphology and size distribution additionally supported their successful encapsulation. The discoloration after UV irradiation was evaluated by measuring the color difference (ΔE) of control TiO₂ and dye encapsulated TiO₂. The unique structure utilized natural dyes to preserve photochromism based on the physical barrier and automatically controlled the electronic transition of core TiO₂. In particular, the color difference values of purpurin and curcumin were 4.05 and 3.76, which is lower than the 5.36 of the control TiO₂. Dye encapsulated TiO₂ was manipulated into lipstick to verify its color realization and retention. Full article

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Open AccessArticle

Molecule Clustering Dynamics in the Molecular Doping Process of Si(111) with Diethyl-propyl-phosphonate

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Mattia Pizzone

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Maria Grazia Grimaldi

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Int. J. Mol. Sci. 2023, 24(8), 6877; https://doi.org/10.3390/ijms24086877 - 07 Apr 2023

Viewed by 946

Abstract

The molecular doping (MD) process is based on the deposition of dopant-containing molecules over the surface of a semiconductor substrate, followed by the thermal diffusion step. Previous studies suggest that, during the deposition, the molecules nucleate clusters, and at prolonged deposition times, they [...] Read more.

The molecular doping (MD) process is based on the deposition of dopant-containing molecules over the surface of a semiconductor substrate, followed by the thermal diffusion step. Previous studies suggest that, during the deposition, the molecules nucleate clusters, and at prolonged deposition times, they grow into self-assembled layers on the sample to be doped. Little is known about the influence of nucleation kinetics on the final properties of these layers and how they change when we modify the solution properties. In this work, we examine the nucleation rate and the molecular surface coverage kinetics of diethyl-propyl phosphonate on silicon at different solution concentrations and how these conditions influence the final electrical properties of the doped samples. We present a high-resolution morphological characterization of the as-deposited molecules together with the electrical results of the final doped samples. The experimental results show a non-obvious behavior, explained through understanding of the competition between the molecules’ physisorption and chemisorption mechanisms. As a consequence, due to the deeper knowledge of the deposition phase, a finer tuning of the conductive properties of MD-doped samples is achieved. Full article

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Open AccessArticle

Bioglues Based on an Elastin-Like Recombinamer: Effect of Tannic Acid as an Additive on Tissue Adhesion and Cytocompatibility

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Alp Sarisoy

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Sergio Acosta

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José Carlos Rodríguez-Cabello

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Phillip Czichowski

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Alexander Kopp

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Stefan Jockenhoevel

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Alicia Fernández-Colino

Int. J. Mol. Sci. 2023, 24(7), 6776; https://doi.org/10.3390/ijms24076776 - 05 Apr 2023

Viewed by 1121

Abstract

More than 260 million surgical procedures are performed worldwide each year. Although sutures and staples are widely used to reconnect tissues, they can cause further damage and increase the risk of infection. Bioadhesives have been proposed as an alternative to reconnect tissues. However, [...] Read more.

More than 260 million surgical procedures are performed worldwide each year. Although sutures and staples are widely used to reconnect tissues, they can cause further damage and increase the risk of infection. Bioadhesives have been proposed as an alternative to reconnect tissues. However, clinical adhesives that combine strong adhesion with cytocompatibility have yet to be developed. In this study, we explored the production of adhesives based on protein-engineered polymers bioinspired by the sequence of elastin (i.e., elastin-like recombinamers, ELRs). We hypothesized that the combination of polyphenols (i.e., tannic acid, TA) and ELRs would produce an adhesive coacervate (ELR+TA), as reported for other protein polymers such as silk fibroin (SF). Notably, the adhesion of ELR alone surpassed that of ELR+TA. Indeed, ELR alone achieved adhesive strengths of 88.8 ± 33.2 kPa and 17.0 ± 2.0 kPa on porcine bone and skin tissues, respectively. This surprising result led us to explore a multicomponent bioadhesive to encompass the complementary roles of elastin (mimicked here by ELR) and silk fibroin (SF), and subsequently mirror more closely the multicomponent nature of the extracellular matrix. Tensile testing showed that ELR+SF achieved an adhesive strength of 123.3 ± 60.2 kPa on porcine bone and excellent cytocompatibility. To express this in a more visual and intuitive way, a small surface of only 2.5 cm² was able to lift at least 2 kg of weight. This opens the door for further studies focusing on the ability of protein-engineered polymers to adhere to biological tissues without further chemical modification for applications in tissue engineering. Full article

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Open AccessArticle

High-Order Harmonics Generation in MoS₂ Transition Metal Dichalcogenides: Effect of Nickel and Carbon Nanotube Dopants

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Mottamchetty Venkatesh

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Int. J. Mol. Sci. 2023, 24(7), 6540; https://doi.org/10.3390/ijms24076540 - 31 Mar 2023

Viewed by 874

Abstract

The transition metal dichalcogenides have instigated a lot of interest as harmonic generators due to their exceptional nonlinear optical properties. Here, the molybdenum disulfide (MoS₂) molecular structures with dopants being in a plasma state are used to demonstrate the generation of [...] Read more.

The transition metal dichalcogenides have instigated a lot of interest as harmonic generators due to their exceptional nonlinear optical properties. Here, the molybdenum disulfide (MoS₂) molecular structures with dopants being in a plasma state are used to demonstrate the generation of intense high-order harmonics. The MoS₂ nanoflakes and nickel-doped MoS₂ nanoflakes produced stronger harmonics with higher cut-offs compared with Mo bulk and MoS₂ bulk. Conversely, the MoS₂ with nickel nanoparticles and carbon nanotubes (MoS₂-NiCNT) produced weaker coherent XUV emissions than other materials, which is attributed to the influence of phase mismatch. The influence of heating and driving pulse intensities on the harmonic yield and cut-off energies are investigated in MoS₂ molecular structures. The enhanced coherent extreme ultraviolet emission at ~32 nm (38 eV) due to the 4p-4d resonant transitions is obtained from all aforementioned molecular structures, except for MoS₂-NiCNT. Full article

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Open AccessArticle

Microstructural and Mechanical Characterization of Al Nanocomposites Using GCNs as a Reinforcement Fabricated by Induction Sintering

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Verónica Gallegos Orozco

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Audel Santos Beltrán

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Miriam Santos Beltrán

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Hansel Medrano Prieto

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Carmen Gallegos Orozco

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Ivanovich Estrada Guel

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Roberto Martínez Sánchez

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José Manuel Mendoza Duarte

Int. J. Mol. Sci. 2023, 24(6), 5558; https://doi.org/10.3390/ijms24065558 - 14 Mar 2023

Viewed by 581

Abstract

High-energy ball milling is a process suitable for producing composite powders whose achieved microstructure can be controlled by the processing parameters. Through this technique, it is possible to obtain a homogeneous distribution of reinforced material into a ductile metal matrix. In this work, [...] Read more.

High-energy ball milling is a process suitable for producing composite powders whose achieved microstructure can be controlled by the processing parameters. Through this technique, it is possible to obtain a homogeneous distribution of reinforced material into a ductile metal matrix. In this work, some Al/CGNs nanocomposites were fabricated through a high-energy ball mill to disperse nanostructured graphite reinforcements produced in situ in the Al matrix. To retain the dispersed CGNs in the Al matrix, avoiding the precipitation of the Al₄C₃ phase during sintering, the high-frequency induction sintering (HFIS) method was used, which allows rapid heating rates. For comparative purposes, samples in the green and sintered state processed in a conventional electric furnace (CFS) were used. Microhardness testing was used to evaluate the effectiveness of the reinforcement in samples under different processing conditions. Structural analyses were carried out through an X-ray diffractometer coupled with a convolutional multiple whole profile (CMWP) fitting program to determine the crystallite size and dislocation density; both strengthening contributions were calculated using the Langford–Cohen and Taylor equations. According to the results, the CGNs dispersed in the Al matrix played an important role in the reinforcement of the Al matrix, promoting the increase in the dislocation density during the milling process. The strengthening contribution of the dislocation density was ~50% of the total hardening value, while the contribution by dispersion of CGNs was ~22% in samples with 3 wt. % C and sintered by the HFIS method. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to analyze the morphology, size, and distribution of phases present in the Al matrix. From the analyses carried out in AFM (topography and phase images), the CGNs are located mainly around crystallites and present height profiles of 1.6 to 2 nm. Full article

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Open AccessArticle

Application of Pyrolysis for the Evaluation of Organic Compounds in Medical Plastic Waste Generated in the City of Cartagena-Colombia Applying TG-GC/MS

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Joaquín Hernandez-Fernandez

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Henry Lambis

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Ricardo Vivas Reyes

Int. J. Mol. Sci. 2023, 24(6), 5397; https://doi.org/10.3390/ijms24065397 - 11 Mar 2023

Viewed by 1362

Abstract

In this study, the thermal degradation and pyrolysis of hospital plastic waste consisting of polyethylene (PE), polystyrene (PS), and polypropylene (PP) were investigated using TG-GC/MS. The identified molecules with the functional groups of alkanes, alkenes, alkynes, alcohols, aromatics, phenols, CO and CO₂ [...] Read more.

In this study, the thermal degradation and pyrolysis of hospital plastic waste consisting of polyethylene (PE), polystyrene (PS), and polypropylene (PP) were investigated using TG-GC/MS. The identified molecules with the functional groups of alkanes, alkenes, alkynes, alcohols, aromatics, phenols, CO and CO₂ were found in the gas stream from pyrolysis and oxidation, and are chemical structures with derivatives of aromatic rings. They are mainly related to the degradation of PS hospital waste, and the alkanes and alkenes groups originate mainly from PP and PE-based medical waste. The pyrolysis of this hospital waste did not show the presence of derivatives of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, which is an advantage over classical incineration methodologies. CO, CO₂, phenol, acetic acid and benzoic acid concentrations were higher in the gases from the oxidative degradation than in those generated in the pyrolysis with helium. In this article, we propose different pathways of reaction mechanisms that allow us to explain the presence of molecules with other functional groups, such as alkanes, alkenes, carboxylic acids, alcohols, aromatics and permanent gases. Full article

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Open AccessCommunication

Aptamers as Novel Binding Molecules on an Antimicrobial Peptide-Armored Composite Hydrogel Wound Dressing for Specific Removal and Efficient Eradication of Pseudomonas aeruginosa

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Christopher V. Synatschke

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Kay-Eberhard Gottschalk

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Int. J. Mol. Sci. 2023, 24(5), 4800; https://doi.org/10.3390/ijms24054800 - 02 Mar 2023

Viewed by 2910

Abstract

Here we present for the first time a potential wound dressing material implementing aptamers as binding entities to remove pathogenic cells from newly contaminated surfaces of wound matrix-mimicking collagen gels. The model pathogen in this study was the Gram-negative opportunistic bacterium Pseudomonas aeruginosa [...] Read more.

Here we present for the first time a potential wound dressing material implementing aptamers as binding entities to remove pathogenic cells from newly contaminated surfaces of wound matrix-mimicking collagen gels. The model pathogen in this study was the Gram-negative opportunistic bacterium Pseudomonas aeruginosa, which represents a considerable health threat in hospital environments as a cause of severe infections of burn or post-surgery wounds. A two-layered hydrogel composite material was constructed based on an established eight-membered focused anti-P. aeruginosa polyclonal aptamer library, which was chemically crosslinked to the material surface to form a trapping zone for efficient binding of the pathogen. A drug-loaded zone of the composite released the C14R antimicrobial peptide to deliver it directly to the bound pathogenic cells. We demonstrate that this material combining aptamer-mediated affinity and peptide-dependent pathogen eradication can quantitatively remove bacterial cells from the “wound” surface, and we show that the surface-trapped bacteria are completely killed. The drug delivery function of the composite thus represents an extra safeguarding property and thus probably one of the most important additional advances of a next-generation or smart wound dressing ensuring the complete removal and/or eradication of the pathogen of a freshly infected wound. Full article

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Open AccessArticle

Intracellular Nitric Oxide and cAMP Are Involved in Cellulolytic Enzyme Production in Neurospora crassa

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Nan-Nan Yu

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Wirinthip Ketya

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Gyungsoon Park

Int. J. Mol. Sci. 2023, 24(5), 4503; https://doi.org/10.3390/ijms24054503 - 24 Feb 2023

Viewed by 726

Abstract

Although molecular regulation of cellulolytic enzyme production in filamentous fungi has been actively explored, the underlying signaling processes in fungal cells are still not clearly understood. In this study, the molecular signaling mechanism regulating cellulase production in Neurospora crassa was investigated. We found [...] Read more.

Although molecular regulation of cellulolytic enzyme production in filamentous fungi has been actively explored, the underlying signaling processes in fungal cells are still not clearly understood. In this study, the molecular signaling mechanism regulating cellulase production in Neurospora crassa was investigated. We found that the transcription and extracellular cellulolytic activity of four cellulolytic enzymes (cbh1, gh6-2, gh5-1, and gh3-4) increased in Avicel (microcrystalline cellulose) medium. Intracellular nitric oxide (NO) and reactive oxygen species (ROS) detected by fluorescent dyes were observed in larger areas of fungal hyphae grown in Avicel medium compared to those grown in glucose medium. The transcription of the four cellulolytic enzyme genes in fungal hyphae grown in Avicel medium was significantly decreased and increased after NO was intracellularly removed and extracellularly added, respectively. Furthermore, we found that the cyclic AMP (cAMP) level in fungal cells was significantly decreased after intracellular NO removal, and the addition of cAMP could enhance cellulolytic enzyme activity. Taken together, our data suggest that the increase in intracellular NO in response to cellulose in media may have promoted the transcription of cellulolytic enzymes and participated in the elevation of intracellular cAMP, eventually leading to improved extracellular cellulolytic enzyme activity. Full article

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Open AccessArticle

Significance of MnO₂ Type and Solution Parameters in Manganese Removal from Water Solution

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Magdalena M. Michel

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Mostafa Azizi

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Dorota Mirosław-Świątek

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Lidia Reczek

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Bogumił Cieniek

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Eleonora Sočo

Int. J. Mol. Sci. 2023, 24(5), 4448; https://doi.org/10.3390/ijms24054448 - 23 Feb 2023

Viewed by 781

Abstract

A very low concentration of manganese (Mn) in water is a critical issue for municipal and industrial water supply systems. Mn removal technology is based on the use of manganese oxides (MnO_x), especially manganese dioxide (MnO₂) polymorphs, under different [...] Read more.

A very low concentration of manganese (Mn) in water is a critical issue for municipal and industrial water supply systems. Mn removal technology is based on the use of manganese oxides (MnO_x), especially manganese dioxide (MnO₂) polymorphs, under different conditions of pH and ionic strength (water salinity). The statistical significance of the impact of polymorph type (akhtenskite ε-MnO₂, birnessite δ-MnO₂, cryptomelane α-MnO₂ and pyrolusite β-MnO₂), pH (2–9) and ionic strength (1–50 mmol/L) of solution on the adsorption level of Mn was investigated. The analysis of variance and the non-parametric Kruskal–Wallis H test were applied. Before and after Mn adsorption, the tested polymorphs were characterized using X-ray diffraction, scanning electron microscope techniques and gas porosimetry analysis. Here we demonstrated the significant differences in adsorption level between MnO₂ polymorphs’ type and pH; however, the statistical analysis proves that the type of MnO₂ has a four times stronger influence. There was no statistical significance for the ionic strength parameter. We showed that the high adsorption of Mn on the poorly crystalline polymorphs leads to the blockage of micropores in akhtenskite and, contrary, causes the development of the surface structure of birnessite. At the same time, no changes in the surfaces of cryptomelane and pyrolusite, the highly crystalline polymorphs, were found due to the very small loading by the adsorbate. Full article

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Open AccessReview

The Integration of Biopolymer-Based Materials for Energy Storage Applications: A Review

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Shrey Dalwadi

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Arnav Goel

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Constantine Kapetanakis

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David Salas-de la Cruz

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Xiao Hu

Int. J. Mol. Sci. 2023, 24(4), 3975; https://doi.org/10.3390/ijms24043975 - 16 Feb 2023

Cited by 1 | Viewed by 1623

Abstract

Biopolymers are an emerging class of novel materials with diverse applications and properties such as superior sustainability and tunability. Here, applications of biopolymers are described in the context of energy storage devices, namely lithium-based batteries, zinc-based batteries, and capacitors. Current demand for energy [...] Read more.

Biopolymers are an emerging class of novel materials with diverse applications and properties such as superior sustainability and tunability. Here, applications of biopolymers are described in the context of energy storage devices, namely lithium-based batteries, zinc-based batteries, and capacitors. Current demand for energy storage technologies calls for improved energy density, preserved performance overtime, and more sustainable end-of-life behavior. Lithium-based and zinc-based batteries often face anode corrosion from processes such as dendrite formation. Capacitors typically struggle with achieving functional energy density caused by an inability to efficiently charge and discharge. Both classes of energy storage need to be packaged with sustainable materials due to their potential leakages of toxic metals. In this review paper, recent progress in energy applications is described for biocompatible polymers such as silk, keratin, collagen, chitosan, cellulose, and agarose. Fabrication techniques are described for various components of the battery/capacitors including the electrode, electrolyte, and separators with biopolymers. Of these methods, incorporating the porosity found within various biopolymers is commonly used to maximize ion transport in the electrolyte and prevent dendrite formations in lithium-based, zinc-based batteries, and capacitors. Overall, integrating biopolymers in energy storage solutions poses a promising alternative that can theoretically match traditional energy sources while eliminating harmful consequences to the environment. Full article

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Open AccessArticle

Enzyme Conditioning of Chicken Collagen and Taguchi Design of Experiments Enhancing the Yield and Quality of Prepared Gelatins

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Pavel Mokrejš

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Robert Gál

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Jana Pavlačková

Int. J. Mol. Sci. 2023, 24(4), 3654; https://doi.org/10.3390/ijms24043654 - 11 Feb 2023

Viewed by 906

Abstract

During the production of mechanically deboned chicken meat (MDCM), a by-product is created that has no adequate use and is mostly disposed of in rendering plants. Due to the high content of collagen, it is a suitable raw material for the production of [...] Read more.

During the production of mechanically deboned chicken meat (MDCM), a by-product is created that has no adequate use and is mostly disposed of in rendering plants. Due to the high content of collagen, it is a suitable raw material for the production of gelatin and hydrolysates. The purpose of the paper was to process the MDCM by-product into gelatin by 3-step extraction. An innovative method was used to prepare the starting raw material for gelatin extraction, demineralization in HCl, and conditioning with a proteolytic enzyme. A Taguchi design with two process factors (extraction temperature and extraction time) was used at three levels (42, 46, and 50 °C; 20, 40, and 60 min) to optimize the processing of the MDCM by-product into gelatins. The gel-forming and surface properties of the prepared gelatins were analyzed in detail. Depending on the processing conditions, gelatins are prepared with a gel strength of up to 390 Bloom, a viscosity of 0.9–6.8 mPa·s, a melting point of 29.9–38.4 °C, a gelling point of 14.9–17.6 °C, excellent water- and fat-holding capacity, and good foaming and emulsifying capacity and stability. The advantage of MDCM by-product processing technology is a very high degree of conversion (up to 77%) of the starting collagen raw material to gelatins and the preparation of 3 qualitatively different gelatin fractions suitable for a wide range of food, pharmaceutical, and cosmetic applications. Gelatins prepared from MDCM by-product can expand the offer of gelatins from other than beef and pork tissues. Full article

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Open AccessArticle

Insight into the Molecule Impact of Critical-Sized UHMWPE-ALN Wear Particles on Cells by the Alginate-Encapsulated Cell Reactor

by

Yumei Liu

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Feng Shi

and

Shuxin Qu

Int. J. Mol. Sci. 2023, 24(4), 3510; https://doi.org/10.3390/ijms24043510 - 09 Feb 2023

Viewed by 779

Abstract

Wear particles of ultra-high molecular weight polyethylene (UHMWPE) are inevitable during service as joint prosthesis, and particles ≤ 10 μm with critical size could cause serious osteolysis and aseptic loosening of joint prosthesis. The aim of this study is to adopt the alginate-encapsulated [...] Read more.

Wear particles of ultra-high molecular weight polyethylene (UHMWPE) are inevitable during service as joint prosthesis, and particles ≤ 10 μm with critical size could cause serious osteolysis and aseptic loosening of joint prosthesis. The aim of this study is to adopt the alginate-encapsulated cell reactor to investigate the molecular impact of critical-sized wear particles of UHMWPE loaded with alendronate sodium (UHMWPE-ALN) on cells. Results showed that compared with UHMWPE wear particles, UHMWPE-ALN wear particles inhibited the proliferation of macrophages significantly after being co-cultured for 1, 4, 7, and 14 d. Furthermore, the released ALN promoted early apoptosis, suppressed the secretion of TNF-α and IL-6 of macrophages, and down-regulated relative gene expressions of TNF-α, IL-6, and IL-1β and RANK. In addition, compared with UHMWPE wear particles, UHMWPE-ALN wear particles promoted the ALP activity of osteoblasts, down-regulated the gene expression of RANKL, and up-regulated gene expression of osteoprotegerin. There were mainly two approaches of the effects of critical-sized UHMWPE-ALN wear particles on cells, one of which was cytology and the other was cytokine signal pathway. The former mainly affected the proliferation and activity of macrophages and osteoblasts. The latter would inhibit osteoclasts via cytokine and RANKL/RANK signal pathway. Thus, UHMWPE-ALN had the potential application in clinics to treat osteolysis induced by wear particles. Full article

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Open AccessArticle

Unusual Square Pyramidal Chalcogenide Mo₅ Cluster with Bridging Pyrazolate-Ligands

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Andrey Y. Komarovskikh

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Mikhail M. Syrokvashin

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Michael A. Shestopalov

Int. J. Mol. Sci. 2023, 24(4), 3440; https://doi.org/10.3390/ijms24043440 - 08 Feb 2023

Viewed by 990

Abstract

The family of chalcogenide molybdenum clusters is well presented in the literature by a series of compounds of nuclearity ranging from binuclear to multinuclear articulating octahedral fragments. Clusters actively studied in the last decades were shown to be promising as components of superconducting, [...] Read more.

The family of chalcogenide molybdenum clusters is well presented in the literature by a series of compounds of nuclearity ranging from binuclear to multinuclear articulating octahedral fragments. Clusters actively studied in the last decades were shown to be promising as components of superconducting, magnetic, and catalytic systems. Here, we report the synthesis and detailed characterization of new and unusual representatives of chalcogenide clusters: square pyramidal complexes [{Mo₅(μ₃-Se)ⁱ₄(μ₄-Se)ⁱ(μ-pz)ⁱ₄}(pzH)^t₅]^1+/2+ (pzH = pyrazole, i = inner, t = terminal). Individually obtained oxidized (2+) and reduced (1+) forms have very close geometry (proven by single-crystal X-ray diffraction analysis) and are able to reversibly transform into each other, which was confirmed by cyclic voltammetry. Comprehensive characterization of the complexes, both in solid and in solution, confirms the different charge state of molybdenum in clusters (XPS), magnetic properties (EPR), and so on. DFT calculations complement the diverse study of new complexes, expanding the chemistry of molybdenum chalcogenide clusters. Full article

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Open AccessArticle

Response Surface Methodology to Efficiently Optimize Intracellular Delivery by Photoporation

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Int. J. Mol. Sci. 2023, 24(4), 3147; https://doi.org/10.3390/ijms24043147 - 05 Feb 2023

Cited by 1 | Viewed by 1276

Abstract

Photoporation is an up-and-coming technology for the gentle and efficient transfection of cells. Inherent to the application of photoporation is the optimization of several process parameters, such as laser fluence and sensitizing particle concentration, which is typically done one factor at a time [...] Read more.

Photoporation is an up-and-coming technology for the gentle and efficient transfection of cells. Inherent to the application of photoporation is the optimization of several process parameters, such as laser fluence and sensitizing particle concentration, which is typically done one factor at a time (OFAT). However, this approach is tedious and runs the risk of missing a global optimum. Therefore, in this study, we explored whether response surface methodology (RSM) would allow for more efficient optimization of the photoporation procedure. As a case study, FITC-dextran molecules of 500 kDa were delivered to RAW264.7 mouse macrophage-like cells, making use of polydopamine nanoparticles (PDNPs) as photoporation sensitizers. Parameters that were varied to obtain an optimal delivery yield were PDNP size, PDNP concentration and laser fluence. Two established RSM designs were compared: the central composite design and the Box-Behnken design. Model fitting was followed by statistical assessment, validation, and response surface analysis. Both designs successfully identified a delivery yield optimum five- to eight-fold more efficiently than when using OFAT methodology while revealing a strong dependence on PDNP size within the design space. In conclusion, RSM proves to be a valuable approach to efficiently optimize photoporation conditions for a particular cell type. Full article

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Open AccessArticle

Mechanical Properties of Twisted Carbon Nanotube Bundles with Carbon Linkers from Molecular Dynamics Simulations

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Int. J. Mol. Sci. 2023, 24(3), 2473; https://doi.org/10.3390/ijms24032473 - 27 Jan 2023

Cited by 2 | Viewed by 841

Abstract

The manufacturing of high-modulus, high-strength fibers is of paramount importance for real-world, high-end applications. In this respect, carbon nanotubes represent the ideal candidates for realizing such fibers. However, their remarkable mechanical performance is difficult to bring up to the macroscale, due to the [...] Read more.

The manufacturing of high-modulus, high-strength fibers is of paramount importance for real-world, high-end applications. In this respect, carbon nanotubes represent the ideal candidates for realizing such fibers. However, their remarkable mechanical performance is difficult to bring up to the macroscale, due to the low load transfer within the fiber. A strategy to increase such load transfer is the introduction of chemical linkers connecting the units, which can be obtained, for example, using carbon ion-beam irradiation. In this work, we investigate, via molecular dynamics simulations, the mechanical properties of twisted nanotube bundles in which the linkers are composed of interstitial single carbon atoms. We find a significant interplay between the twist and the percentage of linkers. Finally, we evaluate the suitability of two different force fields for the description of these systems: the dihedral-angle-corrected registry-dependent potential, which we couple for non-bonded interaction with either the AIREBO potential or the screened potential ReboScr2. We show that both of these potentials show some shortcomings in the investigation of the mechanical properties of bundles with carbon linkers. Full article

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Open AccessArticle

An In-Situ Fabrication Method of ZnO and Other Zn(II) Compounds Containing Polypropylene Composites

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Karolina Halina Markiewicz

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Beata Kalska-Szostko

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Agnieszka Zofia Wilczewska

Int. J. Mol. Sci. 2023, 24(3), 2357; https://doi.org/10.3390/ijms24032357 - 25 Jan 2023

Viewed by 1190

Abstract

This study investigated the methods of preparation of zinc oxide-polypropylene nanocomposites and their antibacterial properties. Seven solutions with ZnO nanoparticles or zinc ions were formulated as a PP additive. Two methods of ZnO NPs syntheses were carried out: (1) a modified hydrothermal method [...] Read more.

This study investigated the methods of preparation of zinc oxide-polypropylene nanocomposites and their antibacterial properties. Seven solutions with ZnO nanoparticles or zinc ions were formulated as a PP additive. Two methods of ZnO NPs syntheses were carried out: (1) a modified hydrothermal method where a water solution of zinc acetate dihydrate, PEI, and ammonia were mixed with a final pH 11; (2) a thermal decomposition of a water solution of zinc acetate in the presence of PEI and ammonia using a two-screw extruder. During the experiments, the influence of various amounts of particle stabilizer, heating of the solutions, and the temperatures of the syntheses were examined. As a result, the simultaneous crystallization of ZnO in the extrusion process confirmed this method’s attractiveness from the application point of view. Fabricated PP-ZnO composite shows antibacterial properties against Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae. Full article

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Open AccessArticle

High Temperature CO₂ Capture Performance and Kinetic Analysis of Novel Potassium Stannate

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Int. J. Mol. Sci. 2023, 24(3), 2321; https://doi.org/10.3390/ijms24032321 - 24 Jan 2023

Viewed by 944

Abstract

For the first time, the use of stannate-based sorbents was investigated as high temperature CO₂ sorption to evaluate their potential to contribute towards reducing carbon emissions. The sorption capacity and kinetics of commercial tin oxide, sodium, potassium and calcium stannates and lab [...] Read more.

For the first time, the use of stannate-based sorbents was investigated as high temperature CO₂ sorption to evaluate their potential to contribute towards reducing carbon emissions. The sorption capacity and kinetics of commercial tin oxide, sodium, potassium and calcium stannates and lab synthesised potassium stannates were tested using thermogravimetric analysis. Commercial K₂SnO₃ was found to possess the largest CO₂ uptake capacity (2.77 mmol CO₂/g or 12.2 wt%) at 700 °C, which is among the highest for potassium sorbents, but the CO₂ desorption was not successful. On the contrary, the in-house synthesised K-stannate (K-B) using facile solid-state synthesis outperformed the other sorbents, resulting in a CO₂ uptake of 7.3 wt% after 5 min, an adsorption rate (0.016 mg/s) one order of magnitude higher than the other stannates, and stability after 40 cycles. The XRD and XPS analyses showed that K-B contains a mixture of K₂SnO₃ (76%) and K₄SnO₄ (21%), while the Scherrer crystal sizes confirmed good resistance to sintering for the potassium stannates. Among the apparent kinetic model tested, the pseudo-second order model was the most suitable to predict the CO₂ sorption process of K-B, indicating that chemical adsorption is dominant, while film-diffusion resistance and intra-particle diffusion resistance governed the sorption process in K-B. In summary, this work shows that solid-state synthesised potassium stannate could be an effective sorbent for high temperature separation, and additional work is required to further elucidate its potential. Full article

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Open AccessArticle

Insight into the Varying Reactivity of Different Catalysts for CO₂ Cycloaddition into Styrene Oxide: An Experimental and DFT Study

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Int. J. Mol. Sci. 2023, 24(3), 2123; https://doi.org/10.3390/ijms24032123 - 20 Jan 2023

Viewed by 926

Abstract

The cycloaddition of CO₂ into epoxides to form cyclic carbonates is a highly sought-after reaction for its potential to both reduce and use CO₂, which is a greenhouse gas. In this paper, we present experimental and theoretical studies and a [...] Read more.

The cycloaddition of CO₂ into epoxides to form cyclic carbonates is a highly sought-after reaction for its potential to both reduce and use CO₂, which is a greenhouse gas. In this paper, we present experimental and theoretical studies and a mechanistic approach for three catalytic systems. First, as Lewis base catalysts, imidazole and its derivatives, then as a Lewis acid catalyst, ZnI₂ alone, and after that, the combined system of ZnI₂ and imidazole. In the former, we aimed to discover the reasons for the varied reactivities of five Lewis base catalysts. Furthermore, we succeeded in reproducing the experimental results and trends using DFT. To add, we emphasized the importance of non-covalent interactions and their role in reactivity. In our case, the presence of a hydrogen bond was a key factor in decreasing the reactivity of some catalysts, thus leading to lower conversion rates. Finally, mechanistically understanding this 100% atom economy reaction can aid experimental chemists in designing better and more efficient catalytic systems. Full article

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Open AccessArticle

New Preparative Approach to Purer Technetium-99 Samples—Tetramethylammonium Pertechnetate: Deep Understanding and Application of Crystal Structure, Solubility, and Its Conversion to Technetium Zero Valent Matrix

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Anastasiia V. Sitanskaia

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Int. J. Mol. Sci. 2023, 24(3), 2015; https://doi.org/10.3390/ijms24032015 - 19 Jan 2023

Viewed by 1026

Abstract

⁹⁹Tc is one of the predominant fission products of ²³⁵U and an important component of nuclear industry wastes. The long half-life and specific activity of ⁹⁹Tc (212,000 y, 0.63 GBq g⁻¹) makes Tc a hazardous material. Two principal [...] Read more.

⁹⁹Tc is one of the predominant fission products of ²³⁵U and an important component of nuclear industry wastes. The long half-life and specific activity of ⁹⁹Tc (212,000 y, 0.63 GBq g⁻¹) makes Tc a hazardous material. Two principal ways were proposed for its disposal, namely, long-term storage and transmutation. Conversion to metal-like technetium matrices is highly desirable for both cases and for the second one the reasonably high Tc purity was important too. Tetramethylammonium pertechnetate (TMAP) was proposed here as a prospective precursor for matrix manufacture. It provided with very high decontamination factors from actinides (that is imperative for transmutation) by means of recrystallisation and it was based on the precise data on TMAP solubility and thermodynamics accomplished in the temperature range of 3–68 °C. The structure of solid pertechnetates were re-estimated with precise X-ray structure solution and compared to its Re and Cl analogues and tetrabutylammonium analogue as well. Differential thermal and evolved gas analysis in a flow of Ar–5% H₂ gas mixture showed that the major products of thermolysis were pure metallic technetium in solid matrix, trimethylammonium, carbon dioxide, and water in gas phase. High decontamination factors have been achieved when TMAP was used as an intermediate precursor for Tc. Full article

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Open AccessReview

Targeting Agents in Biomaterial-Mediated Bone Regeneration

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Miguel Gisbert-Garzarán

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María Natividad Gómez-Cerezo

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María Vallet-Regí

Int. J. Mol. Sci. 2023, 24(3), 2007; https://doi.org/10.3390/ijms24032007 - 19 Jan 2023

Viewed by 1040

Abstract

Bone diseases are a global public concern that affect millions of people. Even though current treatments present high efficacy, they also show several side effects. In this sense, the development of biocompatible nanoparticles and macroscopic scaffolds has been shown to improve bone regeneration [...] Read more.

Bone diseases are a global public concern that affect millions of people. Even though current treatments present high efficacy, they also show several side effects. In this sense, the development of biocompatible nanoparticles and macroscopic scaffolds has been shown to improve bone regeneration while diminishing side effects. In this review, we present a new trend in these materials, reporting several examples of materials that specifically recognize several agents of the bone microenvironment. Briefly, we provide a subtle introduction to the bone microenvironment. Then, the different targeting agents are exposed. Afterward, several examples of nanoparticles and scaffolds modified with these agents are shown. Finally, we provide some future perspectives and conclusions. Overall, this topic presents high potential to create promising translational strategies for the treatment of bone-related diseases. We expect this review to provide a comprehensive description of the incipient state-of-the-art of bone-targeting agents in bone regeneration. Full article

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Open AccessArticle

In Vivo Degradation Behavior of Magnesium Alloy for Bone Implants with Improving Biological Activity, Mechanical Properties, and Corrosion Resistance

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Int. J. Mol. Sci. 2023, 24(2), 1602; https://doi.org/10.3390/ijms24021602 - 13 Jan 2023

Viewed by 1180

Abstract

This study aimed to establish a surface modification technology for ZK60 magnesium alloy implants that can degrade uniformly over time and promote bone healing. It proposes a special micro-arc oxidation (MAO) treatment on ZK60 alloy that enables the composite electrolytes to create a [...] Read more.

This study aimed to establish a surface modification technology for ZK60 magnesium alloy implants that can degrade uniformly over time and promote bone healing. It proposes a special micro-arc oxidation (MAO) treatment on ZK60 alloy that enables the composite electrolytes to create a coating with better corrosion resistance and solve the problems of uneven and excessive degradation. A magnesium alloy bone screw made in this way was able to promote the bone healing reaction after implantation in rabbits. Additionally, it was found that the MAO-treated samples could be sustained in simulated body-fluid solution, exhibiting excellent corrosion resistance and electrochemical stability. The Ca ions deposited in the MAO coating were not cytotoxic and were beneficial in enhancing bone healing after implantation. Full article

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Open AccessArticle

Superfast Capture of Iodine from Air, Water, and Organic Solvent by Potential Dithiocarbamate-Based Organic Polymer

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Liya Thurakkal

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Subba Rao Cheekatla

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Mintu Porel

Int. J. Mol. Sci. 2023, 24(2), 1466; https://doi.org/10.3390/ijms24021466 - 11 Jan 2023

Cited by 1 | Viewed by 1321

Abstract

Organic polymers are widely explored due to their high stability, scalability, and more facile modification properties. We developed cost-effective dithiocarbamate-based organic polymers synthesized using diamides, carbon disulfide, and diamines to apply for environmental remediation. The sequestration of radioiodine is a serious concern to [...] Read more.

Organic polymers are widely explored due to their high stability, scalability, and more facile modification properties. We developed cost-effective dithiocarbamate-based organic polymers synthesized using diamides, carbon disulfide, and diamines to apply for environmental remediation. The sequestration of radioiodine is a serious concern to tackle when dealing with nuclear power for energy requirements. However, many of the current sorbents have the problem of slower adsorption for removing iodine. In this report, we discuss the utilization of an electron-rich dithiocarbamate-based organic polymer for the removal of iodine in a very short time and with high uptake. Our material showed 2.8 g/g uptake of vapor iodine in 1 h, 915.19 mg/g uptake of iodine from cyclohexane within 5 s, 93% removal of saturated iodine from water in 1 min, and 1250 mg/g uptake of triiodide ions from water within 30 s. To the best of our knowledge, the iodine capture was faster than previously observed for any existing material. The material was fully recyclable when applied for up to four cycles. Hence, this dithiocarbamate-based polymer can be a promising system for the fast removal of various forms of iodine and, thus, enhance environmental security. Full article

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Open AccessArticle

Synthesis, Photochemistry, Computational Study and Potential Application of New Styryl-Thiophene and Naphtho-Thiophene Benzylamines

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Int. J. Mol. Sci. 2023, 24(1), 610; https://doi.org/10.3390/ijms24010610 - 29 Dec 2022

Cited by 1 | Viewed by 890

Abstract

In this research, the synthesis, photochemistry, and computational study of new cis- and trans-isomers of amino-thienostilbenes is performed to test the efficiency of their production and acid resistance, and to investigate their electronic structure, photoreactivity, photophysical characteristics, and potential biological activity. [...] Read more.

In this research, the synthesis, photochemistry, and computational study of new cis- and trans-isomers of amino-thienostilbenes is performed to test the efficiency of their production and acid resistance, and to investigate their electronic structure, photoreactivity, photophysical characteristics, and potential biological activity. The electronic structure and conformations of synthesized thienostilbene amines and their photocyclization products are examined computationally, along with molecular modeling of amines possessing two thiophene rings that showed inhibitory potential toward cholinesterases. New amino-styryl thiophenes, with favorable photophysical properties and proven acid resistance, represent model compounds for their water-soluble ammonium salts as potential styryl optical dyes. The comparison with organic dyes possessing a trans-aminostilbene subunit as the scaffold shows that the newly synthesized trans-aminostilbenes have very similar absorbance wavelengths. Furthermore, their functionalized cis-isomers and photocyclization products are good candidates for cholinesterase inhibitors because of the structural similarity of the molecular skeleton to some already proven bioactive derivatives. Full article

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Open AccessArticle

PEO Coatings Modified with Halloysite Nanotubes: Composition, Properties, and Release Performance

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Int. J. Mol. Sci. 2023, 24(1), 305; https://doi.org/10.3390/ijms24010305 - 24 Dec 2022

Cited by 2 | Viewed by 799

Abstract

In this work, the properties of the coatings formed on the Mg-Mn-Ce alloy by plasma electrolytic oxidation (PEO) in electrolytes containing halloysite nanotubes (HNTs) were investigated. The incorporation of halloysite nanotubes into the PEO coatings improved their mechanical characteristics, increased thickness, and corrosion [...] Read more.

In this work, the properties of the coatings formed on the Mg-Mn-Ce alloy by plasma electrolytic oxidation (PEO) in electrolytes containing halloysite nanotubes (HNTs) were investigated. The incorporation of halloysite nanotubes into the PEO coatings improved their mechanical characteristics, increased thickness, and corrosion resistance. The studied layers reduced corrosion current density by more than two times in comparison with the base PEO layer without HNTs (from 1.1 × 10⁻⁷ A/cm² to 4.9 × 10⁻⁸ A/cm²). The presence of halloysite nanotubes and products of their dihydroxylation that were formed under the PEO conditions had a positive impact on the microhardness of the obtained layers (this parameter increased from 4.5 ± 0.4 GPa to 7.3 ± 0.5 GPa). In comparison with the base PEO layer, coatings containing halloysite nanotubes exhibited sustained release and higher adsorption capacity regarding caffeine. Full article

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Open AccessArticle

Removal of Pb²⁺, CrT, and Hg²⁺ Ions from Aqueous Solutions Using Amino-Functionalized Magnetic Nanoparticles

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A. F. P. Allwin Mabes Raj

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Int. J. Mol. Sci. 2022, 23(24), 16186; https://doi.org/10.3390/ijms232416186 - 19 Dec 2022

Viewed by 921

Abstract

In this paper, a circular economy approach with the adsorption and desorption of heavy metal (HM) ions—i.e., lead (Pb²⁺), chromium (CrT), and mercury (Hg²⁺)—from aqueous solutions was studied. Specific and selective binding of HM ions was performed on stabilized [...] Read more.

In this paper, a circular economy approach with the adsorption and desorption of heavy metal (HM) ions—i.e., lead (Pb²⁺), chromium (CrT), and mercury (Hg²⁺)—from aqueous solutions was studied. Specific and selective binding of HM ions was performed on stabilized and amino-functionalized iron oxide magnetic nanoparticles (γ-Fe₂O₃@NH₂ NPs) from an aqueous solution at pH 4 and 7. For this purpose, γ-Fe₂O₃@NH₂ NPs were characterized by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), specific surface area (BET), transmission electron microscopy (TEM), EDXS, and zeta potential measurements (ζ). The effects of different adsorbent amounts (m_ads = 20/45/90 mg) and the type of anions (NO₃⁻, Cl⁻, SO₄²⁻) on adsorption efficiency were also tested. The desorption was performed with 0.1 M HNO₃. The results showed improvement of adsorption efficiency for CrT, Pb²⁺, and Hg²⁺ ions at pH 7 by 45 mg of g-Fe₂O₃@NH₂ NPs, and the sequence was as follows: CrT > Hg²⁺ > Pb²⁺, with adsorption capacities of 90.4 mg/g, 85.6 mg/g, and 83.6 mg/g, respectively. The desorption results showed the possibility for the reuse of γ-Fe₂O₃@NH₂ NPs with HNO₃, as the desorption efficiency was 100% for Hg²⁺ ions, 96.7% for CrT, and 91.3% for Pb²⁺. Full article

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Open AccessArticle

New Gd³⁺ and Mn²⁺-Co-Doped Scheelite-Type Ceramics—Their Structural, Optical and Magnetic Properties

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Hubert Fuks

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Paweł Kochmański

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Elżbieta Tomaszewicz

Int. J. Mol. Sci. 2022, 23(24), 15740; https://doi.org/10.3390/ijms232415740 - 12 Dec 2022

Cited by 1 | Viewed by 659

Abstract

New Gd³⁺- and Mn²⁺-co-doped calcium molybdato-tungstates with the chemical formula of Ca_1−3x−yMn_y▯_xGd_2x(MoO₄)_1−3x(WO₄)_3x (labeled later as CaMnGdMoWO), where ▯ [...] Read more.

New Gd³⁺- and Mn²⁺-co-doped calcium molybdato-tungstates with the chemical formula of Ca_1−3x−yMn_y▯_xGd_2x(MoO₄)_1−3x(WO₄)_3x (labeled later as CaMnGdMoWO), where ▯ denotes vacant sites in the crystal lattice, 0 < x ≤ 0.2500 and y = 0.0200 as well as 0 < y ≤ 0.0667 and x = 0.1667 were successfully synthesized by high-temperature solid-state reaction method and combustion route. Obtained ceramic materials crystallize in scheelite-type structure with space group I4₁/a. Morphological features and grain sizes of powders under study were investigated by SEM technique. Spectroscopic studies within the UV-vis spectral range were carried out to estimate the direct band gap (E_g) and Urbach energy (E_U) of obtained powders. EPR studies confirmed the existence of two types of magnetic objects, i.e., Mn²⁺ and Gd³⁺ ions, and significant antiferromagnetic (AFM) interactions among them. Full article

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Open AccessArticle

A Predictive Pharmacokinetic Model for Immune Cell-Mediated Uptake and Retention of Nanoparticles in Tumors

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Int. J. Mol. Sci. 2022, 23(24), 15664; https://doi.org/10.3390/ijms232415664 - 10 Dec 2022

Cited by 1 | Viewed by 892

Abstract

A promise of cancer nanomedicine is the “targeted” delivery of therapeutic agents to tumors by the rational design of nanostructured materials. During the past several decades, a realization that in vitro and in vivo preclinical data are unreliable predictors of successful clinical translation [...] Read more.

A promise of cancer nanomedicine is the “targeted” delivery of therapeutic agents to tumors by the rational design of nanostructured materials. During the past several decades, a realization that in vitro and in vivo preclinical data are unreliable predictors of successful clinical translation has motivated a reexamination of this approach. Mathematical models of drug pharmacokinetics (PK) and biodistribution (BD) are essential tools for small-molecule drugs development. A key assumption underlying these models is that drug-target binding kinetics dominate blood clearance, hence recognition by host innate immune cells is not explicitly included. Nanoparticles circulating in the blood are conspicuous to phagocytes, and inevitable interactions typically trigger active biological responses to sequester and remove them from circulation. Our recent findings suggest that, instead of referring to nanoparticles as designed for active or passive “tumor targeting”, we ought rather to refer to immune cells residing in the tumor microenvironment (TME) as active or passive actors in an essentially “cell-mediated tumor retention” process that competes with active removal by other phagocytes. Indeed, following intravenous injection, nanoparticles induce changes in the immune compartment of the TME because of nanoparticle uptake, irrespective of the nature of tumor targeting moieties. In this study, we propose a 6-compartment PK model as an initial mathematical framework for modeling this tumor-associated immune cell-mediated retention. Published in vivo PK and BD results obtained with bionized nanoferrite^® (BNF^®) nanoparticles were combined with results from in vitro internalization experiments with murine macrophages to guide simulations. As a preliminary approximation, we assumed that tumor-associated macrophages (TAMs) are solely responsible for active retention in the TME. We model the TAM approximation by relating in vitro macrophage uptake to an effective macrophage avidity term for the BNF^® nanoparticles under consideration. Full article

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Open AccessArticle

Synthesis of Hybrid Epoxy Methacrylate Resin Based on Diglycidyl Ethers and Coatings Preparation via Cationic and Free-Radical Photopolymerization

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Paula Ossowicz-Rupniewska

Int. J. Mol. Sci. 2022, 23(24), 15592; https://doi.org/10.3390/ijms232415592 - 09 Dec 2022

Viewed by 717

Abstract

A series of difunctional epoxy methacrylate resins (EAs) containing at least one epoxy and at least one methacrylate group were synthesized by means of an addition reaction between epoxy-terminated diglycidyl ethers and methacrylic acid. In order to investigate the impact of polymer architecture [...] Read more.

A series of difunctional epoxy methacrylate resins (EAs) containing at least one epoxy and at least one methacrylate group were synthesized by means of an addition reaction between epoxy-terminated diglycidyl ethers and methacrylic acid. In order to investigate the impact of polymer architecture on the course of addition reactions and further coating properties, several different types of diglycidyl ethers, i.e., linear, containing aliphatic or aromatic rings, with a short or polymeric backbone, were employed in the synthesis. The carboxyl–epoxide addition esterification reactions have been found to, in a relatively straightforward manner, control the extent of acrylation depending on the substrate feed ratio and reaction time. The structure of obtained pre-polymers was evaluated by FT-IR and NMR methods. At the same time, the extent of addition reactions was validated via quantitative analysis, including non-volatile matter content (NV), acid value (PAVs), and epoxy equivalent value (EE) analysis. The modification was carried out in a manner likely to create a compound with one epoxy and one carbon–carbon pendant group. Hence, due to the presence of both functionalities, it is possible to crosslink compositions based on synthesized EAs via two distinct mechanisms: (i) cationic polymerization or (ii) free-radical polymerization. Synthesized epoxy methacrylate pre-polymers were further employed for use in formulate photocurable coating compositions by the cationic or radical process. Furthermore, the photopolymerization behavior and properties of cured coatings were explored regarding some structural factors and parameters. The investigated polymeric materials cure in a short time to obtain coatings with good properties, which is why they can be successfully used to produce protective and decorative coatings for many industries. Full article

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Open AccessArticle

Competing Routes in the Extraction of Lanthanide Nitrates by 1,10-Phenanthroline-2,9-diamides: An Impact of Structure of Complexes on the Extraction

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Valentine G. Nenajdenko

Int. J. Mol. Sci. 2022, 23(24), 15538; https://doi.org/10.3390/ijms232415538 - 08 Dec 2022

Cited by 1 | Viewed by 862

Abstract

The fact of the fracture of the extraction curve of lanthanides by 1,10-phenanthroline-2,9-diamides is explained in terms of the structure of complexes, solvent extraction data and quantum chemical calculations. The solvent extraction proceeds in two competing directions: in the form of neutral complexes [...] Read more.

The fact of the fracture of the extraction curve of lanthanides by 1,10-phenanthroline-2,9-diamides is explained in terms of the structure of complexes, solvent extraction data and quantum chemical calculations. The solvent extraction proceeds in two competing directions: in the form of neutral complexes LLn(NO₃)₃ and in the form of tight ion pairs {[LLn(NO₃)₂ H₂O]⁺ (NO₃⁻). Full article

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Open AccessArticle

Nanocomposites of Nitrogen-Doped Graphene Oxide and Manganese Oxide for Photodynamic Therapy and Magnetic Resonance Imaging

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Int. J. Mol. Sci. 2022, 23(23), 15087; https://doi.org/10.3390/ijms232315087 - 01 Dec 2022

Cited by 3 | Viewed by 955

Abstract

Cancer is a leading cause of death worldwide. Conventional methods of cancer treatment, including chemotherapy and radiotherapy, are associated with multiple side effects. Recently, photodynamic therapy (PDT) has emerged as an effective therapeutic modality for cancer treatment without adversely affecting normal tissue. In [...] Read more.

Cancer is a leading cause of death worldwide. Conventional methods of cancer treatment, including chemotherapy and radiotherapy, are associated with multiple side effects. Recently, photodynamic therapy (PDT) has emerged as an effective therapeutic modality for cancer treatment without adversely affecting normal tissue. In this study, we synthesized nitrogen doped graphene (NDG) and conjugated it with Mn₃O₄ nanoparticles to produce NDG-Mn₃O₄ nanocomposite with the aim of testing its bimodal performance including PDT and magnetic resonance imaging (MRI). We did not use any linker or binder for conjugation between NDG and Mn₃O₄, rather they were anchored by a milling process. The results of cell viability analysis showed that NDG-Mn₃O₄ nanocomposites caused significant cell death under laser irradiation, while control and Mn₃O₄ nanoparticles showed negligible cell death. We observed increased generation of singlet oxygen after exposure of NDG-Mn₃O₄ nanocomposites, which was directly proportional to the duration of laser irradiation. The results of MRI showed concentration dependent enhancement of signal intensity with an increasing concentration of NDG-Mn₃O₄ nanocomposites. In conclusion, NDG-Mn₃O₄ nanocomposites did not cause any cytotoxicity under physiological conditions. However, they produced significant and dose-dependent cytotoxicity in cancer cells after laser irradiation. NDG-Mn₃O₄ nanocomposites also exhibited concentration-dependent MRI contrast property, suggesting their possible application for cancer imaging. Further studies are warranted to test the theranostic potential of NDG-Mn₃O₄ nanocomposites using animal models of cancer. Full article

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Open AccessArticle

Enhanced Acetaminophen Electrochemical Sensing Based on Nitrogen-Doped Graphene

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Lidia Magerusan

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Florina Pogacean

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Stela Pruneanu

Int. J. Mol. Sci. 2022, 23(23), 14866; https://doi.org/10.3390/ijms232314866 - 28 Nov 2022

Cited by 2 | Viewed by 894

Abstract

Because of the widespread acetaminophen usage and the danger of harmful overdosing effects, developing appropriate procedures for its quantitative and qualitative assay has always been an intriguing and fascinating problem. A quick, inexpensive, and environmentally friendly approach based on direct voltage anodic graphite [...] Read more.

Because of the widespread acetaminophen usage and the danger of harmful overdosing effects, developing appropriate procedures for its quantitative and qualitative assay has always been an intriguing and fascinating problem. A quick, inexpensive, and environmentally friendly approach based on direct voltage anodic graphite rod exfoliation in the presence of inorganic salt aqueous solution ((NH₄)₂SO₄–0.3 M) has been established for the preparation of nitrogen-doped graphene (exf-NGr). The XRD analysis shows that the working material appears as a mixture of few (76.43%) and multi-layers (23.57%) of N-doped graphenes. From XPS, the C/O ratio was calculated to be 0.39, indicating a significant number of structural defects and the existence of multiple oxygen-containing groups at the surface of graphene sheets caused by heteroatom doping. Furthermore, the electrochemical performances of glassy carbon electrodes (GCEs) modified with exf-NGr for acetaminophen (AMP) detection and quantification have been assessed. The exf-NGr/GCE-modified electrode shows excellent reproducibility, stability, and anti-interfering characteristics with improved electrocatalytic activity over a wide detection range (0.1–100 µM), with a low limit for AMP detection (LOD = 3.03 nM). In addition, the developed sensor has been successfully applied in real sample analysis for the AMP quantification from different commercially available pharmaceutical formulations. Full article

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Open AccessArticle

Effect of Cross-Linking Cations on In Vitro Biocompatibility of Apple Pectin Gel Beads

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Sergey Popov

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Nikita Paderin

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Elizaveta Chistiakova

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Dmitry Ptashkin

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Pavel A. Markov

Int. J. Mol. Sci. 2022, 23(23), 14789; https://doi.org/10.3390/ijms232314789 - 26 Nov 2022

Cited by 3 | Viewed by 806

Abstract

The study aimed to compare the in vitro biocompatibility of pectin gels formed by different cross-linking cations. Hydrogel beads named CaPG, ZnPG, FePG, and AlPG were prepared from 4% solutions of apple pectin using ionotropic gelling with CaCl₂, ZnCl₂, [...] Read more.

The study aimed to compare the in vitro biocompatibility of pectin gels formed by different cross-linking cations. Hydrogel beads named CaPG, ZnPG, FePG, and AlPG were prepared from 4% solutions of apple pectin using ionotropic gelling with CaCl₂, ZnCl₂, FeCl₃, and AlCl₃, respectively. Cations influenced the gel strength of the wet gel beads in the following order (least strong) Ca²⁺ < Zn²⁺ < Fe³⁺~Al³⁺ (most strong). The swelling degree of the CaPG beads after 24 h of incubation in the RPMI-1640 medium was 104%, whereas the ZnPG, FePG, and AlPG beads swelled by 76, 108, and 134%, respectively. The strength of the pectin gel decreased significantly after incubation in the RPMI-1640 medium for 24 h, regardless of the cross-linking cation, although the FePG beads remained the strongest. All the pectin beads adsorbed serum proteins to a low degree, however the serum protein adsorption by the ZnPG and FePG beads (1.46 ± 0.87 and 1.35 ± 0.19 µg/mm²) was more than the CaPG and AlPG beads (0.31 ± 0.36 and 0.44 ± 0.25 µg/mm²). All the pectin beads reduced the production of TNF-α and IL-10 by hPBMCs in response to LPS stimulation. The IL-1β response of cells to LPS was significantly reduced by the CaPG, ZnPG, and FePG beads, whereas the AlPG beads enhanced it twofold. The CaPG, FePG, and AlPG beads had no cytotoxicity. The viability of hPBMCs and human fibroblasts incubated with ZnPG beads was 5.3 and 7.2%, respectively. Thus, the use of different cross-linking cations changed the properties of the pectin gel, which is important for biocompatibility. Full article

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Open AccessArticle

Solid Solutions of Lindbergite–Glushinskite Series: Synthesis, Ionic Substitutions, Phase Transformation and Crystal Morphology

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Anatolii V. Korneev

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Alina R. Izatulina

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Mariya A. Kuz’mina

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Olga V. Frank-Kamenetskaya

Int. J. Mol. Sci. 2022, 23(23), 14734; https://doi.org/10.3390/ijms232314734 - 25 Nov 2022

Viewed by 710

Abstract

To clarify the crystal chemical features of natural and synthetic oxalates Me²⁺(C₂O₄)∙2H₂O (Me²⁺ = Fe, Mn, Mg, Zn), including minerals of the humboldtine group, solid solutions of lindbergite Mn(C₂O₄)∙2H [...] Read more.

To clarify the crystal chemical features of natural and synthetic oxalates Me²⁺(C₂O₄)∙2H₂O (Me²⁺ = Fe, Mn, Mg, Zn), including minerals of the humboldtine group, solid solutions of lindbergite Mn(C₂O₄)∙2H₂O–glushinskite Mg(C₂O₄)∙2H₂O were precipitated under various conditions, close to those characteristic of mineralization in biofilms: at the stoichiometric ratios ((Mn + Mg)/C₂O₄ = 1) and non-stochiometric ratios ((Mn + Mg)/C₂O₄ < 1), in the presence and absence of citrate ions. Investigation of precipitates was carried out by powder X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Thermodynamic modelling was performed in order to evaluate the lindbergite–glushinskite equilibrium. It was shown that glushinskite belongs to the orthorhombic β-modification (sp. Gr. Fddd), while lindbergite has a monoclinic α-modification (sp. gr. C2/c). Mg ions incorporate lindbergite in much higher quantities than Mn ions incorporate glushinskite; moreover, Mn glushinskites are characterized by violations of long-range order in their crystal structure. Lindbergite–glushinskite transition occurs abruptly and can be classified as a first-order isodimorphic transition. The Me²⁺/C₂O₄ ratio and the presence of citric acid in the solution affect the isomorphic capacity of lindbergite and glushinskite, the width of the transition and the equilibrium Mg/Mn ratio. The transition is accompanied by continuous morphological changes in crystals and crystal intergrowths. Given the obtained results, it is necessary to take into account in biotechnologies aimed at the bioremediation/bioleaching of metals from media containing mixtures of cations (Mg, Mn, Fe, Zn). Full article

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Open AccessArticle

A Challenge toward Novel Quaternary Sulfides SrLnCuS₃ (Ln = La, Nd, Tm): Unraveling Synthetic Pathways, Structures and Properties

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Anna V. Ruseikina

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Maxim V. Grigoriev

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Leonid A. Solovyov

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Vladimir A. Chernyshev

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Aleksandr S. Aleksandrovsky

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Alexander A. Garmonov

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Int. J. Mol. Sci. 2022, 23(20), 12438; https://doi.org/10.3390/ijms232012438 - 18 Oct 2022

Cited by 2 | Viewed by 1527

Abstract

We report on the novel heterometallic quaternary sulfides SrLnCuS₃ (Ln = La, Nd, Tm), obtained as both single crystals and powdered samples. The structures of both the single crystal and powdered samples of SrLaCuS₃ and SrNdCuS₃ belong to the orthorhombic [...] Read more.

We report on the novel heterometallic quaternary sulfides SrLnCuS₃ (Ln = La, Nd, Tm), obtained as both single crystals and powdered samples. The structures of both the single crystal and powdered samples of SrLaCuS₃ and SrNdCuS₃ belong to the orthorhombic space group Pnma but are of different structural types, while both samples of SrTmCuS₃ crystallize in the orthorhombic space group Cmcm with the structural type KZrCuS₃. Three-dimensional crystal structures of SrLaCuS₃ and SrNdCuS₃ are formed from the (Sr/Ln)S₇ capped trigonal prisms and CuS₄ tetrahedra. In SrLaCuS₃, alternating 2D layers are stacked, while the main backbone of the structure of SrNdCuS₃ is a polymeric 3D framework [(Sr/Ln)S₇]_n, strengthened by 1D polymeric chains (CuS₄)_n with 1D channels, filled by the other Sr²⁺/Ln³⁺ cations, which, in turn, form 1D dimeric ribbons. A 3D crystal structure of SrTmCuS₃ is constructed from the SrS₆ trigonal prisms, TmS₆ octahedra and CuS₄ tetrahedra. The latter two polyhedra are packed together into 2D layers, which are separated by 1D chains (SrS₆)_n and 1D free channels. In both crystal structures of SrLaCuS₃ obtained in this work, the crystallographic positions of strontium and lanthanum were partially mixed, while only in the structure of SrNdCuS₃, solved from the powder X-ray diffraction data, were the crystallographic positions of strontium and neodymium partially mixed. Band gaps of SrLnCuS₃ (Ln = La, Nd, Tm) were found to be 1.86, 1.94 and 2.57 eV, respectively. Both SrNdCuS₃ and SrTmCuS₃ were found to be paramagnetic at 20–300 K, with the experimental magnetic characteristics being in good agreement with the corresponding calculated parameters. Full article

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Open AccessArticle

Experimental Study of the Impact of Trace Amounts of Acetylene and Methylacetylene on the Synthesis, Mechanical and Thermal Properties of Polypropylene

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Joaquín Hernández-Fernández

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Ricardo Vivas-Reyes

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Carlos A. T. Toloza

Int. J. Mol. Sci. 2022, 23(20), 12148; https://doi.org/10.3390/ijms232012148 - 12 Oct 2022

Cited by 7 | Viewed by 834

Abstract

During the production of polymer-grade propylene, different processes are used to purify this compound and ensure that it is of the highest quality. However, some impurities such as acetylene and methyl acetylene are difficult to remove, and some of these impurities may be [...] Read more.

During the production of polymer-grade propylene, different processes are used to purify this compound and ensure that it is of the highest quality. However, some impurities such as acetylene and methyl acetylene are difficult to remove, and some of these impurities may be present in the propylene used to obtain polypropylene, which may have repercussions on the process. This study evaluates the impact of these acetylene and methyl acetylene impurities on the productivity of the polypropylene synthesis process and on the mechanical and thermal properties of the material obtained through the synthesis of eight samples with different concentrations of acetylene and eight samples with different concentrations of acetylene. We discovered that for the first concentrations of both acetylene (2 and 3 ppm) and methyl acetylene (0.03 and 0.1), the MFI, thermal recording, and mechanical properties of the resin were unaffected by the variation of the fluidity index, thermal degradation by TGA, and mechanical properties such as resistance to tension, bending, and impact. However, when the concentration exceeded 14 ppm for methyl acetylene and 12 ppm for acetylene, the resistance of this resin began to decrease linearly. Regarding production, this was affected by the first traces of acetylene and methyl acetylene progressively decreasing. Full article

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Open AccessReview

Sodium Alginate—Natural Microencapsulation Material of Polymeric Microparticles

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Olimpia Daniela Frent

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Laura Gratiela Vicas

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Narcis Duteanu

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Claudia Mona Morgovan

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Tunde Jurca

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Annamaria Pallag

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Mariana Eugenia Muresan

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Sanda Monica Filip

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Roxana-Liana Lucaciu

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Eleonora Marian

Int. J. Mol. Sci. 2022, 23(20), 12108; https://doi.org/10.3390/ijms232012108 - 11 Oct 2022

Cited by 5 | Viewed by 2011

Abstract

From the multitude of materials currently available on the market that can be used in the development of microparticles, sodium alginate has become one of the most studied natural anionic polymers that can be included in controlled-release pharmaceutical systems alongside other polymers due [...] Read more.

From the multitude of materials currently available on the market that can be used in the development of microparticles, sodium alginate has become one of the most studied natural anionic polymers that can be included in controlled-release pharmaceutical systems alongside other polymers due to its low cost, low toxicity, biocompatibility, biodegradability and gelatinous die-forming capacity in the presence of Ca²⁺ ions. In this review, we have shown that through coacervation, the particulate systems for the dispensing of drugs consisting of natural polymers are nontoxic, allowing the repeated administration of medicinal substances and the protection of better the medicinal substances from degradation, which can increase the capture capacity of the drug and extend its release from the pharmaceutical form. Full article

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Open AccessArticle

Iron Oxide Powder as Responsible for the Generation of Industrial Polypropylene Waste and as a Co-Catalyst for the Pyrolysis of Non-Additive Resins

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Joaquín Hernández-Fernández

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John R. Castro-Suarez

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Carlos A. T. Toloza

Int. J. Mol. Sci. 2022, 23(19), 11708; https://doi.org/10.3390/ijms231911708 - 03 Oct 2022

Cited by 7 | Viewed by 1081

Abstract

For the synthesis of polymeric resins, it is of great importance to review the raw materials and the equipment to be used to avoid the presence of compounds that may affect the effectiveness of the polymerization and the characteristics of the plastic to [...] Read more.

For the synthesis of polymeric resins, it is of great importance to review the raw materials and the equipment to be used to avoid the presence of compounds that may affect the effectiveness of the polymerization and the characteristics of the plastic to be obtained. Iron oxide is a compound that can be present in reactors after maintenance due to the techniques used and the cleaning of this equipment, and it can affect the characteristics of the resins, reducing their quality. In this study, the presence of FeO in different concentrations was evaluated to determine its effects on the properties and pyrolysis of polypropylene resins by using X-ray refraction to determine the elements of the samples, evaluating thermal degradation by TGA, the variation in molecular weight by measuring the MFI, and the compounds obtained from pyrolysis by chromatography. The results showed that the thermal degradation decreased as the FeO concentration increased, while for the MFI, the relationship was directly proportional. The evaluation of the compounds obtained from pyrolysis showed an increase in the production of alcohols, alkynes, ketones, and acids, and a decrease in alkanes and alkenes, showing that FeO affects the properties of polypropylene and the compounds that are produced during pyrolysis. Full article

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Open AccessArticle

Synthesis of M-Ag₃PO₄, (M = Se, Ag, Ta) Nanoparticles and Their Antibacterial and Cytotoxicity Study

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Veeranoot Nissapatorn

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Maria de Lourdes Pereira

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Polrat Wilairatana

Int. J. Mol. Sci. 2022, 23(19), 11403; https://doi.org/10.3390/ijms231911403 - 27 Sep 2022

Cited by 2 | Viewed by 1653

Abstract

Silver Phosphate, Ag₃PO₄, being a highly capable clinical molecule, an ultrasonic method was employed to synthesize the M-Ag₃PO_4, (M = Se, Ag, Ta) nanoparticles which were evaluated for antibacterial and cytotoxicity activities post-characterization. Escherichia coli and [...] Read more.

Silver Phosphate, Ag₃PO₄, being a highly capable clinical molecule, an ultrasonic method was employed to synthesize the M-Ag₃PO_4, (M = Se, Ag, Ta) nanoparticles which were evaluated for antibacterial and cytotoxicity activities post-characterization. Escherichia coli and Staphylococcus aureus were used for antibacterial testing and the effects of sonication on bacterial growth with sub-MIC values of M-Ag₃PO₄ nanoparticles were examined. The effect of M-Ag₃PO₄ nanoparticles on human colorectal carcinoma cells (HCT-116) and human cervical carcinoma cells (HeLa cells) was examined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay and DAPI (4′,6-diamidino-2-phenylindole) staining. Additionally, we analyzed the effect of nanoparticles on normal and non-cancerous human embryonic kidney cells (HEK-293). Ag-Ag₃PO₄ exhibited enhanced antibacterial activity followed by Ta-Ag₃PO_4, Ag₃PO₄, and Se-Ag₃PO₄ nanoparticles against E. coli. Whereas the order of antibacterial activity against Staphylococcus aureus was Ag₃PO₄ > Ag-Ag₃PO₄ > Ta-Ag₃PO₄ > Se-Ag₃PO₄, respectively. Percentage inhibition of E. coli was 98.27, 74.38, 100, and 94.2%, while percentage inhibition of S. aureus was 25.53, 80.28, 99.36, and 20.22% after treatment with Ag₃PO₄, Se-Ag₃PO₄, Ag-Ag₃PO₄, and Ta-Ag₃PO_4, respectively. The MTT assay shows a significant decline in the cell viability after treating with M-Ag₃PO₄ nanoparticles. The IC₅₀ values for Ag₃PO_4, Se-Ag₃PO_4, Ag-Ag₃PO₄, and Ta-Ag₃PO₄ on HCT-116 were 39.44, 28.33, 60.24, 58.34 µg/mL; whereas for HeLa cells, they were 65.25, 61.27, 75.52, 72.82 µg/mL, respectively. M-Ag₃PO₄ nanoparticles did not inhibit HEK-293 cells. Apoptotic assay revealed that the numbers of DAPI stained cells were significantly lower in the M-Ag₃PO₄-treated cells versus control. Full article

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