Search Results (18)

Herein, this study reports the development of a multifunctional conductive antibacterial cotton fabric through the utilization of the natural polyphenol-mediated silver mirror reaction. The experimental results demonstrate that polyphenols can effectively facilitate the deposition of silver nanoparticles (AgNPs), resulting in a uniform and durable hybrid nanocoating on the cotton fabric. The effects of polyphenol’s molecular weights on the coating structures and stabilities have been revealed via two distinct approaches: washing resistance and electrochemical testing systems. It has been concluded that lower-molecular-weight phenols induce a compact and dense coating structure, whereas polyphenols such as tannic acid exhibit relatively high stability, achieving an excellent conductivity of 0.2 S/cm and a good washing resistance of 67% over five cycles. The underlying mechanism has been further confirmed by the cyclic voltammetry measurements, suggesting that polyphenols play a significant role in stabilizing AgNPs and preventing their dissolution. Furthermore, the Ag-doped polyphenol-coated fabrics exhibit notable antibacterial properties. By coupling natural polyphenols with typical silver mirror reactions, this study not only offers a sustainable alternative to synthetic chemicals but also presents a promising method to endow cotton textiles with the dual properties of conductivity and antibacterial activity. Full article

The objective of this study was to evaluate the effectiveness of trimethylsilane (TMS) plasma nanocoatings in protecting silver nanowires (AgNWs) from degradation and thus to improve their stability. TMS plasma nanocoatings at various thicknesses were deposited onto AgNWs that were prepared on three different substrates, including glass, porous styrene-ethylene-butadiene-styrene (SEBS), and poly-L-lactic acid (PLLA). The experimental results showed that the application of TMS plasma nanocoatings to AgNWs induced little increase, up to ~25%, in their electrical resistance but effectively protected them from degradation. Over a two-month storage period in summer (20–22 °C, 55–70% RH), the resistance of the coated AgNWs on SEBS increased by only ~90%, compared to a substantial increase of ~700% for the uncoated AgNWs. On glass, the resistance of the coated AgNWs increased by ~30%, versus ~190% for the uncoated ones. When stored in a 37 °C phosphate-buffered saline (PBS) solution for 2 months, the resistance of the coated AgNWs on glass increased by ~130%, while the uncoated AgNWs saw a ~970% rise. Increasing the TMS plasma nanocoating thickness further improved the conductivity stability of the AgNWs. The nanocoatings also transformed the AgNWs’ surfaces from hydrophilic to hydrophobic without significantly affecting their optical transparency. These findings demonstrate the potential of TMS plasma nanocoatings in protecting AgNWs from environmental and aqueous degradation, preserving their electrical conductivity and suitability for use in transparent electrodes and wearable electronics. Full article

In this work, bilayer nanocoatings were designed and constructed on high-performance aromatic polysulfonamide (PSA) fibers for robust electric conduction and electromagnetic interference (EMI) shielding. More specifically, PSA fibers were first endowed with necessary electric conductivity via electroless nickel (Ni) or nickel alloy (Ni-P-B) plating. Afterward, silver electroplating was carried out to further improve the performance of the composite. The morphology, microstructure, environmental stability, mechanical properties, and EMI shielding performance of the proposed cladded fibers were thoroughly investigated to examine the effects of electrodeposition on both amorphous Ni-P-B and crystalline Ni substrates. The acquired results demonstrated that both PSA@Ni@Ag and PSA@Ni-P-B@Ag composite fibers had high environment stability, good tensile strength, low electric resistance, and outstanding EMI shielding efficiency. This indicates that they can have wide application prospects in aviation, aerospace, telecommunications, and military industries. Furthermore, the PSA@Ni-P-B@Ag fiber configuration seemed more reasonable because it exhibited smoother and denser silver surfaces as well as stronger interfacial binding, leading to lower resistance (185 mΩ cm⁻¹) and better shielding efficiency (82.48 dB in the X-band). Full article

We report on a comparative in vitro study of selective cytotoxicity against MCF7 tumor cells and normal VERO cells tested on silver-based nanocoatings synthesized by the matrix-assisted pulsed laser evaporation (MAPLE) technique. Silver nanoparticles (AgNPs) were loaded with five representative cytostatic drugs (i.e., doxorubicin, fludarabine, paclitaxel, gemcitabine, and carboplatin) and with five essential oils (EOs) (i.e., oregano, rosemary, ginger, basil, and thyme). The as-obtained coatings were characterized by X-ray diffraction, thermogravimetry coupled with differential scanning calorimetry, Fourier-transform IR spectroscopy, IR mapping, and scanning electron microscopy. A screening of the impact of the prepared nanocoatings on the MCF7 tumor and normal VERO cell lines was achieved by means of cell viability MTT and cytotoxicity LDH assays. While all nanocoatings loaded with antitumor drugs exhibited powerful cytotoxic activity against both the tumor and the normal cells, those embedded with AgNPs loaded with rosemary and thyme EOs showed remarkable and statistically significant selective cytotoxicity against the tested cancercells. The EO-loaded nanocoatings were tested for antimicrobial and antibiofilm activity against Staphylococcus aureus, Escherichia coli, and Candida albicans. For all studied pathogens, the cell viability, assessed by counting the colony-forming units after 2 and 24 h, was significantly decreased by all EO-based nanocoatings, while the best antibiofilm activity was evidenced by the nanocoatings containing ginger and thyme EOs. Full article

Surface coating has become an effective approach to improve the electrochemical performance of Ni-rich cathode materials. In this study, we investigated the nature of an Ag coating layer and its effect on electrochemical properties of the LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode material, which was synthesized using 3 mol.% of silver nanoparticles by a facile, cost-effective, scalable and convenient method. We conducted structural analyses using X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy, which revealed that the Ag nanoparticle coating did not affect the layered structure of NCM811. The Ag-coated sample had less cation mixing compared to the pristine NMC811, which could be attributed to the surface protection of Ag coating from air contamination. The Ag-coated NCM811 exhibited better kinetics than the pristine one, which is attributed to the higher electronic conductivity and better layered structure provided by the Ag nanoparticle coating. The Ag-coated NCM811 delivered a discharge capacity of 185 mAh·g⁻¹ at the first cycle and 120 mAh·g⁻¹ at the 100th cycle, respectively, which is better than the pristine NMC811. Full article

One of the recommendations for future textile development is the modification of textiles to produce materials for human performance (sports, medical, and protective). In the current work, modifying a polyester surface with silver nanoparticles improved antioxidant and antibacterial protection. For this purpose, ethylenediamine aminolysis was utilized as ligands to fabricate polyester textiles, trapping silver ions to further reduce silver nanoparticles (AgNPs). Dopamine (PDA) was used to provide antibacterial and antioxidant properties to the polyester textile by converting silver ions into AgNPs through its phenolic hydroxyl groups. Pristine polyester, polyester treated with ethylenediamine, and PDA-coated AgNP-loaded polyester ethylenediamine were characterized using SEM, EDX, FTIR, TGA, and tensile strength. The antibacterial properties against Staphylococcus aureus and Escherichia coli were examined through the broth test. PDA-AgNPs composite nanocoating exhibited improved tensile strength and antibacterial and antioxidant properties, demonstrating that polyester with a PDA-AgNPs overlay may be used for long-term biomedical textiles. Full article

Antibacterial properties of engineered materials are important in the transition to a circular economy and societal security, as they are central to many key industrial areas, such as health, food, and water treatment/reclaiming. Nanocoating and electrospinning are two versatile, simple, and low-cost technologies that can be combined into new advanced manufacturing approaches to achieve controlled production of innovative micro- and nano-structured non-woven membranes with antifouling and antibacterial properties. The present study investigates a rational approach to design and manufacture electrospun membranes of polysulfone (PSU) with mechanical properties optimized via combinatorial testing from factorial design of experiments (DOE) and endowed with antimicrobial silver (Ag) nanocoating. Despite the very low amount of Ag deposited as a conformal percolating nanocoating web on the polymer fibers, the antimicrobial resistance assessed against the Gram-negative bacteria E. coli proved to be extremely effective, almost completely inhibiting the microbial proliferation with respect to the reference uncoated PSU membrane. The results are relevant, for example, to improve antifouling behavior in ultrafiltration and reverse osmosis in water treatment. Full article

Nanoparticles are increasingly utilized as coating materials to improve the properties of polyester textiles. In this work, polyester textiles were successfully fabricated, with hydrazide groups serving as ligands for the entrapment of sliver ions and subsequent reduction to AgNPs. Polydopamine (PDA) was used in this work to impart antibacterial and antioxidant properties to the polyester textiles through its phenolic hydroxyl groups, which can convert silver ions into AgNPs. Moreover, glucose was used as a reducing agent to create AgNPs-loaded polyester hydrazide. ATR-FTIR, SEM, EDX, thermogravimetric analysis (TGA), and tensile strength were used to characterize the pristine polyester, the polyester hydrazide, the PDA-coated AgNP-loaded polyester hydrazide and the AgNP-loaded polyester hydrazide. A broth test was also used to investigate the textile’s antimicrobial activities against Escherichia coli and Staphylococcus aureus. Overall, the composite nanocoating with PDA-AgNPs demonstrated good tensile strength and antioxidant and antibacterial characteristics, implying the practicality of PDA-AgNPs coating polyester for biomedical textile applications. Full article

In diverse living organisms, bionanocoatings provide multiple functionalities, to the surfaces they cover. We have, previously, identified the molecular mechanisms of Turing-based self-assembly of insect corneal nanocoatings and developed forward-engineering approaches to construct multifunctional soft bionic nanocoatings, encompassing the Drosophila protein Retinin. Here, we expand the versatility of the bionic nanocoatings, by identifying and using diverse Retinin-like proteins and different methods of their metallization, using nickel, silver, and copper ions. Comparative assessment, of the resulting bactericidal, antiviral, and cytotoxic properties, identifies the best protocols, to construct safe and anti-infective metalized bionic nanocoatings. Upscaled application of these protocols, to various public surfaces, may represent a safe and economic approach to limit hazardous infections. Full article

The main goal of this study was to present a facile and inexpensive approach for the preparation of hybrid coatings by the deposition under ambient air conditions of silver-based silica materials on glass substrates, which can be used to improve solar cells’ performance. The silica materials containing silver nanoparticles (AgNPs) were synthesized by the hydrolytic condensation of tetraethylorthosilicate (TEOS), triethoxymethylsilane (MTES), and trimethoxyhexadecylsilane (HDTMES), under acidic conditions, at room temperature (25 ± 2 °C). The silver nitrate solution (AgNO₃, 0.1 wt. %) was used as a source of Ag⁺ ions. The final samples were investigated through Fourier Transform Infrared Spectroscopy–Attenuated Total Reflectance (FTIR–ATR), Transmission Electron Microscopy equipped with energy dispersive X–ray (TEM–EDX), UV–Vis spectroscopy, Atomic Force Microscopy (AFM), and Raman Spectroscopy (RS). The TEM images confirmed the formation of AgNPs and were found to be around 3 nm. It was observed that AgNPs were embedded in the silica matrix. EDX also confirmed the presence of the resulting AgNPs within the silica material. AFM images demonstrated that the morphology of the hybrid films’ surfaces can be changed as a function of sol–gel composition. RS analysis indicated that silanol groups were significantly present on the silver-based silica film surface. The UV–Vis spectra revealed that the hybrid coatings presented a reflectance of ~8%, at 550 nm. This study will enhance the value of nanocoating technology in optoelectronics, particularly in the development of nanostructures that improve the performance in thin-film solar cells. Full article

The development of environmentally friendly materials has been the focus of many research groups in recent years due to increased harmful effects of plastics on the environment. Bio-based materials are considered a key solution from a sustainable manufacturing perspective. The nano-coating of biopolymer blends with silver nanoparticles is the subject of challenging research projects in line with the EU Directive on environment protection and sustainable manufacturing. Coating biopolymers with silver nanoparticles provides an antimicrobial and antiviral active surface. In this work, we develop silver nanoparticle-coated biopolymer Arboblend V2 Nature pellets. The main goal is to obtain a new material with antibacterial action obtained from the blending of a biopolymer pellets with silver nanoparticles through physical vapor deposition. The study is divided in three steps. The first step represents the silver nano-coating of the Arboblend V2 Nature and the characterization of the coated/raw pellets. The second step involves the injection molding of the silver nano-coated pellets and the characterization of the samples obtained. The last step regards the press molding of the coated pellets in order to obtain thin films, as well as their characterization. The PVD-sputtering technique is used to coat the pellets with silver nanoparticles. This process is especially optimized for coating raw materials with high water content and small-size pellets. The mechanical properties, surface chemical composition and the thermal properties of the both virgin and silver nanoparticle-coated biopolymer pellets are measured and analyzed for mechanical and thermal resistance of the nano-coating layer. Differential scanning calorimetry, scanning electron microscopy, X-ray photoemission spectroscopy and nanoindentation mechanical testing is performed. The calorimetry test detects no significant alteration of the biopolymer produced from the PVD process and confirms the optimized PVD process for nano-coating of the Arboblend V2 Nature pellets with a viable application in nano-silver–biopolymer composite products. Full article

A previously developed fiber-based polyester (PES) stent, with mechanical properties comparable to commercial nitinol stents, was coated with metallic silver (Ag⁰) and silver oxides (Ag_xO) thin films through direct current (DC) magnetron sputtering. Ag⁰ and Ag_xO coatings provide antimicrobial properties to the stents to minimize the occurrence of coronary stent infections. Nevertheless, the stent interacts with the atmosphere and then with the biological fluids and may lead to the generation of silver species with diminished antimicrobial efficiency and/or prone to induce cytotoxicity. Therefore, stent coating nanostructures aged 3 months were thoroughly analyzed by X-ray photoelectron spectroscopy (XPS) and their antimicrobial and cytotoxicity properties were assessed. Aging led to the presence of silver carbonate and bicarbonate as well as chemisorbed oxygen species in Ag⁰ and Ag_xO coatings. Bactericidal efficacy was tested against an important nosocomial bacterium, particularly associated to indwelling devices: Staphylococcus epidermidis. Aged Ag⁰ and Ag_xO coating presented a Log reduction of 1 and 2 at their surface; respectively. However, aged stents were able to induce a Log reduction of 2 (Ag⁰) and 4 (Ag_xO) on the surrounding medium. Only aged Ag_xO stent was able to provide a mild reduction of the bacterium at its surface and a clear antimicrobial effect (Log reduction >3) within its vicinity. More importantly, both aged Ag⁰ and Ag_xO stents were shown to be compatible with fibroblasts cells indicating that they can be safely used as indwelling devices, despite the aging effect. Full article

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

Anti-infective surfaces are a modern strategy to address the issue of infection related to the clinical use of materials for implants and medical devices. Nanocoatings, with their high surface/mass ratio, lend themselves to being mono-layered on the material surfaces to release antibacterial molecules and prevent bacterial adhesion. Here, a “layer-by-layer” (LbL) approach to achieve a self-assembled monolayer (SAM) with high microbicidal effect on hydroxylated surfaces is presented, exploiting the reaction between a monolayer of thiolic functions on glass/quartz surfaces and a newly synthesized derivative of the well-known antibacterial compound silver sulfadiazine. Using several different techniques, it is demonstrated that a nano-monolayer of silver sulfadiazine is formed on the surfaces. The surface-functionalized materials showed efficient bactericidal effect against both Gram-positive and Gram-negative bacteria. Interestingly, bactericidal self-assembled nano-monolayers of silver sulfadiazine could be achieved on a large variety of materials by simply pre-depositing glass-like SiO₂ films on their surfaces. Full article

The increase of multidrug-resistant bacteria remains a global concern. Among the proposed strategies, the use of nanoparticles (NPs) alone or associated with orthopedic implants represents a promising solution. NPs are well-known for their antimicrobial effects, induced by their size, shape, charge, concentration and reactive oxygen species (ROS) generation. However, this non-specific cytotoxic potential is a powerful weapon effective against almost all microorganisms, but also against eukaryotic cells, raising concerns related to their safe use. Among the analyzed transition metals, silver is the most investigated element due to its antimicrobial properties per se or as NPs; however, its toxicity raises questions about its biosafety. Even though it has milder antimicrobial and cytotoxic activity, TiO₂ needs to be exposed to UV light to be activated, thus limiting its use conjugated to orthopedic devices. By contrast, gold has a good balance between antimicrobial activity as an NP and cytocompatibility because of its inability to generate ROS. Nevertheless, although the toxicity and persistence of NPs within filter organs are not well verified, nowadays, several basic research on NP development and potential uses as antimicrobial weapons is reported, overemphasizing NPs potentialities, but without any existing potential of translation in clinics. This analysis cautions readers with respect to regulation in advancing the development and use of NPs. Hopefully, future works in vivo and clinical trials will support and regulate the use of nano-coatings to guarantee safer use of this promising approach against antibiotic-resistant microorganisms. Full article