Research

12 pages, 1862 KiB

Open AccessArticle

Towards Understanding the Role of Surface Gas Nanostructures: Effect of Temperature Difference Pretreatment on Wetting and Flotation of Sulfide Minerals and Pb-Zn Ore

by Yuri Mikhlin, Anton Karacharov, Sergey Vorobyev, Alexander Romanchenko, Maxim Likhatski, Svetlana Antsiferova and Svetlana Markosyan

Nanomaterials 2020, 10(7), 1362; https://doi.org/10.3390/nano10071362 - 12 Jul 2020

Cited by 8 | Viewed by 2301

Abstract

Surface nanobubbles at hydrophobic interfaces now attract much attention in various fields but their role in wetting-related phenomena is still unclear. Herein, we report the effect of a preliminary contact of “hot” solids with cold water previously proposed for generation of surface nanobubbles, [...] Read more.

Surface nanobubbles at hydrophobic interfaces now attract much attention in various fields but their role in wetting-related phenomena is still unclear. Herein, we report the effect of a preliminary contact of “hot” solids with cold water previously proposed for generation of surface nanobubbles, on wettability of compact materials and flotation of particulate galena (PbS), sphalerite (ZnS), and Pb-Zn sulfide ore. Atomic force microscopy was applied to visualize the nanobubbles at galena crystals heated in air and contacted with cold water; X-ray photoelectron spectroscopy was used to characterize the surface composition of minerals. Contact angles measured with the sessile drop of cold water were found to increase when enhancing the support temperature from 0 to 80 °C for sphalerite and silica, and to pass a maximum at 40–60 °C for galena and pyrite (FeS₂) probably due to oxidation of sulfides. The temperature pretreatment depressed the recovery of sulfides in collectorless schemes and improved the potassium butyl xanthate-assisted flotation both for single minerals and Gorevskoye Pb-Zn ore. The results suggest that the surface nanobubbles prepared using the temperature difference promote flotation if minerals are rather hydrophobic and insignificantly oxidized, so the addition of collector and activator (for sphalerite) is necessary. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

► Show Figures

Figure 1

14 pages, 2880 KiB

Open AccessArticle

Three-Dimensional Printed Polylactic Acid (PLA) Surgical Retractors with Sonochemically Immobilized Silver Nanoparticles: The Next Generation of Low-Cost Antimicrobial Surgery Equipment

by Lazaros Tzounis, Petros I. Bangeas, Aristomenis Exadaktylos, Markos Petousis and Nectarios Vidakis

Nanomaterials 2020, 10(5), 985; https://doi.org/10.3390/nano10050985 - 21 May 2020

Cited by 34 | Viewed by 3138

Abstract

A versatile method is reported for the manufacturing of antimicrobial (AM) surgery equipment utilising fused deposition modelling (FDM), three-dimensional (3D) printing and sonochemistry thin-film deposition technology. A surgical retractor was replicated from a commercial polylactic acid (PLA) thermoplastic filament, while a thin layer [...] Read more.

A versatile method is reported for the manufacturing of antimicrobial (AM) surgery equipment utilising fused deposition modelling (FDM), three-dimensional (3D) printing and sonochemistry thin-film deposition technology. A surgical retractor was replicated from a commercial polylactic acid (PLA) thermoplastic filament, while a thin layer of silver (Ag) nanoparticles (NPs) was developed via a simple and scalable sonochemical deposition method. The PLA retractor covered with Ag NPs (PLA@Ag) exhibited vigorous AM properties examined by a reduction in Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli) bacteria viability (%) experiments at 30, 60 and 120 min duration of contact (p < 0.05). Scanning electron microscopy (SEM) showed the surface morphology of bare PLA and PLA@Ag retractor, revealing a homogeneous and full surface coverage of Ag NPs. X-Ray diffraction (XRD) analysis indicated the crystallinity of Ag nanocoating. Ultraviolent-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM) highlighted the AgNP plasmonic optical responses and average particle size of 31.08 ± 6.68 nm. TEM images of the PLA@Ag crossection demonstrated the thickness of the deposited Ag nanolayer, as well as an observed tendency of AgNPs to penetrate though the outer surface of PLA. The combination of 3D printing and sonochemistry technology could open new avenues in the manufacturing of low-cost and on-demand antimicrobial surgery equipment. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

► Show Figures

Graphical abstract

13 pages, 2453 KiB

Open AccessArticle

Structural Modification of Nanomicelles through Phosphatidylcholine: The Enhanced Drug-Loading Capacity and Anticancer Activity of Celecoxib-Casein Nanoparticles for the Intravenous Delivery of Celecoxib

by Liuli Xv, Xinxin Qian, Yan Wang, Chenghuan Yu, Dingkui Qin, Yahui Zhang, Peng Jin and Qizhen Du

Nanomaterials 2020, 10(3), 451; https://doi.org/10.3390/nano10030451 - 02 Mar 2020

Cited by 16 | Viewed by 2997

Abstract

This study aims to stabilize loaded celecoxib (CX) by modifying the structure of casein nanoparticles through phosphatidylcholine. The results show that Egg yolk phosphatidylcholine PC_98T (PC) significantly increased the stability of CX-PC-casein nanoparticles (NPs) (192.6 nm) from 5 min (CX-β-casein-NPs) to 2.5 [...] Read more.

This study aims to stabilize loaded celecoxib (CX) by modifying the structure of casein nanoparticles through phosphatidylcholine. The results show that Egg yolk phosphatidylcholine PC_98T (PC) significantly increased the stability of CX-PC-casein nanoparticles (NPs) (192.6 nm) from 5 min (CX-β-casein-NPs) to 2.5 h at 37 °C. In addition, the resuspended freeze-dried NPs (202.4 nm) remained stable for 2.5 h. Scanning electron microscopy indicated that PC may block the micropore structures in nanoparticles by ultrasonic treatment and hence improve the physicochemical stability of CX-PC-casein-NPs. The stability of the NPs was positively correlated with their inhibiting ability for human malignant melanoma A375 cells. The structural modification of CX-PC-casein-NPs resulted in an increased intracellular uptake of CX by 2.4 times than that of the unmodified ones. The pharmacokinetic study showed that the Area Under Curve (AUC) of the CX-PC-casein-NPs was 2.9-fold higher in rats than that of the original casein nanoparticles. When CX-PC-casein-NPs were intravenously administrated to mice implanted with A375 tumors (CX dose = 16 mg/kg bodyweight), the tumor inhibition rate reached 56.2%, which was comparable to that of paclitaxel (57.3%) at a dose of 4 mg/kg bodyweight. Our results confirm that the structural modification of CX-PC-casein-NPs can effectively prolong the remaining time of specific drugs, and may provide a potential strategy for cancer treatment. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

► Show Figures

Graphical abstract

11 pages, 2900 KiB

Open AccessArticle

Actinide and Lanthanide Adsorption onto Hierarchically Porous Carbons Beads: A High Surface Affinity for Pu

by Vittorio Luca, Devlet G. Sizgek, Erden Sizgek, Guilhem Arrachart, Cyrielle Rey, Nicholas Scales, Zaynab Aly and Glenna L. Drisko

Nanomaterials 2019, 9(10), 1464; https://doi.org/10.3390/nano9101464 - 16 Oct 2019

Cited by 8 | Viewed by 2963

Abstract

Structured carbon adsorbents were prepared by carbonizing macroporous polyacrylonitrile beads whose pores were lined with a mesoporous phenolic resin. After activation, the beads were tested for minor actinide (Np and Am), major actinide (Pu and U) and lanthanide (Gd) adsorption in varying acidic [...] Read more.

Structured carbon adsorbents were prepared by carbonizing macroporous polyacrylonitrile beads whose pores were lined with a mesoporous phenolic resin. After activation, the beads were tested for minor actinide (Np and Am), major actinide (Pu and U) and lanthanide (Gd) adsorption in varying acidic media. The activation of the carbon with ammonium persulfate increased the surface adsorption of the actinides, while decreasing lanthanide adsorption. These beads had a pH region where Pu could be selectively extracted. Pu is one of the longest lived, abundant and most radiotoxic components of spent nuclear fuel and thus, there is an urgent need to increase its security of storage. As carbon has a low neutron absorption cross-section, these beads present an affordable, efficient and safe means for Pu separation from nuclear waste. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

► Show Figures

Graphical abstract

13 pages, 2009 KiB

Open AccessArticle

Hydrothermal Fabrication of Spindle-Shaped ZnO/Palygorskite Nanocomposites Using Nonionic Surfactant for Enhancement of Antibacterial Activity

by Aiping Hui, Shuqing Dong, Yuru Kang, Yanmin Zhou and Aiqin Wang

Nanomaterials 2019, 9(10), 1453; https://doi.org/10.3390/nano9101453 - 13 Oct 2019

Cited by 19 | Viewed by 3083

Abstract

In order to improve the antibacterial performance of natural palygorskite, spindle-like ZnO/palygorskite (ZnO/PAL) nanocomposites with controllable growth of ZnO on the surface of PAL were prepared in the presence of non-ionic surfactants using an easy-to-operate hydrothermal method. The obtained ZnO/PAL nanocomposites have a [...] Read more.

In order to improve the antibacterial performance of natural palygorskite, spindle-like ZnO/palygorskite (ZnO/PAL) nanocomposites with controllable growth of ZnO on the surface of PAL were prepared in the presence of non-ionic surfactants using an easy-to-operate hydrothermal method. The obtained ZnO/PAL nanocomposites have a novel and special spindle-shaped structure and good antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and are also low cost. The minimum inhibitory concentrations of ZnO/PAL nanocomposites toward E. coli and S. aureus reached 1.5 and 5 mg/mL, respectively. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

► Show Figures

Figure 1

9 pages, 1378 KiB

Open AccessArticle

Increasing Silver Nanowire Network Stability through Small Molecule Passivation

by Alexandra Madeira, Marie Plissonneau, Laurent Servant, Irene A. Goldthorpe and Mona Tréguer-Delapierre

Nanomaterials 2019, 9(6), 899; https://doi.org/10.3390/nano9060899 - 20 Jun 2019

Cited by 27 | Viewed by 3789

Abstract

Silver nanowire (AgNW) transparent electrodes show promise as an alternative to indium tin oxide (ITO). However, these nanowire electrodes degrade in air, leading to significant resistance increases. We show that passivating the nanowire surfaces with small organic molecules of 11-mercaptoundecanoic acid (MUA) does [...] Read more.

Silver nanowire (AgNW) transparent electrodes show promise as an alternative to indium tin oxide (ITO). However, these nanowire electrodes degrade in air, leading to significant resistance increases. We show that passivating the nanowire surfaces with small organic molecules of 11-mercaptoundecanoic acid (MUA) does not affect electrode transparency contrary to typical passivation films, and is inexpensive and simple to deposit. The sheet resistance of a 32 nm diameter silver nanowire network coated with MUA increases by only 12% over 120 days when exposed to atmospheric conditions but kept in the dark. The increase is larger when exposed to daylight (588%), but is still nearly two orders of magnitude lower than the resistance increase of unpassivated networks. The difference between the experiments performed under daylight versus the dark exemplifies the importance of testing passivation materials under light exposure. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

► Show Figures

Graphical abstract

22 pages, 2652 KiB

Open AccessArticle

Large-Area Biomolecule Nanopatterns on Diblock Copolymer Surfaces for Cell Adhesion Studies

by Verónica Hortigüela, Enara Larrañaga, Anna Lagunas, Gerardo A. Acosta, Fernando Albericio, Jordi Andilla, Pablo Loza-Alvarez and Elena Martínez

Nanomaterials 2019, 9(4), 579; https://doi.org/10.3390/nano9040579 - 09 Apr 2019

Cited by 4 | Viewed by 7882

Abstract

Cell membrane receptors bind to extracellular ligands, triggering intracellular signal transduction pathways that result in specific cell function. Some receptors require to be associated forming clusters for effective signaling. Increasing evidences suggest that receptor clustering is subjected to spatially controlled ligand distribution at [...] Read more.

Cell membrane receptors bind to extracellular ligands, triggering intracellular signal transduction pathways that result in specific cell function. Some receptors require to be associated forming clusters for effective signaling. Increasing evidences suggest that receptor clustering is subjected to spatially controlled ligand distribution at the nanoscale. Herein we present a method to produce in an easy, straightforward process, nanopatterns of biomolecular ligands to study ligand–receptor processes involving multivalent interactions. We based our platform in self-assembled diblock copolymers composed of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) that form PMMA nanodomains in a closed-packed hexagonal arrangement. Upon PMMA selective functionalization, biomolecular nanopatterns over large areas are produced. Nanopattern size and spacing can be controlled by the composition of the block-copolymer selected. Nanopatterns of cell adhesive peptides of different size and spacing were produced, and their impact in integrin receptor clustering and the formation of cell focal adhesions was studied. Cells on ligand nanopatterns showed an increased number of focal contacts, which were, in turn, more matured than those found in cells cultured on randomly presenting ligands. These findings suggest that our methodology is a suitable, versatile tool to study and control receptor clustering signaling and downstream cell behavior through a surface-based ligand patterning technique. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

► Show Figures

Figure 1

13 pages, 4068 KiB

Open AccessArticle

Carbon Fibers Encapsulated with Nano-Copper: A Core–Shell Structured Composite for Antibacterial and Electromagnetic Interference Shielding Applications

by Yue Jiao, Caichao Wan, Wenbo Zhang, Wenhui Bao and Jian Li

Nanomaterials 2019, 9(3), 460; https://doi.org/10.3390/nano9030460 - 19 Mar 2019

Cited by 35 | Viewed by 4830

Abstract

A facile and scalable two-step method (including pyrolysis and magnetron sputtering) is created to prepare a core–shell structured composite consisting of cotton-derived carbon fibers (CDCFs) and nano-copper. Excellent hydrophobicity (water contact angle = 144°) and outstanding antibacterial activity against Escherichia coli and Staphylococcus [...] Read more.

A facile and scalable two-step method (including pyrolysis and magnetron sputtering) is created to prepare a core–shell structured composite consisting of cotton-derived carbon fibers (CDCFs) and nano-copper. Excellent hydrophobicity (water contact angle = 144°) and outstanding antibacterial activity against Escherichia coli and Staphylococcus aureus (antibacterial ratios of >92%) are achieved for the composite owing to the composition transformation from cellulose to carbon and nano-size effects as well as strong oxidizing ability of oxygen reactive radicals from interactions of nano-Cu with sulfhydryl groups of enzymes. Moreover, the core–shell material with high electrical conductivity induces the interfacial polarization loss and conduction loss, contributing to a high electromagnetic interference (EMI) shielding effectiveness of 29.3 dB. Consequently, this flexible and multi-purpose hybrid of nano-copper/CDCFs may be useful for numerous applications like self-cleaning wall cladding, EMI shielding layer and antibacterial products. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

► Show Figures

Graphical abstract

10 pages, 940 KiB

Open AccessArticle

Size Limit and Energy Analysis of Nanoparticles during Wrapping Process by Membrane

by Xinpei Meng and Xinlei Li

Nanomaterials 2018, 8(11), 899; https://doi.org/10.3390/nano8110899 - 02 Nov 2018

Cited by 14 | Viewed by 3409

Abstract

The wrapping of nanoparticles (NPs) by a membrane is a phenomenon of widespread and generic interest in biology, as well as in a variety of technological applications, such as drug delivery, clinical diagnostics, and biomedical imaging. However, the mechanisms of the interaction between [...] Read more.

The wrapping of nanoparticles (NPs) by a membrane is a phenomenon of widespread and generic interest in biology, as well as in a variety of technological applications, such as drug delivery, clinical diagnostics, and biomedical imaging. However, the mechanisms of the interaction between the membrane and NPs are not well understood yet. In this paper, we have presented an analytic thermodynamic model to investigate the wrapping process of NPs by a cell membrane. It is found that the bending energy of the deformed membrane increases nonlinearly with increasing wrapping degree, which leads to a free energy barrier for the wrapping. On the basis of analysis results, the wrapping of NPs can be divided into three types, i.e., impossible wrapping, barrier wrapping, and free wrapping. Furthermore, a phase diagram for the wrapping of NPs has been constructed, which clarifies the interrelated effects of the size and the ligand density of NPs. We hope that this work can provide some help in understanding the physical mechanism of the wrapping of NPs. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

► Show Figures

Figure 1

11 pages, 4115 KiB

Open AccessArticle

Au Nanoparticles as Template for Defect Formation in Memristive SrTiO₃ Thin Films

by Nicolas Raab, Dirk Oliver Schmidt, Hongchu Du, Maximilian Kruth, Ulrich Simon and Regina Dittmann

Nanomaterials 2018, 8(11), 869; https://doi.org/10.3390/nano8110869 - 23 Oct 2018

Cited by 8 | Viewed by 3004

Abstract

We investigated the possibility of tuning the local switching properties of memristive crystalline SrTiO

_{3}

thin films by inserting nanoscale defect nucleation centers. For that purpose, we employed chemically-synthesized Au nanoparticles deposited on 0.5 wt%-Nb-doped SrTiO

_{3}

single crystal substrates as a defect [...] Read more.

We investigated the possibility of tuning the local switching properties of memristive crystalline SrTiO

_{3}

thin films by inserting nanoscale defect nucleation centers. For that purpose, we employed chemically-synthesized Au nanoparticles deposited on 0.5 wt%-Nb-doped SrTiO

_{3}

single crystal substrates as a defect formation template for the subsequent growth of SrTiO

_{3}

. We studied in detail the resulting microstructure and the local conducting and switching properties of the SrTiO

_{3}

thin films. We revealed that the Au nanoparticles floated to the SrTiO

_{3}

surface during growth, leaving behind a distorted thin film region in their vicinity. By employing conductive-tip atomic force microscopy, these distorted SrTiO

_{3}

regions are identified as sites of preferential resistive switching. These findings can be attributed to the enhanced oxygen exchange reaction at the surface in these defective regions. Full article

(This article belongs to the Special Issue Nanoscale Surface Engineering)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Nanoscale Surface Engineering

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (10 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI