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[Display omitted] The size of silver nanoparticles (Ag NPs) and loading amount of Ag NPs onto their substrate/carrier are two key factors for their efficient applications. Herein, we present a facile method for in situ synthesizing ultrafine and highly loaded Ag NPs on the surface of tannin-coated catechol-formaldehyde resin (TA-CFR) nanospheres. TA-CFR nanospheres act as green and highly efficient reducing agents for converting silver ions (Ag+) into Ag NPs, and the size of resultant Ag NPs is only ∼ 7.5 nm, and the Ag NPs loading capacity of TA-CFR is as high as 61.5 wt%, both of which contribute to the very high specific surface area of Ag NPs. Consequently, the as-synthesized TA-CFR@Ag composites show high catalytic performance, and the catalytic rate for the reduction of 4-nitrophenol is almost 10 times higher than that of the control. Meanwhile, TA-CFR@Ag composites also possess high antibacterial activity, efficiently inhibiting the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Furthermore, tannin coating (thickness: ∼ 15 nm) minimizes the aggregation of Ag NPs, and enhances the reusability and stability of resultant Ag NPs, because of their high surface charges (the zeta potential is up to −65.5 ± 1.9 mV) and strong coordination capability with Ag NPs. This work provides a new frontier to develop multifunctional nanomaterials focusing on the green catalyst synthesis and environmental-remedy applications. [ABSTRACT FROM AUTHOR]

Silver nanoparticles with vanadium oxide nanowires were obtained using the vanadium oxide quantum dots as both reductants and stabilizers. It was loaded into electrospun dressing for efficient bacteria-infected wound healing as confirmed by both in vitro and in vivo tests. [Display omitted] Silver nanoparticles (AgNPs) have been widely recognised as effective antibacterial materials in textiles for enhancing wound healing. However, high loadings of AgNPs are toxic and expensive. Thus, it is ideal to prepare AgNPs in a favourable nanostructure for stable and effective conjugation with the textile carrier by selecting a reductant and stabiliser that contributes to the antibacterial effect. Here, silver nanoparticles/vanadium oxide nanowires (Ag/VO x NWs) were prepared via a one-step reduction strategy using vanadium oxide quantum dots (VO x QDs) as both the reductant and stabiliser. VO x QDs possess antibacterial properties, which aid in minimising the applied silver content while enhancing bactericidal performance. Silver can self-aggregate into nanoparticles as well as promote the formation of vanadium oxide nanowires (VO x NWs). Accordingly, the Ag/VO x NWs exhibited remarkable antibacterial effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The nanowire structure of the Ag/VO x NWs was favourable for effective loading into a sodium alginate (SA) gel fabric to form a wound dressing. The effective loading of Ag/VO x NWs on SA was conducive to the complete dispersion of the bacteriostatic agent and enhanced the antibacterial activity of AgNPs. The wound dressing efficiently suppressed the growth of wound bacteria and promoted wound healing in vivo. [ABSTRACT FROM AUTHOR]

[Display omitted] Burn wounds are susceptible to bacterial infections and are usually accompanied by a large amount of exudate, making the treatment of burn wounds a challenge in the clinic. Here, we developed a biodegradable cryogel with high water absorption and good antibacterial and antibiofilm activity based on gelatin (GT) and silver nanoparticles (Ag NPs) to promote burn wound healing. The porous GT/Ag cryogel had a swelling ratio of up to 4000%, effectively absorbing wound exudate and allowing for gas exchange. Moreover, the GT/Ag cryogel had an excellent killing effect on methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PA), which burn wounds are susceptible to, and can effectively remove mature biofilms. In the rat liver defect noncompressible hemorrhage model, GT/Ag cryogels with shape memory performance showed better hemostatic ability than commercial gelatin sponges. Most importantly, the GT/Ag cryogel was more effective than the TegadermTM dressing and GT cryogel in promoting wound contraction, collagen deposition, and angiogenesis and reducing inflammation in a PA-infected burn wound model. In addition, GT/Ag cryogels degraded in the body within 4 weeks, which alleviated the pain of peeling the dressing from the wound. Therefore, GT/Ag cryogels with outstanding antibacterial properties and effective absorption of wound exudates are excellent candidates for wound dressings to promote burn wound repair. [ABSTRACT FROM AUTHOR]

[Display omitted] A facile one-step method was developed to synthesize magnetically separable nanocomposite with a h-Fe 3 O 4 core and an Ag/polydopamine hybrid shell, of which exhibited excellent catalytic activity, antibacterial activity, and recyclability. A facile one-step method for synthesis of magnetic core–shell nanocomposite composed of h-Fe 3 O 4 (hollow Fe 3 O 4) core and stable PDA (polydopamine) shell with functional Ag NPs (silver nanoparticles) evenly distributed between them is developed. The h-Fe 3 O 4 @Ag/PDA nanocomposite showed excellent catalytic activity in the reaction for reducing azo dyes (methyl orange, methylene blue, and congo red), and the ratios of k values to the weight of h-Fe 3 O 4 @Ag/PDA were calculated to be 0.302, 0.0545, and 0.895 min−1 mg−1, respectively. Besides, the h-Fe 3 O 4 @Ag/PDA nanocomposite also exhibited good antibacterial activity in the experiment of culturing Bacillus subtilis , and the MIC (minimum inhibitory concentration) was as low as 12.5 μg/mL. Because the Ag NPs will not be leached in the solution under the protection of the PDA shell, the catalytic and antibacterial activities of h-Fe 3 O 4 @Ag/PDA nanocomposite could maintain more than 90% after five cycles. Intriguingly, this simple synthetic method can be extended to fabricate different multifunctional nanocomposites such as the spherical SiO 2 @Ag/PDA and rod-like Fe 2 O 3 @Ag/PDA. Overall, the facile fabrication process, the superior catalytic and antibacterial activity, and the excellent stability, endow the h-Fe 3 O 4 @Ag/PDA to be a promising nanocomposite. [ABSTRACT FROM AUTHOR]

AgNPs loaded quaternized lignin (QAL) composites (Ag@QAL) were synthesized in-situ with the assistance of the microwave radiation with enhanced antibacterial activity. Lignin has been considered as a green carrier with excellent biocompatibility for the biomedical applications in drug release, tissue engineering, etc. In this study, silver nanoparticles (AgNPs) incorporated quaternized lignin (QAL) composites (Ag@QAL) were synthesized in-situ with the assistance of the microwave radiation. The positive charged QAL, not only serves as reductive and stabilizing carriers, but also endows with electrostatic effect toward negatively charged Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), resulting in greatly enhanced antibacterial activity. It is worth mentioning that Ag@QAL exhibits the highest antibacterial activity, which causes 3.72 log 10 (>99.9%) and 5.29 log 10 (>99.999%) CFU/ml reduction against E. coli and S. aureus respectively after contacting for only 5 min. Furthermore, due to the strong interaction between Ag@QAL and Ag+/AgNPs, bacteria can be captured and co-precipitated by Ag@QAL fastly in 30 min with almost none silver ions detected in the supernatant, which prevents Ag+ leaking with extremely low toxicity to the biological environment. This concept of electrostatic capture effect induced antibacterial activity enhancement and environmentally benign features may provide new insights into the design of highly effective antibacterial agents in a sustainable manner. [ABSTRACT FROM AUTHOR]

Ultrasmall silver nanoclusters (Ag NCs) are one of the emerging and highly efficient antibacterial agents, owing to the unique features of sub-2 nm particle size and the high abundance of the active Ag+ species. However, practical applications of Ag NCs in biological environment are often hampered by silver oxidization, which results in particle aggregation and loss of antibacterial activity. In this study, for the first time, we develop a facile method to synthesize highly dispersed Ag NCs decorated mesoporous silica nanoparticles (Ag NC-MSNs) capable of long-term and efficient release of Ag+ ions. This novel Ag NC-MSNs nanocomposite was demonstrated as an effective antibacterial agent against both Gram-positive and Gram-negative pathogenic bacteria. Compared with the counterparts Ag NCs and silver nanoparticles decorated mesoporous silica nanoparticles (Ag NP-MSNs), Ag NC-MSNs exhibit 17-fold and 27-fold enhancement in antibacterial potency, respectively. The homogeneous distribution of ultrasmall Ag NCs in the mesoporous architecture of supporting MSNs matrix is crucial for the controlled release of Ag+ ions, leading to the superior broad-spectrum antimicrobial activity. Moreover, the cytotoxicity assay indicated that the effective antibacterial concentration of Ag NC-MSNs shows minimum toxicity on mammalian cells. This new Ag nanocomposite developed in this work is promising for practical applications against various microbial infections. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Staphylococcus aureus (S. aureus) is a leading cause of keratitis worldwide and a significant threat to healthy vision. Pathological manifestations of bacterial keratitis (BK) caused by S. aureus involve stromal opacity, edema and neovascularization of an inflamed cornea, requiring immediate medical attention. Thus, S. aureus -induced keratitis is a devastating ocular infection that can lead to blindness if effective and timely treatment is not initiated. In this study, we demonstrate gelatin-capped silver nanoparticles (G-Ag NPs) as anti-infective therapeutics for the treatment of S. aureus -induced keratitis. G-Ag NPs were prepared by simple mixing of silver nitrate, maltose and gelatin. The gelatin molecules are capped in situ on the Ag NPs (∼14 nm). Compared to uncapped Ag NPs, the G-Ag NPs possess superior stability and antibacterial activity against S. aureus. We further demonstrate that G-Ag NPs possess effective inhibition of the proliferation, migration and tube formation of human umbilical vein endothelial cells, as well as strong disturbance of the angiogenesis in chick chorioallantoic membrane and rabbit corneal neovascularization. Furthermore, intrastromal administration of highly biocompatible G-Ag NPs alleviates S. aureus -induced bacterial keratitis in rabbit eyes and bacterial infection-induced corneal neovascularization. Our results demonstrate G-Ag NPs as a promising dual functional (antimicrobial and antiangiogenic) nanotherapeutic for preclinical treatment of eye-related microbial infections. [ABSTRACT FROM AUTHOR]

Leather product with durable antibacterial property is of great interest both from industry and consumer’s point of view. To fabricate such functional leather, gallic acid modified silver nanoparticles (GA@AgNPs) were first in situ synthesized with a core–shell structure and an average size of 15.3 nm. Due to its hydrophilic gallic acid surface, the GA@AgNPs possessed excellent stability and dispersibility in wide pH range from 3 to 12 and also showed effective antibacterial activity with a minimum inhibitory concentration (MIC) of around 10 μg mL −1 . Then, such GA@AgNPs were used as retanning agent to be successfully filled into leather matrix during the leather manufacturing process. Moreover, taking the advantage of its high surface density of carboxyl groups, these GA@AgNPs could be further chemically cross-linked onto collagen fibers by chrome tanning agent. After retanning, the resultant leather was given a “AgNPs sponge” feature with high payload of silver nanoparticles against laundry, exhibiting high and durable antibacterial activity. [ABSTRACT FROM AUTHOR]

The synergistic wound healing and antibacterial activity of silver oxide nanoparticles embedded silk fibroin (Ag 2 O-SF) spuns is reported here. UV–Vis spectro photometric analysis of these spuns showed the surface plasmon resonance (SPR) confirming the formation of the silver oxide nanoparticles (Ag 2 O NPs) on the surface of the silk fibroin (SF). Scanning electron microscope (SEM) and Differential scanning calorimetry (DSC) also confirmed the presence of Ag 2 O NPs on surface of SF. X-ray diffraction (XRD) analysis revealed the crystalline nature of both SF and Ag 2 O-SF. Fourier transform infrared spectroscopy (FT-IR) results showed the different forms of silk (I and II) and their corresponding protein (amide I, II, III) confirmations. Biodegradation study revealed insignificant changes in the morphology of Ag 2 O-SF spuns even after 14 days of immersion in phosphate buffered saline (PBS). Ag 2 O-SF spuns showed excellent antibacterial activity against both pathogen ( S. aureus and M. tuberculosis ) and non-pathogen ( E. coli ) bacteria. More importantly, In vitro wound healing (scratch assay) assay revealed fast migration of the T3T fibroblast cells through the scratch area treated with extract of Ag 2 O-SF spuns and the area was completely covered within 24 h. Cytotoxicity assay confirmed the biocompatible nature of the Ag 2 O-SF spuns, thus suggesting an ideal material for wound healing and anti-bacterial applications. [ABSTRACT FROM AUTHOR]

Development of new functional coatings in the field of health care, as antibacterial applications, deals with a straight control of the diffusive properties that rules the releasing of the active component. In this work, the development of a silver-rich nanocomposite thin coating, loaded with organically modified clay nanoparticles, is presented. The synthesis process included an environment-friendly silanization process of clay nanoparticles (Laponite® S482) with (3-glycidoxypropyl)trimethoxysilane (GPTMS) and the further hydrolytic condensation with tetraethoxysilane (TEOS). Silanization process and the obtained coatings were analysed by Fourier transformed infrared spectroscopy, UV–visible spectroscopy, X-ray diffraction, thermogravimetric curves and scanning electron microscopy. The silanization process of clay nanoparticles with the organically reactive alkyl alkoxysilane, allowed to stabilize and exfoliate the clay nanosheets within a hybrid organic-inorganic sol-gel material. Ring opening of grafted epoxy groups carried to an increasing of the basal spacing, of intercalated clay nanosheets, from 1.3 to 1.8 nm. Moreover, incorporation of organically modified clay nanosheets introduced a significant stabilization on the development of silver nanoparticles inside the structure of the nanocomposite coating, retaining the silver inside the coating material and restricting the growing of silver nanoparticles on the surface of the coating. Antibacterial behaviour, against E . coli cultures, performed through agar diffusion tests, provided promising results that allow assuming that the studied nanocomposite coating serves as a reservoir of ionic silver, permitting the antibacterial effect. [ABSTRACT FROM AUTHOR]

The synthesis of Ag nanoparticles from Ag + has been investigated, with pectin acting both as reductant and coating. ∼100% Ag + to Ag(0) one-pot conversion was obtained, yielding p-AgNP, i.e. an aqueous solution of pectin-coated spherical Ag nanoparticles (d = 8.0 ± 2.6 nm), with a < 1 ppm concentration of free Ag + cation. Despite the low free Ag + concentration and low Ag + release with time, the nature of the coating allows p-AgNP to exert excellent antibacterial and antibiofilm actions, comparable to those of ionic silver, tested on E. coli (Gram−) and S. epidermidi s (Gram+) both on planctonic cells and on pre- and post-biofilm formation conditions. Moreover, p-AgNP were tested on fibroblasts: not only p-AgNP were found to be cytocompatible but also revealed capable of promoting fibroblasts proliferation and to be effective for wound healing on model cultures. The antibacterial activity and the wound healing ability of silver nanoparticles are two apparently irreconcilable properties, as the former usually requires a high sustained Ag + release while the latter requires low Ag + concentration. p-AgNP represents an excellent compromise between opposite requirements, candidating as an efficient medication for repairing wounds and/or to treat vulnerable surgical site tissues, including the pre-treatment of implants as an effective prophylaxis in implant surgery. [ABSTRACT FROM AUTHOR]

The achievement of uniform nanoparticles distribution in polymer matrix is still a major challenge in the design and fabrication of polymer nanocomposites with desired properties. In this paper we propose a novel approach for the preparation of homogeneous polystyrene/silver nanocomposites utilizing Nitroxide Mediated Radical Polymerization (NMRP). In the first step of the developed procedure, the polystyrene grafted silver nanoparticles (Ag@PS) with well-defined core-shell structure and exceptionally high grafting density (from 2 chains/nm 2 to 5.9 chains/nm 2 ) have been synthesized through late injection of nitroxide-coated silver nanoparticles (N-AgNPs) into a TEMPOL mediated styrene polymerization system. Afterwards, the synthesized Ag@PS have been used for the preparation of nanocomposites (PS/Ag@PS) by mixing them with narrow-dispersity polystyrenes and thermoforming at 140 °C. Due to the high flexibility of polymer chains attached to silver surface through nitroxide linker, free volume effect enables interpenetration of polystyrene molecules that provides excellent mutual miscibility of Ag@PS with polymer matrix. The synthesized nanohybrids (Ag@PS) and their nanocomposites (PS/Ag@PS) exhibit effective antibacterial activity with respect to pathogenic bacteria: Pseudomonas aeruginosa (Gram-negative representative) and Staphylococcus aureus (Gram-positive representative). [ABSTRACT FROM AUTHOR]

Development of eco-labeled and effectively antibacterial coatings for final leather products has been desiderated both by industry and by consumers. Herein, PEGylated chitosan modified silver nanoparticles (PEG-g-CS@AgNPs) were prepared and characterized by UV–vis spectroscopy, transmission electron microscopy and dynamic light scattering. The antimicrobial activity of such silver nanoparticles was investigated against Gram-negative Escherichia coli ( E. coli ) and Gram-positive Staphylococcus aureus ( S. aureus ), exhibiting much lower minimum inhibitory concentration (MIC) than chitosan or PEG-g-CS. Water-borne coating was formed by immobilizing the PEG-g-CS@AgNPs onto the leather surface through the electrostatic interaction between amino groups of chitosan and carboxyl groups of leather collagen. Scanning electron microscopy and water contact angle were employed to study the coating’s morphology and hydrophilicity, respectively. After coating, leather samples showed significantly high bactericidal efficiency with reusability after release of dead cells from the coating by simply water washing. The excellent antibacterial property of PEG-g-CS@AgNPs coating was ascribed to the combination of bacteria-resistance and bacteria-release by PEGylation, and dual bacteria-killing based on chitosan and Ag + release. [ABSTRACT FROM AUTHOR]

We describe herein a unique approach to synthesize zinc oxide-silica-silver (ZnO-SiO 2 -Ag) nanocomposite, in a simple, one-pot process. The typical process for ZnO synthesis by alkaline precipitation of zinc salts has been tweaked to replace alkali by alkaline sodium silicate. The free acid from zinc salts helps in the synthesis of silica nanoparticles, whereas the alkalinity of sodium silicate precipitates the zinc salts. Addition of silver ions into the reaction pot prior to addition of sodium silicate, and subsequent reduction by borohydride, gives additional functionality of metallic centres for catalytic applications. The synthesis strategy is based on our recent work typically involving acid-base type of cross-reactions and demonstrates a novel strategy to synthesize nanocomposites in a one-pot approach. Each component in the composite offers a unique feature. ZnO besides displaying mild catalytic and anti-bacterial behaviour is an excellent and a cheap 3-D support for heterogeneous catalysis. Silver nanoparticles enhance the catalytic & anti-bacterial properties of ZnO. Silica is an important part of the composite; which not only “glues” the two nanoparticles thereby stabilizing the nanocomposite, but also significantly enhances the surface area of the composite; which is an attractive feature of any catalyst composite. The nanocomposite is found to show excellent catalytic performance with very high turnover frequencies (TOFs) when studied for catalytic reduction of Rhodamine B (RhB) and 4-Nitrophenol (4-NP). Additionally, the composite has been tested for its anti-bacterial properties on three different bacterial strains i.e. E. coli , B. Cereus and Bacillus firmus . The mechanism for enhancement of catalytic performance has been probed by understanding the role of silica in offering accessibility to the catalyst via its porous high surface area network. The nanocomposite has been characterized by a host of different analytical techniques. The uniqueness of our product and process stems from the novel synthesis strategy, the choice and combination of the three moieties, increased surface area offered by silica, and cost effectiveness, thereby making our product and process commercially viable and sustainable for industrial applications. [ABSTRACT FROM AUTHOR]

Hypothesis Silver nanoparticles (AgNPs) have emerged as a powerful weapon against antibiotic resistant microorganisms. However, most conventional AgNPs syntheses require the use of hazardous chemicals and generate toxic organic waste. Hence, in recent year’s, plant derived and biomolecule based synthetics have has gained much attention. Cacao has been used for years for its medicinal benefits and contains a powerful reducing agent - oxalic acid. We hypothesized that, due to the presence of oxalic acid, cacao extract is capable of reducing silver nitrate (AgNO 3 ) to produce AgNPs. Experiments In this study, AgNPs were synthesized by using natural cacao extract as a reducing and stabilizing agent. The reaction temperature, time and reactant molarity were varied to optimize the synthesis yield. Findings UV–visible spectroscopy (UV–vis), dynamic light scattering (DLS) and transmission electron microscopy (TEM) characterization demonstrated that the synthesized AgNPs were spherical particles ranging in size from 35 to 42.5 nm. The synthesized AgNPs showed significant antibacterial activity against clinically relevant pathogens such as Escherichia coli , Pseudomonas aeruginosa , Staphylococcus aureus and Staphylococcus epidermidis . Importantly, these green AgNPs are not cytotoxic to human dermal fibroblasts (HDFs) at concentrations below 32 μg/ml. We conclude that cacao-based synthesis is a reproducible and sustainable method for the generation of stable antimicrobial silver nanoparticles with low cytotoxicity to human cells. The AgNPs synthesized in this work have promising properties for applications in the biomedical field. [ABSTRACT FROM AUTHOR]

Silver nanoparticle-decorated magnetic graphene oxide (MGO-Ag) was synthesized by doping silver and Fe 3 O 4 nanoparticles on the surface of GO, which was used as an antibacterial agent. MGO-Ag was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy dispersive X-ray (EDS), X-ray diffraction (XRD), Raman spectroscopy and magnetic property tests. It can be found that magnetic iron oxide nanoparticles and nano-Ag was well dispersed on graphene oxide; and MGO-Ag exhibited excellent antibacterial activity against Escherichia coli and Staphylococcus aureus . Several factors were investigated to study the antibacterial effect of MGO-Ag, such as temperature, time, pH and bacterial concentration. We also found that MGO-Ag maintained high inactivation rates after use six times and can be separated easily after antibacterial process. Moreover, the antibacterial mechanism is discussed and the synergistic effect of GO, Fe 3 O 4 nanoparticles and nano-Ag accounted for high inactivation of MGO-Ag. [ABSTRACT FROM AUTHOR]

Layer-by-layer (LbL) assembly is a versatile technique for the preparation of multilayered polymeric films. However, fabrication of LbL polymetic film on silk for the in situ growth of high-density silver nanoparticles (AgNPs) has not been realized. Herein poly(acrylic acid) (PAA)/poly(dimethyldiallylammonium chloride) (PDDA) multilayers are constructed on silk via the LbL approach, subsequently serving as a 3-dimensional matrix for in situ synthesis of AgNPs. After 8 rounds of LbL assembly, the silk is fully covered with a layer of polymeric film. AgNPs with good crystalline structures could be in-situ generated in the silk-coated multilayers and their amount could be tailored by adjusting the bilayer numbers. The as-prepared silk could effectively kill the existing bacteria and inhibit the bacterial growth, demonstrating the antimicrobial activity. Moreover, the release of Ag + from the modified silk can last for 120 h, rendering the modified silk sustainable antimicrobial activity. This work may provide a novel method to prepare AgNPs-functionalized antimicrobial silk for potential applications in textile industry. [ABSTRACT FROM AUTHOR]

In this paper, we chose rice husk as raw material and synthesized successfully porous carbon loaded with silver nanoparticles (RH-Ag) composites by simple and cost-effective method. The as-prepared RH-Ag composites have a BET-specific surface area of 1996 m 2 g −1 and result in strong capacity of bacteria adsorption. The result of antibacterial study indicated that the RH-Ag system displayed antibacterial activity that was two times better than pure Ag NPs. Our study demonstrates that the antibacterial activity of RH-Ag composites may be attributed to their strong adsorption ability with bacteria and result in the disorganization of the bacterial membrane ultrastructure. In addition, RH-Ag system was found to be durative slow-releasing of silver ions and biocompatible for human skin keratinocytes cells. In terms of these advantages, the RH-Ag composites have potential application in antibacterial infections and therapy. [ABSTRACT FROM AUTHOR]

Fabrication of silver nanoparticles (AgNPs)-modified silk for antibacterial application is one of the hottest topics in the textile material research. However, the utilization of a polymer as both 3-dimensional matrix and reductant for the in - situ synthesis of AgNPs on silk fibers has not been realized. In this work, a facile, efficient and green approach was developed to in - situ grow AgNPs on the polydopamine (PDA)-functionalized silk. AgNPs with the size of 30–90 nm were uniformly deposited on the silk fiber surface with the PDA coating layer as a reduction reagent. The AgNPs exhibit excellent face-centered cubic crystalline structures. The bacterial growth curve and inhibition zone assays clearly demonstrate the antibacterial properties of the functionalized silk. Both high Ag + release level and long-time release profile were observed for the as-prepared AgNPs–PDA-coated silk, indicating the high-density loading of AgNPs and the possible long-term antibacterial effects. This work may provide a new method for the preparation of AgNPs-functionalized silk with antibacterial activity for the clothing and textile industry. [ABSTRACT FROM AUTHOR]

As a class of green and designable solvents, ionic liquids (ILs) have been used extensively in inorganic synthesis. In those schemes, ILs were usually used as reaction media to replace water and organic solvents, and/or used as stabilizer and capping agents to act like an amphiphilic molecule or polymer. However, the unique properties of ILs were not fully utilized in the area of material preparation. In this study, a new protocol of “ILs–water interfacial synthesis” was developed and used for the preparation of Ag nanomaterials. Taking the advantage of tunable property of ILs–water interface, Ag nanomaterials with different morphology such as triangular nanoplates, polygonal nanoplates, and nanoparticles could be facilely obtained. Growth mechanism of the triangular Ag nanoplates has been investigated from structural characterization and molecular dynamics (MD) simulation. It was shown that growth of the nanoplates was under kinetic control mainly due to high viscosity and ionicity of the ILs. Furthermore, the antimicrobial performance of these Ag samples was tested to study the influence of shape of the Ag nanomaterials on the antimicrobial activity and the related antimicrobial mechanism. The results suggested that the efficient antimicrobial activity of the triangular Ag nanoplates was ascribed to their sharp corners and edges and large areas of active (1 1 1) crystal plane, which leads to the higher amount of leaching Ag + ion. [ABSTRACT FROM AUTHOR]

Highlights: [•] Cu and Ag Nps incorporated in situ in phenolic resin beads during polymerization. [•] Uniform and significant metal loading in the carbonized and activated beads. [•] Partial replacement of expensive Ag Nps with inexpensive Cu Nps. [•] Prepared materials applied as an effective antibacterial agent. [ABSTRACT FROM AUTHOR]

Highlights: [•] The additive anions were found to be of significant importance in determining the final products. [•] A new pathway was proposed for the formation of Ag0 that AgxAy act as the oxidant. [•] The formation mechanism was analyzed from the viewpoint of standard reduction potential. [•] The obtained AgNWs showed excellent and long-lasting bactericidal efficiency for both Staphylococcus aureus and Escherichia coli. [Copyright &y& Elsevier]

Abstract: Chitosan, associated with cellulose fibers, can be used for elaborating sponge-like structures (membranes, foams) for the binding of silver ions. The composite material has very promising antibacterial properties versus Pseudomonas aeruginosa (Gram−)≫ Escherichia coli (Gram−)> Staphylococcus hominis (Gram+)≫ Staphylococcus aureus (Gram+). The amount of silver required for bactericidal effect is quite low (below 0.1mg per disk, this means less than 6mgAgg−1) in antibiogram-type test but also for the treatment of water suspensions (in dynamic mode with water recycling). The presence of cellulose fibers improves the efficiency of metal binding, due to chitosan dispersion and enhancement of the availability and accessibility of amine groups. Silver nanoparticles (about 100nm) were observed by scanning electron microscopy. The photo-reduction (exposure to sun light or UV lamp) leaded to the partial aggregation of silver nanoparticles: metal ions that were released tended to aggregate at the surface of the material. [Copyright &y& Elsevier]

Abstract: Titanium is a corrosion-resistant and biocompatible material widely used in medical and dental implants. Titanium surfaces, however, are prone to bacterial colonization that could lead to infection, inflammation, and finally to implant failure. Silver nanoparticles (AgNPs) have demonstrated an excellent performance as biocides, and thus their integration to titanium surfaces is an attractive strategy to decrease the risk of implant failure. In this work a simple and efficient method is described to modify Ti/TiO2 surfaces with citrate-capped AgNPs. These nanoparticles spontaneously adsorb on Ti/TiO2, forming nanometer-sized aggregates consisting of individual AgNPs that homogeneously cover the surface. The modified AgNP–Ti/TiO2 surface exhibits a good resistance to colonization by Pseudomonas aeruginosa, a model system for biofilm formation. [ABSTRACT FROM AUTHOR]

Abstract: A two-step, easy synthetic strategy in solution has been optimized to prepare authentic monolayers of silver nanoparticles (NP) on MPTS-modified glass surfaces, that were investigated by AFM imaging and by quantitative silver determination techniques. NP in the monolayers remain firmly grafted (i.e. not released) when the surfaces are exposed to air, water or in the physiological conditions mimicked by phosphate saline buffer, as UV–Vis spectroscopy and AFM studies demonstrate. About 15% silver release as Ag+ ions has been found after 15days when the surfaces are exposed to water. The released silver cations are responsible of an efficient local microbicidal activity against Escherichia coli and Staphylococcus aureus bacterial strains. [ABSTRACT FROM AUTHOR]

Abstract: Silver nanoparticles are the most widely used antibacterial agents with a number of advantages. The higher degree of biocompatibility and long-term antibacterial activity can be achieved with hydrogel–silver nanoparticles. In this work, a simple and facile synthetic strategy is developed to control the size and shape of the silver nanoparticles within the hydrogel networks. The variation in cross-link density of the polymer network has been found not only to control the size of the nanoparticles between 1 and 10nm, but it also regulates shape of the nanostructures such as nanorods, nanocubes, etc. This approach takes the advantage of the existing free-space between the networks of hydrogels that not only acts as a template for nucleation of particles but also provides long term stability. Further, nanoparticles can be recovered at any time from the hydrogel networks. These hybrid nanocomposites release nanoparticles with time which can eventually promote for antibacterial application. It can be inferred from the study that fine tuning of the hydrogel synthetic parameters will enhance the possibilities of desired nano-product tailor made for particular applications. [Copyright &y& Elsevier]

Abstract: Photodegradation of Escherichia coli bacteria in presence of Ag–TiO2/Ag/a-TiO2 nanocomposite film with an effective storage of silver nanoparticles was investigated in the visible and the solar light irradiations. The nanocomposite film was synthesized by sol–gel deposition of 30nm Ag–TiO2 layer on ∼200nm anatase(a-)TiO2 film previously doped by silver nanoparticles. Both Ag/a-TiO2 and Ag–TiO2/Ag/a-TiO2 films were transparent with a SPR absorption band at 412nm. Depth profile X-ray photoelectron spectroscopy showed metallic silver nanoparticles with diameter of 30nm and fcc crystalline structure were self-accumulated on the film surface at depth of 5nm of the TiO2 layer and also at the interface of the Ag–TiO2 and a-TiO2 films (at depth of 30nm). Both OH− bounds and H2O contents were concentrated on the film surface and at the interface, as a profit in releasing more ionic (not metallic) silver nanoparticles. Antibacterial activity of the nanocomposite film against E. coli bacteria was 5.1 times stronger than activity of the a-TiO2, in dark. Photo-antibacterial activity of the nanocomposite film exposed by the solar light was measured 1.35 and 6.90 times better than activity of the Ag/a-TiO2 and a-TiO2, respectively. The main mechanism for silver ion releasing was inter-diffusion of water and silver nanoparticles through pores of the TiO2 layer. Durability of the nanocomposite film was at least 11 times higher than the Ag/a-TiO2 film. Therefore, the Ag–TiO2/Ag/a-TiO2 photocatalyst can be nominated as one of the effective and long-lasting antibacterial nanocomposite materials. [Copyright &y& Elsevier]