Editorial

4 pages, 227 KiB

Open AccessEditorial

Biopolymer Composites 2022

by Ana M. Díez-Pascual

Int. J. Mol. Sci. 2023, 24(7), 6430; https://doi.org/10.3390/ijms24076430 - 29 Mar 2023

Viewed by 1091

Recently, sustainable, biodegradable, and nontoxic materials, especially from renewable resources, have gained a lot of attention, and an important effort has been put into the research of biodegradable and biocompatible polymers as an alternative to petroleum-based commodity plastics [...] Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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18 pages, 3768 KiB

Open AccessArticle

Fabrication and Characterization of Functional Biobased Membranes from Postconsumer Cotton Fabrics and Palm Waste for the Removal of Dyes

by Mohd Jahir Khan, Zoheb Karim, Boonya Charnnok, Thiprada Poonsawat, Pattaraporn Posoknistakul, Navadol Laosiripojana, Kevin C.-W. Wu and Chularat Sakdaronnarong

Int. J. Mol. Sci. 2023, 24(7), 6030; https://doi.org/10.3390/ijms24076030 - 23 Mar 2023

Cited by 4 | Viewed by 1278

Abstract

Textile industries currently face vast challenges for the active removal of colored wastewater. Indeed, sustainable, recyclable, and green approaches are still lacking to achieve this aim. Thus, the present study explored the utilization of highly functional, green, recyclable, fully bio-based, and cost-effective composite [...] Read more.

Textile industries currently face vast challenges for the active removal of colored wastewater. Indeed, sustainable, recyclable, and green approaches are still lacking to achieve this aim. Thus, the present study explored the utilization of highly functional, green, recyclable, fully bio-based, and cost-effective composite membranes from post-consumer cotton fabrics and palm waste for wastewater treatment purposes. Highly functional cellulose nanofibers (CNF) were produced from waste cotton fabrics and filter paper using an acid hydrolysis technique. The yield of nanofibers extracted from waste cotton fabrics and filter paper was 76.74 and 54.50%, respectively. The physical, chemical, and structural properties of nanofibers were studied using various advanced analytical techniques. The properties of isolated nanofibers were almost similar and comparable to those of commercial nanofibers. The surface charge densities were −94.0, −80.7, and −90.6 mV for the nanofibers of palm waste, cotton fibers, and filter paper, respectively. After membrane fabrication using vacuum and hot-pressing techniques, the characteristics of the membrane were analyzed. The results showed that the average pore size of the palm-waste membrane was 1.185 nm, while it was 1.875 nm for membrane from waste cotton fibers and filter paper. Congo red and methylene blue dyes were used as model solutions to understand the behavior of available functional groups and the surface ζ-potential of the membrane frameworks’ interaction. The membrane made from palm waste had the highest dye removal efficiency, and it was 23% for Congo red and 44% for methylene blue. This study provides insights into the challenges associated with the use of postconsumer textile and agricultural waste, which can be potentially used in high-performance liquid filtration devices for a more sustainable society. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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30 pages, 7426 KiB

Open AccessArticle

Cryo-Induced Cellulose-Based Nanogel from Elaeis guineensis for Antibiotic Delivery Platform

by Tasnim Hajidariyor, Nutchanon Nuntawad, Panadda Somsaen, Raninnart Prukdamrongchai, Harit Cherdchoo, Pattaraporn Posoknistakul, Pongtanawat Khemthong, Wanwitoo Wanmolee, Pariyapat Arjfuk, Pisut Pongchaikul, Navadol Laosiripojana, Kevin C.-W. Wu and Chularat Sakdaronnarong

Int. J. Mol. Sci. 2023, 24(2), 1230; https://doi.org/10.3390/ijms24021230 - 08 Jan 2023

Cited by 7 | Viewed by 1861

Abstract

Cryo-induced hydrogel from cellulose is a new class of biomaterials for drug delivery, cell delivery, bone and skin tissue engineering for cell proliferation and regeneration applications. This research aimed to synthesize cryo-induced hydrogel from cellulose and carboxymethyl cellulose (CMC) produced from empty bunch’s [...] Read more.

Cryo-induced hydrogel from cellulose is a new class of biomaterials for drug delivery, cell delivery, bone and skin tissue engineering for cell proliferation and regeneration applications. This research aimed to synthesize cryo-induced hydrogel from cellulose and carboxymethyl cellulose (CMC) produced from empty bunch’s cell wall of Elaeis guineensis. First, the experiment was to produce cellulose-rich material using hot-compressed water extraction followed by alkaline delignification and bleaching with H₂O₂. The obtained bleached EFB cellulose was used as the substrate for CMC, and the optimal condition with the highest degree of carboxyl substitution (DS) of 0.75 was achieved when varying NaOH and monochloroacetic acid concentration as well as etherification temperature using fractional factorial design. For cryogelation study, hydrogels were synthesized from cellulose, CMC and beta-cyclodextrin (β-CD) by dissolving cellulose-based matrix in a NaOH/urea system, and the cellulose (CEL) solution was frozen spontaneously at −40 °C followed by high speed mixing to loosen cellulose fibrils. Epichlorohydrin (ECH) and Polyethylene glycol diglycidyl ether (PEGDE) were used as a cross-linker. First, the ratio of cellulose and CMC with different amounts of ECH was investigated, and subsequently the proper ratio was further studied by adding different crosslinkers and matrices, i.e., CMC and β-CD. From the result, the ECH crosslinked CMC-CEL (E-CMC-CEL) gel had the highest swelling properties of 5105% with the average pore size of lyophilized hydrogel of 300 µm. In addition, E-CMC-CEL gel had the highest loading and release capability of tetracycline in buffer solution at pH 7.4 and 3.2. At pH 7.4, tetracycline loading and release properties of E-CMC-CEL gel were 65.85 mg g⁻¹ dry hydrogel and 46.48 mg g⁻¹ dry hydrogel (70.6% cumulative release), respectively. However, at pH 3.2, the loading and release capabilities of Tetracycline were moderately lower at 16.25 mg g⁻¹ dry hydrogel and 5.06 mg g⁻¹ dry hydrogel, respectively. The findings presented that E-CMC-CEL hydrogel was a suitable material for antibiotic tetracycline drug carrying platform providing successful inhibitory effect on Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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15 pages, 4698 KiB

Open AccessArticle

Functionalization of Polylactide with Multiple Tetraphenyethane Inifer Groups to Form PLA Block Copolymers with Vinyl Monomers

by Mateusz Grabowski, Bartłomiej Kost, Agnieszka Bodzioch and Melania Bednarek

Int. J. Mol. Sci. 2023, 24(1), 19; https://doi.org/10.3390/ijms24010019 - 20 Dec 2022

Cited by 2 | Viewed by 1301

Abstract

In the present contribution, a new strategy for preparing block copolymers of polylactide (PLA), a bio-derived polymer of increasing importance, is described. The method should lead to multiblock copolymers of lactide with vinyl monomers (VM), i.e., monomers that polymerize according to different mechanisms, [...] Read more.

In the present contribution, a new strategy for preparing block copolymers of polylactide (PLA), a bio-derived polymer of increasing importance, is described. The method should lead to multiblock copolymers of lactide with vinyl monomers (VM), i.e., monomers that polymerize according to different mechanisms, and is based on the introduction of multiple “inifer” (INItiator/transFER agent) groups into PLA’s structure. As an “inifer” group, tetraphenylethane (TPE, known to easily thermally dissociate to radicals) was incorporated into PLA chains using diisocyanate. PLA that contained TPE groups (PLA-PU) was characterized, and its ability to form initiating radicals was demonstrated by ESR measurements. PLA-PU was used as a “macroinifer” for the polymerization of acrylonitrile and styrene upon moderate heating (85 °C) of the PLA-PU in the presence of monomers. The formation of block copolymers PLA/PVM was confirmed by ¹H NMR, DOSY NMR, and FTIR spectroscopies and the SEC method. The prepared copolymers showed only one glass transition in DSC curves with T_g values higher than those of PLA-PU. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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11 pages, 2268 KiB

Open AccessArticle

Biocompatible Potato-Starch Electrolyte-Based Coplanar Gate-Type Artificial Synaptic Transistors on Paper Substrates

by Hyun-Sik Choi, Young-Jun Lee, Hamin Park and Won-Ju Cho

Int. J. Mol. Sci. 2022, 23(24), 15901; https://doi.org/10.3390/ijms232415901 - 14 Dec 2022

Cited by 6 | Viewed by 1592

Abstract

In this study, we propose the use of artificial synaptic transistors with coplanar-gate structures fabricated on paper substrates comprising biocompatible and low-cost potato-starch electrolyte and indium–gallium–zinc oxide (IGZO) channels. The electrical double layer (EDL) gating effect of potato-starch electrolytes enabled the emulation of [...] Read more.

In this study, we propose the use of artificial synaptic transistors with coplanar-gate structures fabricated on paper substrates comprising biocompatible and low-cost potato-starch electrolyte and indium–gallium–zinc oxide (IGZO) channels. The electrical double layer (EDL) gating effect of potato-starch electrolytes enabled the emulation of biological synaptic plasticity. Frequency dependence measurements of capacitance using a metal-insulator-metal capacitor configuration showed a 1.27 μF/cm² at a frequency of 10 Hz. Therefore, strong capacitive coupling was confirmed within the potato-starch electrolyte/IGZO channel interface owing to EDL formation because of internal proton migration. An electrical characteristics evaluation of the potato-starch EDL transistors through transfer and output curve resulted in counterclockwise hysteresis caused by proton migration in the electrolyte; the hysteresis window linearly increased with maximum gate voltage. A synaptic functionality evaluation with single-spike excitatory post-synaptic current (EPSC), paired-pulse facilitation (PPF), and multi-spike EPSC resulted in mimicking short-term synaptic plasticity and signal transmission in the biological neural network. Further, channel conductance modulation by repetitive presynaptic stimuli, comprising potentiation and depression pulses, enabled stable modulation of synaptic weights, thereby validating the long-term plasticity. Finally, recognition simulations on the Modified National Institute of Standards and Technology (MNIST) handwritten digit database yielded a 92% recognition rate, thereby demonstrating the applicability of the proposed synaptic device to the neuromorphic system. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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17 pages, 5019 KiB

Open AccessArticle

Sustainable Plant-Based Biopolymer Membranes for PEM Fuel Cells

by Songtao Li, George Cai, Songze Wu, Aniket Raut, William Borges, Priyanka R. Sharma, Sunil K. Sharma, Benjamin S. Hsiao and Miriam Rafailovich

Int. J. Mol. Sci. 2022, 23(23), 15245; https://doi.org/10.3390/ijms232315245 - 03 Dec 2022

Cited by 6 | Viewed by 2046

Abstract

Carboxycellulose nanofibers (CNFs) promise to be a sustainable and inexpensive alternative material for polymer electrolyte membranes compared to the expensive commercial Nafion membrane. However, its practical applications have been limited by its relatively low performance and reduced mechanical properties under typical operating conditions. [...] Read more.

Carboxycellulose nanofibers (CNFs) promise to be a sustainable and inexpensive alternative material for polymer electrolyte membranes compared to the expensive commercial Nafion membrane. However, its practical applications have been limited by its relatively low performance and reduced mechanical properties under typical operating conditions. In this study, carboxycellulose nanofibers were derived from wood pulp by TEMPO oxidation of the hydroxyl group present on the C6 position of the cellulose chain. Then, citric acid cross-linked CNF membranes were prepared by a solvent casting method to enhance performance. Results from FT-IR spectroscopy, ¹³C NMR spectroscopy, and XRD reveal a chemical cross-link between the citric acid and CNF, and the optimal fuel cell performance was obtained by cross-linking 70 mL of 0.20 wt % CNF suspension with 300 µL of 1.0 M citric acid solution. The membrane electrode assemblies (MEAs), operated in an oxygen atmosphere, exhibited the maximum power density of 27.7 mW cm⁻² and the maximum current density of 111.8 mA cm⁻² at 80 °C and 100% relative humidity (RH) for the citric acid cross-linked CNF membrane with 0.1 mg cm⁻² Pt loading on the anode and cathode, which is approximately 30 times and 22 times better, respectively, than the uncross-linked CNF film. A minimum activation energy of 0.27 eV is achieved with the best-performing citric acid cross-linked CNF membrane, and a proton conductivity of 9.4 mS cm⁻¹ is obtained at 80 °C. The surface morphology of carboxycellulose nanofibers and corresponding membranes were characterized by FIB/SEM, SEM/EDX, TEM, and AFM techniques. The effect of citric acid on the mechanical properties of the membrane was assessed by tensile strength DMA. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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13 pages, 6726 KiB

Open AccessArticle

Polysiloxane-Based Polyurethanes with High Strength and Recyclability

by Wencai Wang, Xueyang Bai, Siao Sun, Yangyang Gao, Fanzhu Li and Shikai Hu

Int. J. Mol. Sci. 2022, 23(20), 12613; https://doi.org/10.3390/ijms232012613 - 20 Oct 2022

Cited by 6 | Viewed by 2058

Abstract

Polysiloxanes have attracted considerable attention in biomedical engineering, owing to their inherent properties, including good flexibility and biocompatibility. However, their low mechanical strength limits their application scope. In this study, we synthesized a polysiloxane-based polyurethane by chemical copolymerization. A series of thermoplastic polysiloxane-polyurethanes [...] Read more.

Polysiloxanes have attracted considerable attention in biomedical engineering, owing to their inherent properties, including good flexibility and biocompatibility. However, their low mechanical strength limits their application scope. In this study, we synthesized a polysiloxane-based polyurethane by chemical copolymerization. A series of thermoplastic polysiloxane-polyurethanes (Si-TPUs) was synthesized using hydroxyl-terminated polydimethylsiloxane containing two carbamate groups at the tail of the polymer chains 4,4′-dicyclohexylmethane diisocyanate (HMDI) and 1,4-butanediol as raw materials. The effects of the hard-segment content and soft-segment number average molecular weight on the properties of the resulting TPUs were investigated. The prepared HMDI-based Si-TPUs exhibited good microphase separation, excellent mechanical properties, and acceptable repeatable processability. The tensile strength of SiTPU-2K-39 reached 21.5 MPa, which is significantly higher than that of other flexible polysiloxane materials. Moreover, the tensile strength and breaking elongation of SiTPU-2K-39 were maintained at 80.9% and 94.6%, respectively, after three cycles of regeneration. The Si-TPUs prepared in this work may potentially be used in gas separation, medical materials, antifouling coatings, and other applications. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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14 pages, 4076 KiB

Open AccessArticle

Synthesis of Lightweight Renewable Microwave-Absorbing Bio-Polyurethane/Fe₃O₄ Composite Foam: Structure Analysis and Absorption Mechanism

by Xiaoling Xu, Xiaoke Tian, Guangxu Bo, Xingjian Su, Jinyong Yan and Yunjun Yan

Int. J. Mol. Sci. 2022, 23(20), 12301; https://doi.org/10.3390/ijms232012301 - 14 Oct 2022

Cited by 5 | Viewed by 1385

Abstract

Sustainable renewable polymer foam used as a lightweight porous skeleton for microwave absorption is a novel strategy that can effectively solve the problems of the large surface density, high additive amount, and narrow absorbing band of absorbing materials. In this article, novel renewable [...] Read more.

Sustainable renewable polymer foam used as a lightweight porous skeleton for microwave absorption is a novel strategy that can effectively solve the problems of the large surface density, high additive amount, and narrow absorbing band of absorbing materials. In this article, novel renewable microwave-absorbing foams were prepared using Sapiumse biferum kernel oil-based polyurethane foam (BPUF) as porous matrix and Fe₃O₄-nanoparticles as magnetic absorbents. The microstructure and the microwave absorption performance, the structural effects on the properties, and electromagnetic mechanism of the magnetic BPUF (mBPUF) were systematically characterized and analyzed. The results show that the mBPUF displayed a porous hierarchical structure and was multi-interfacial, which provided a skeleton and matching layer for the Fe₃O₄ nanoparticles. The effective reflection loss (RL ≤ −10 dB) frequency of the mBPUF was from 4.16 GHz to 18 GHz with only 9 wt% content of Fe₃O₄ nanoparticles at a thickness of 1.5~5 mm. The surface density of the mBPUF coatings was less than 0.5 kg/cm² at a thickness of 1.8 mm. The lightweight characteristics and broadband absorption were attributed to the porous hierarchical structures and the dielectric combined with the magnetic loss effect. It indicates that the mBPUF is a prospective broadband-absorbing material in the field of lightweight stealth materials. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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24 pages, 9437 KiB

Open AccessArticle

Chitosan versus Carboxymethyl Chitosan Cryogels: Bacterial Colonization, Human Embryonic Kidney 293T Cell Culturing and Co-Culturing

by Andrey Boroda, Yuliya Privar, Mariya Maiorova, Irina Beleneva, Marina Eliseikina, Anna Skatova, Dmitry Marinin and Svetlana Bratskaya

Int. J. Mol. Sci. 2022, 23(20), 12276; https://doi.org/10.3390/ijms232012276 - 14 Oct 2022

Cited by 4 | Viewed by 1484

Abstract

The potential of chitosan and carboxymethyl chitosan (CMC) cryogels cross-linked with diglycidyl ether of 1,4-butandiol (BDDGE) and poly(ethylene glycol) (PEGDGE) have been compared in terms of 3D culturing HEK-293T cell line and preventing the bacterial colonization of the scaffolds. The first attempts to [...] Read more.

The potential of chitosan and carboxymethyl chitosan (CMC) cryogels cross-linked with diglycidyl ether of 1,4-butandiol (BDDGE) and poly(ethylene glycol) (PEGDGE) have been compared in terms of 3D culturing HEK-293T cell line and preventing the bacterial colonization of the scaffolds. The first attempts to apply cryogels for the 3D co-culturing of bacteria and human cells have been undertaken toward the development of new models of host–pathogen interactions and bioimplant-associated infections. Using a combination of scanning electron microscopy, confocal laser scanning microscopy, and flow cytometry, we have demonstrated that CMC cryogels provided microenvironment stimulating cell–cell interactions and the growth of tightly packed multicellular spheroids, while cell–substrate interactions dominated in both chitosan cryogels, despite a significant difference in swelling capacities and Young’s modulus of BDDGE- and PEGDGE-cross-linked scaffolds. Chitosan cryogels demonstrated only mild antimicrobial properties against Pseudomonas fluorescence, and could not prevent the formation of Staphylococcus aureus biofilm in DMEM media. CMC cryogels were more efficient in preventing the adhesion and colonization of both P. fluorescence and S. aureus on the surface, demonstrating antifouling properties rather than the ability to kill bacteria. The application of CMC cryogels to 3D co-culture HEK-293T spheroids with P. fluorescence revealed a higher resistance of human cells to bacterial toxins than in the 2D co-culture. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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17 pages, 4648 KiB

Open AccessArticle

Wheat Flour-Based Edible Films: Effect of Gluten on the Rheological Properties, Structure, and Film Characteristics

by Jing Wang, Xinyu Sun, Xingfeng Xu, Qingjie Sun, Man Li, Yanfei Wang and Fengwei Xie

Int. J. Mol. Sci. 2022, 23(19), 11668; https://doi.org/10.3390/ijms231911668 - 01 Oct 2022

Cited by 7 | Viewed by 2348

Abstract

This work investigates the structure, rheological properties, and film performance of wheat flour hydrocolloids and their comparison with that of a wheat starch (WS)–gluten blend system. The incorporation of gluten could decrease inter-chain hydrogen bonding of starch, thereby reducing the viscosity and solid-like [...] Read more.

This work investigates the structure, rheological properties, and film performance of wheat flour hydrocolloids and their comparison with that of a wheat starch (WS)–gluten blend system. The incorporation of gluten could decrease inter-chain hydrogen bonding of starch, thereby reducing the viscosity and solid-like behavior of the film-forming solution and improving the frequency-dependence, but reducing the surface smoothness, compactness, water vapor barrier performance, and mechanical properties of the films. However, good compatibility between starch and gluten could improve the density of self-similar structure, the processability of the film-forming solution, and film performance. The films based on wheat flours showed a denser film structure, better mechanical properties, and thermal stability that was no worse than that based on WS–gluten blends. The knowledge gained from this study could provide guidance to the development of other flour-based edible packaging materials, thereby promoting energy conservation and environmental protection. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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22 pages, 7215 KiB

Open AccessArticle

Silver Nanoparticles Biocomposite Films with Antimicrobial Activity: In Vitro and In Vivo Tests

by Anca Niculina Cadinoiu, Delia Mihaela Rata, Oana Maria Daraba, Daniela Luminita Ichim, Irina Popescu, Carmen Solcan and Gheorghe Solcan

Int. J. Mol. Sci. 2022, 23(18), 10671; https://doi.org/10.3390/ijms231810671 - 14 Sep 2022

Cited by 15 | Viewed by 1925

Abstract

Overuse of antimicrobials by the population has contributed to genetic modifications in bacteria and development of antimicrobial resistance, which is very difficult to combat nowadays. To solve this problem, it is necessary to develop new systems for the administration of antimicrobial active principles. [...] Read more.

Overuse of antimicrobials by the population has contributed to genetic modifications in bacteria and development of antimicrobial resistance, which is very difficult to combat nowadays. To solve this problem, it is necessary to develop new systems for the administration of antimicrobial active principles. Biocomposite systems containing silver nanoparticles can be a good medical alternative. In this context, the main objective of this study was to obtain a complex system in the form of a biocomposite film with antimicrobial properties based on chitosan, poly (vinyl alcohol) and silver nanoparticles. This new system was characterized from a structural and morphological point of view. The swelling degree, the mechanical properties and the efficiency of loading and release of an anti-inflammatory drug were also evaluated. The obtained biocomposite films are biocompatibles, this having been demonstrated by in vitro tests on HDFa cell lines, and have antimicrobial activity against S. aureus. The in vivo tests, carried out on rabbit subjects, highlighted the fact that signs of reduced fibrosis were specific to the C2P4.10.Ag1-IBF film sample, demonstrated by: intense expression of TNFAIP8 factors; as an anti-apoptotic marker, MHCII that favors immune cooperation among local cells; αSMA, which marks the presence of myofibroblasts involved in approaching the interepithelial spaces for epithelialization; and reduced expression of the Cox2 indicator of inflammation, Col I. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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31 pages, 887 KiB

Open AccessArticle

Comparative Study on the Models of Thermoreversible Gelation

by Fumihiko Tanaka

Int. J. Mol. Sci. 2022, 23(18), 10325; https://doi.org/10.3390/ijms231810325 - 07 Sep 2022

Cited by 1 | Viewed by 1081

Abstract

A critical survey on the various theoretical models of thermoreversible gelation, such as the droplet model of condensation, associated-particle model, site–bond percolation model, and adhesive hard sphere model, is presented, with a focus on the nature of the phase transition predicted by them. [...] Read more.

A critical survey on the various theoretical models of thermoreversible gelation, such as the droplet model of condensation, associated-particle model, site–bond percolation model, and adhesive hard sphere model, is presented, with a focus on the nature of the phase transition predicted by them. On the basis of the classical tree statistics of gelation, combined with a thermodynamic theory of associating polymer solutions, it is shown that, within the mean-field description, the thermoreversible gelation of polyfunctional molecules is a third-order phase transition analogous to the Bose–Einstein condensation of an ideal Bose gas. It is condensation without surface tension. The osmotic compressibility is continuous, but its derivative with respect to the concentration of the functional molecule reveals a discontinuity at the sol–gel transition point. The width of the discontinuity is directly related to the amplitude of the divergent term in the weight-average molecular weight of the cross-linked three-dimensional polymers. The solution remains homogeneous in the position space, but separates into two phases in the momentum space; particles with finite translational momentum (sol) and a network with zero translational momentum (gel) coexist in a spatially homogeneous state. Experimental methods used to detect the singularity at the sol–gel transition point are suggested. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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19 pages, 3944 KiB

Open AccessArticle

Property and Stability of Astaxanthin Emulsion Based on Pickering Emulsion Templating with Zein and Sodium Alginate as Stabilizer

by Yan Xu, Zhe Jia, Jiaxing Wang, Jipeng Sun and Ru Song

Int. J. Mol. Sci. 2022, 23(16), 9386; https://doi.org/10.3390/ijms23169386 - 20 Aug 2022

Cited by 3 | Viewed by 2099

Abstract

Astaxanthin loaded Pickering emulsion with zein/sodium alginate (SA) as a stabilizer (named as APEs) was developed, and its structure and stability were characterized. The encapsulation efficiency of astaxanthin (Asta) in APEs was up to 86.7 ± 3.8%, with a mean particle size of [...] Read more.

Astaxanthin loaded Pickering emulsion with zein/sodium alginate (SA) as a stabilizer (named as APEs) was developed, and its structure and stability were characterized. The encapsulation efficiency of astaxanthin (Asta) in APEs was up to 86.7 ± 3.8%, with a mean particle size of 4.763 μm. Freeze-dried APEs showed particles stacked together under scanning electronic microscope; whereas dispersed spherical nanoparticles were observed in APEs dilution under transmission electron microscope images. Confocal laser scanning microscope images indicated that zein particles loaded with Asta were aggregated with SA coating. X-ray diffraction patterns and Fourier transform infrared spectra results showed that intermolecular hydrogen bonding, electrostatic attraction and hydrophobic effect were involved in APEs formation. APEs demonstrated non-Newtonian shear-thinning behavior and fit well to the Cross model. Compared to bare Asta extract, APEs maintained high Asta retention and antioxidant activity when heated from 50 to 10 °C. APEs showed different stability at pH (3.0–11.0) and Na⁺, K⁺, Ca²⁺, Cu²⁺ and Fe²⁺ conditions by visual, zeta potential and polydispersity index measurements. Additionally, the first order kinetics fit well to describe APEs degradation at pH 3.0 to 9.0, Na⁺, and K⁺ conditions. Our results suggest the potential application of Asta-loaded Pickering emulsion in food systems as a fortified additive. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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19 pages, 22587 KiB

Open AccessArticle

Preparation and Characterization of High Mechanical Strength Chitosan/Oxidized Tannic Acid Composite Film with Schiff Base and Hydrogen Bond Crosslinking

by Zhiyong Qin, Youjia Huang, Siyu Xiao, Haoyu Zhang, Yunlong Lu and Kaijie Xu

Int. J. Mol. Sci. 2022, 23(16), 9284; https://doi.org/10.3390/ijms23169284 - 18 Aug 2022

Cited by 10 | Viewed by 2775

Abstract

Chitosan-based composite films with good biodegradability, biocompatibility, and sustainability are extensively employed in the field of food packaging. In this study, novel chitosan/tannic acid (CTA) and chitosan/oxidized tannic acid (COTA) composite films with excellent mechanical and antibacterial properties were prepared using a tape [...] Read more.

Chitosan-based composite films with good biodegradability, biocompatibility, and sustainability are extensively employed in the field of food packaging. In this study, novel chitosan/tannic acid (CTA) and chitosan/oxidized tannic acid (COTA) composite films with excellent mechanical and antibacterial properties were prepared using a tape casting method. The results showed that, when 20% tannic acid (TA) was added, the tensile strength of the CTA composite film was 80.7 MPa, which was 89.4% higher than that of the pure chitosan (CS) film. TA was oxidized to oxidized tannic acid (OTA) with laccase, and the phenolic hydroxyl groups were oxidized to an o-quinone structure. With the addition of OTA, a Schiff base reaction between the OTA and CS occurred, and a dual network structure consisting of a chemical bond and hydrogen bond was constructed, which further improved the mechanical properties. The tensile strength of 3% COTA composite film was increased by 97.2% compared to that of pure CS film. Furthermore, these CTA films with significant antibacterial effects against Escherichia coli (E. coli) are likely to find uses in food packaging applications. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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20 pages, 5431 KiB

Open AccessArticle

Removal of an Azo Dye from Wastewater through the Use of Two Technologies: Magnetic Cyclodextrin Polymers and Pulsed Light

by María Isabel Rodríguez-López, José Antonio Pellicer, Teresa Gómez-Morte, David Auñón, Vicente M. Gómez-López, María José Yáñez-Gascón, Ángel Gil-Izquierdo, José Pedro Cerón-Carrasco, Grégorio Crini, Estrella Núñez-Delicado and José Antonio Gabaldón

Int. J. Mol. Sci. 2022, 23(15), 8406; https://doi.org/10.3390/ijms23158406 - 29 Jul 2022

Cited by 12 | Viewed by 1787

Abstract

Water pollution by dyes is a huge environmental problem; there is a necessity to produce new decolorization methods that are effective, cost-attractive, and acceptable in industrial use. Magnetic cyclodextrin polymers offer the advantage of easy separation from the dye solution. In this work, [...] Read more.

Water pollution by dyes is a huge environmental problem; there is a necessity to produce new decolorization methods that are effective, cost-attractive, and acceptable in industrial use. Magnetic cyclodextrin polymers offer the advantage of easy separation from the dye solution. In this work, the β-CD-EPI-magnetic (β-cyclodextrin-epichlorohydrin) polymer was synthesized, characterized, and tested for removal of the azo dye Direct Red 83:1 from water, and the fraction of non-adsorbed dye was degraded by an advanced oxidation process. The polymer was characterized in terms of the particle size distribution and surface morphology (FE-SEM), elemental analysis (EA), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), infrared spectrophotometry (IR), and X-ray powder diffraction (XRD). The reported results hint that 0.5 g and pH 5.0 were the best conditions to carry out both kinetic and isotherm models. A 30 min contact time was needed to reach equilibrium with a qmax of 32.0 mg/g. The results indicated that the pseudo-second-order and intraparticle diffusion models were involved in the assembly of Direct Red 83:1 onto the magnetic adsorbent. Regarding the isotherms discussed, the Freundlich model correctly reproduced the experimental data so that adsorption was confirmed to take place onto heterogeneous surfaces. The calculation of the thermodynamic parameters further demonstrates the spontaneous character of the adsorption phenomena (ΔG° = −27,556.9 J/mol) and endothermic phenomena (ΔH° = 8757.1 J/mol) at 25 °C. Furthermore, a good reusability of the polymer was evidenced after six cycles of regeneration, with a negligible decline in the adsorption extent (10%) regarding its initial capacity. Finally, the residual dye in solution after treatment with magnetic adsorbents was degraded by using an advanced oxidation process (AOP) with pulsed light and hydrogen peroxide (343 mg/L); >90% of the dye was degraded after receiving a fluence of 118 J/cm²; the discoloration followed a pseudo first-order kinetics where the degradation rate was 0.0196 cm²/J. The newly synthesized β-CD-EPI-magnetic polymer exhibited good adsorption properties and separability from water which, when complemented with a pulsed light-AOP, may offer a good alternative to remove dyes such as Direct Red 83:1 from water. It allows for the reuse of both the polymer and the dye in the dyeing process. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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21 pages, 6574 KiB

Open AccessArticle

Electrospun Membranes Designed for Burst Release of New Gold-Complexes Inducing Apoptosis of Melanoma Cells

by Liberata Guadagno, Marialuigia Raimondo, Luigi Vertuccio, Erwin Pavel Lamparelli, Maria Camilla Ciardulli, Pasquale Longo, Annaluisa Mariconda, Giovanna Della Porta and Raffaele Longo

Int. J. Mol. Sci. 2022, 23(13), 7147; https://doi.org/10.3390/ijms23137147 - 27 Jun 2022

Cited by 10 | Viewed by 1689

Abstract

Two non-commercial metallic Au-based complexes were tested against one of the most aggressive malignant melanomas of the skin (MeWo cells), through cell viability and time-lapse live-cell imaging system assays. The tests with the complexes were carried out both in the form of free [...] Read more.

Two non-commercial metallic Au-based complexes were tested against one of the most aggressive malignant melanomas of the skin (MeWo cells), through cell viability and time-lapse live-cell imaging system assays. The tests with the complexes were carried out both in the form of free metallic complexes, directly in contact with the MeWo cell line culture, and embedded in fibers of Polycaprolactone (PCL) membranes produced by the electrospinning technique. Membranes functionalized with complexes were prepared to evaluate the efficiency of the membranes against the melanoma cells and therefore their feasibility in the application as an antitumoral patch for topical use. Both series of tests highlighted a very effective antitumoral activity, manifesting a very relevant cell viability inhibition after both 24 h and 48 h. In the case of the AuM1 complex at the concentration of 20 mM, melanoma cells completely died in this short period of time. A mortality of around 70% was detected from the tests performed using the membranes functionalized with AuM1 complex at a very low concentration (3 wt.%), even after 24 h of the contact period. The synthesized complexes also manifest high selectivity with respect to the MeWo cells. The peculiar structural and morphological organization of the nanofibers constituting the membranes allows for a very effective antitumoral activity in the first 3 h of treatment. Experimental points of the release profiles were perfectly fitted with theoretical curves, which easily allow interpretation of the kinetic phenomena occurring in the release of the synthesized complexes in the chosen medium. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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26 pages, 6567 KiB

Open AccessArticle

Degradation by Electron Beam Irradiation of Some Composites Based on Natural Rubber Reinforced with Mineral and Organic Fillers

by Elena Manaila, Gabriela Craciun, Daniel Ighigeanu, Ion Bogdan Lungu, Marius Daniel Dumitru Grivei and Maria Daniela Stelescu

Int. J. Mol. Sci. 2022, 23(13), 6925; https://doi.org/10.3390/ijms23136925 - 22 Jun 2022

Cited by 7 | Viewed by 1700

Abstract

Composites based on natural rubber reinforced with mineral (precipitated silica and chalk) and organic (sawdust and hemp) fillers in amount of 50 phr were obtained by peroxide cross-linking in the presence of trimethylolpropane trimethacrylate and irradiated by electron beam in the dose range [...] Read more.

Composites based on natural rubber reinforced with mineral (precipitated silica and chalk) and organic (sawdust and hemp) fillers in amount of 50 phr were obtained by peroxide cross-linking in the presence of trimethylolpropane trimethacrylate and irradiated by electron beam in the dose range of 150 and 450 kGy with the purpose of degradation. The composites mechanical characteristics, gel fraction, cross-linking degree, water uptake and weight loss in water and toluene were evaluated by specific analysis. The changes in structure and morphology were also studied by Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. Based on the results obtained in the structural analysis, possible mechanisms specific to degradation are proposed. The increasing of irradiation dose to 450 kGy produced larger agglomerated structures, cracks and micro voids on the surface, as a result of the degradation process. This is consistent with that the increasing of irradiation dose to 450 kGy leads to a decrease in crosslinking and gel fraction but also drastic changes in mechanical properties specific to the composites’ degradation processes. The irradiation of composites reinforced with organic fillers lead to the formation of specific degradation compounds of both natural rubber and cellulose (aldehydes, ketones, carboxylic acids, compounds with small macromolecules). In the case of the composites reinforced with mineral fillers the degradation can occur by the cleavage of hydrogen bonds formed between precipitated silica or chalk particles and polymeric matrix also. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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12 pages, 4067 KiB

Open AccessArticle

Bio-Based Polyurethane and Its Composites towards High Damping Properties

by Shikai Hu, Yaowen Wu, Guoqing Fu, Tao Shou, Mengyao Zhai, Dexian Yin and Xiuying Zhao

Int. J. Mol. Sci. 2022, 23(12), 6618; https://doi.org/10.3390/ijms23126618 - 14 Jun 2022

Cited by 10 | Viewed by 1842

Abstract

The operation of mechanical equipment inevitably generates vibrations and noise, which are harmful to not only the human body but also to the equipment in use. Damping materials, which can convert mechanical energy into thermal energy, possess excellent damping properties in the glass [...] Read more.

The operation of mechanical equipment inevitably generates vibrations and noise, which are harmful to not only the human body but also to the equipment in use. Damping materials, which can convert mechanical energy into thermal energy, possess excellent damping properties in the glass transition region and can alleviate the problems caused by vibration and noise. However, these materials mainly rely on petroleum-based resources, and their glass transition temperatures (T_g) are lower than room temperature. Therefore, bio-based materials with high damping properties at room temperature must be designed for sustainable development. Herein, we demonstrate the fabrication of bio-based millable polyurethane (BMPU)/hindered phenol composites that could overcome the challenges of sustainable development and exhibit high damping properties at room temperature. BMPUs with a high T_g were prepared from modified poly (lactic acid)-based polyols, the unsaturated chain extender trimethylolpropane diallylether, and 4,4′-diphenylmethane diisocyanate, and 3,9-Bis-{1,1-dimethyl-2[β-(3-tert-butyl-4-hydroxy-5-methylphenyl-)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro [5,5]-undecane (AO-80) was added to prepare BMPU/AO-80 composites. Finally, the properties of the BMPUs and BMPU/AO-80 composites were systematically evaluated. After adding 30 phr of AO-80, the Tg and maximum loss factor (tan δ_max) of BMPU/AO-80 composites increased from 7.8 °C to 13.5 °C and from 1.4 to 2.0, respectively. The tan δ_max showed an improvement of 43%. Compared with other polyurethanes, the prepared BMPU/AO-80 composites exhibited higher damping properties at room temperature. This study proposes a new strategy to reduce society’s current dependence on fossil resources and design materials featuring high damping properties from sustainable raw materials. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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Review

Jump to: Editorial, Research

29 pages, 3151 KiB

Open AccessReview

The Advancement of Biodegradable Polyesters as Delivery Systems for Camptothecin and Its Analogues—A Status Report

by Katarzyna Strzelecka, Urszula Piotrowska, Marcin Sobczak and Ewa Oledzka

Int. J. Mol. Sci. 2023, 24(2), 1053; https://doi.org/10.3390/ijms24021053 - 05 Jan 2023

Cited by 4 | Viewed by 2479

Abstract

Camptothecin (CPT) has demonstrated antitumor activity in lung, ovarian, breast, pancreas, and stomach cancers. However, this drug, like many other potent anticancer agents, is extremely water-insoluble. Furthermore, pharmacology studies have revealed that prolonged schedules must be administered continuously. For these reasons, several of [...] Read more.

Camptothecin (CPT) has demonstrated antitumor activity in lung, ovarian, breast, pancreas, and stomach cancers. However, this drug, like many other potent anticancer agents, is extremely water-insoluble. Furthermore, pharmacology studies have revealed that prolonged schedules must be administered continuously. For these reasons, several of its water-soluble analogues, prodrugs, and macromolecular conjugates have been synthesized, and various formulation approaches have been investigated. Biodegradable polyesters have gained popularity in cancer treatment in recent years. A number of biodegradable polymeric drug delivery systems (DDSs), designed for localized and systemic administration of therapeutic agents, as well as tumor-targeting macromolecules, have entered clinical trials, demonstrating the importance of biodegradable polyesters in cancer therapy. Biodegradable polyester-based DDSs have the potential to deliver the payload to the target while also increasing drug availability at intended site. The systemic toxicity and serious side-effects associated with conventional cancer therapies can be significantly reduced with targeted polymeric systems. This review elaborates on the use of biodegradable polyesters in the delivery of CPT and its analogues. The design of various DDSs based on biodegradable polyesters has been described, with the drug either adsorbed on the polymer’s surface or encapsulated within its macrostructure, as well as those in which a hydrolyzed chemical bond is formed between the active substance and the polymer chain. The data related to the type of DDSs, the kind of linkage, and the details of in vitro and in vivo studies are included. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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12 pages, 1222 KiB

Open AccessReview

Antimicrobial Peptides Mediate Apoptosis by Changing Mitochondrial Membrane Permeability

by Hongji Wang, Chaowen Zhang, Mengnan Li, Chaoran Liu, Jingyi Wang, Xuan Ou and Yuzhu Han

Int. J. Mol. Sci. 2022, 23(21), 12732; https://doi.org/10.3390/ijms232112732 - 22 Oct 2022

Cited by 10 | Viewed by 2329

Abstract

Changes in mitochondrial membrane permeability are closely associated with mitochondria-mediated apoptosis. Antimicrobial peptides (AMPs), which have been found to enter cells to exert physiological effects, cause damage to the mitochondria. This paper reviews the molecular mechanisms of AMP-mediated apoptosis by changing the permeability [...] Read more.

Changes in mitochondrial membrane permeability are closely associated with mitochondria-mediated apoptosis. Antimicrobial peptides (AMPs), which have been found to enter cells to exert physiological effects, cause damage to the mitochondria. This paper reviews the molecular mechanisms of AMP-mediated apoptosis by changing the permeability of the mitochondrial membrane through three pathways: the outer mitochondrial membrane (OMM), inner mitochondrial membrane (IMM), and mitochondrial permeability transition pore (MPTP). The roles of AMPs in inducing changes in membrane permeability and apoptosis are also discussed. Combined with recent research results, the possible application prospects of AMPs are proposed to provide a theoretical reference for the development of AMPs as therapeutic agents for human diseases. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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19 pages, 2572 KiB

Open AccessReview

PMMA-Based Nanocomposites for Odontology Applications: A State-of-the-Art

by Ana M. Díez-Pascual

Int. J. Mol. Sci. 2022, 23(18), 10288; https://doi.org/10.3390/ijms231810288 - 07 Sep 2022

Cited by 23 | Viewed by 3864

Abstract

Polymethyl methacrylate (PMMA), a well-known polymer of the methacrylate family, is extensively used in biomedicine, particularly in odontological applications including artificial teeth, dentures and denture bases, obturators, provisional or permanent crowns, and so forth. The exceptional PMMA properties, including aesthetics, inexpensiveness, simple manipulation, [...] Read more.

Polymethyl methacrylate (PMMA), a well-known polymer of the methacrylate family, is extensively used in biomedicine, particularly in odontological applications including artificial teeth, dentures and denture bases, obturators, provisional or permanent crowns, and so forth. The exceptional PMMA properties, including aesthetics, inexpensiveness, simple manipulation, low density, and adjustable mechanical properties, make it a perfect candidate in the field of dentistry. However, it presents some deficiencies, including weakness regarding hydrolytic degradation, poor fracture toughness, and a lack of antibacterial activity. To further enhance its properties and solve these drawbacks, different approaches can be performed, including the incorporation of nanofillers. In this regard, different types of metallic nanoparticles, metal oxide nanofillers, and carbon-based nanomaterials have been recently integrated into PMMA matrices with the aim to reduce water absorption and improve their performance, namely their thermal and flexural properties. In this review, recent studies regarding the development of PMMA-based nanocomposites for odontology applications are summarized and future perspectives are highlighted. Full article

(This article belongs to the Special Issue Biopolymer Composites 2022)

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