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Abstract The present research work describes a novel method for green synthesis of silver nanoparticles using purple heart plant leaves extract, which is recognized as frequently found in households as an ornamental plant. The aqueous methanolic extract of purple heart plant leaves was prepared and employed in the synthesis of stable silver nanoparticles via biological reduction method. The purple heart plant leaves extract-mediated synthesized silver nanoparticles were systematically optimized using Box-Behnken design considering the effect of various independent variables (factors) like concentration of AgNO 3 , temperature and volume of purple heart plant leaves extract solution on the responses like particle size and polydispersity index of synthesized silver nanoparticles were optimized. Mathematical modelling was performed using quadratic polynomial model and response surface analysis was done to understand the factor-response relationship. The synthesized silver nanoparticles at optimum condition were found to be of spherical in shape under TEM with particle size of 98 nm and polydispersity index of 0.15. Optimized silver nanoparticles were further characterized through UV-VIS spectrophotometry, FTIR spectroscopy and TEM imaging studies. Also, the silver nanoparticles were evaluated for antibacterial activity on E. coli and S. aureus. In a nutshell, the studies construed successful synthesis of silver nanoparticles along with thorough understanding of the associated factors influencing their quality characteristics and significantly improved antibacterial activity as beneficial effect. Graphical abstract Unlabelled Image Highlights • Silver nanoparticles were synthesized using purple heart plant leaves extract. • These synthesized silver nanoparticles were optimized by Box-Behnken design. • Particle size and polydispersity index were investigated as response variables. • Optimized silver nanoparticles showed 98 nm particle size and 0.15 polydispersity index. • Optimized silver nanoparticles showed antibacterial activity against E. coli and S. aureus. [ABSTRACT FROM AUTHOR]

Abstract Silver nanoparticles (AgNPs) are widely explored to enhance the antibacterial property of medical devices such as wound dressings. However, no consensus has been reached on the efficacy and safety of AgNP incorporation. This study aimed (1) to elucidate the effect of proteins and inorganic ions on the antibacterial properties, (2) to confirm the antibacterial efficacy in vivo, and (3) to evaluate the wound healing ability of AgNPs incorporation into chitosan-based membranes. Three membranes with different amount of AgNPs were prepared. The antibacterial properties and silver release profile were evaluated after interacting with phosphate buffered saline or with serum in vitro. The antibacterial efficacy and the wound healing ability were explored in vivo. The results indicated that the biological environment had strong influences on the silver release: the inorganic ions resulted in a slow release whereas the proteins formed a barrier to block the silver release. Consequently, high amount of AgNPs incorporation was necessary to achieve in vivo antibacterial effects. Moreover, the addition of AgNPs did not alter the wound healing rate and tissue response. We can conclude that the AgNP incorporation can enhance antibacterial efficacy of biomaterials without altering the wound healing ability of the chitosan-based membranes. Graphical abstract Unlabelled Image Highlights • The inorganic ions can slow down silver release from silver nanoparticles (AgNPs). • Proteins can form a barrier to block silver release from AgNPs loaded materials. • AgNPs incorporation can enhance the antibacterial efficacy of biomaterials. • A high amount of AgNPs is necessary to achieve in vivo antibacterial efficacy. • AgNPs incorporation did not alter the wound healing rate and tissue response. [ABSTRACT FROM AUTHOR]

Abstract A novel series of silver-doped mesoporous bioactive glass/poly(1,8-octanediol citrate) (AgMBG/POC) elastomeric biocomposite scaffolds were successfully constructed by a salt-leaching technique for the first time and the effect of inclusion of different AgMBG contents (5, 10, and 20 wt%) on physicochemical and biological properties of pure POC elastomer was evaluated. Results indicated that AgMBG particles were uniformly dispersed in the POC matrix and increasing the AgMBG concentration into POC matrix up to 20 wt% enhanced thermal behaviour, mechanical properties and water uptake ability of the composite scaffolds compared to those from POC. The 20%AgMBG/POC additionally showed higher degradation rate in Tris(hydroxymethyl)-aminomethane–HCl (Tris–HCl) compared with pure POC and lost about 26% of its initial weight after soaking for 28 days. The AgMBG phase incorporation also significantly endowed the resulting composite scaffolds with efficient antibacterial properties against Escherichia coli and Staphylococcus aureus bacteria while preserving their favorable biocompatibility with soft tissue cells (i.e. , human dermal fibroblast cells). Taken together, our results suggest that the synergistic effect of both AgMBG and POC make these newly designed AgMBG/POC composite scaffold an attractive candidate for soft tissue engineering applications. Graphical abstract A novel silver-containing mesoporous bioactive glass/poly(1,8-octanediol citrate) (AgMBG/POC) elastomeric biocomposite scaffolds has been synthesized by salt-leaching technique for tissue engineering application. Unlabelled Image Highlights • AgMBG/POC elastomeric biocomposite scaffolds were developed by salt-leaching technique. • The incorporation of AgMBG into POC matrix improved water absorption and degradability of biocomposite scaffolds. • The viability of E. coli and S. aureus was significantly reduced by biocomposites. • Elastomeric biocomposites were biocompatible toward human dermal fibroblast cells. [ABSTRACT FROM AUTHOR]

Abstract Infectious diarrhea caused by the food borne pathogen, Campylobacter jejuni , is a major threat to public health worldwide leads high incidence of child mortality each year. In the present study, hydrothermal synthesis of Silver-Graphene-TiO 2 nanocomposites along with TiO 2 , TiO 2 -Graphene and TiO 2 -silver nanocomposites was done and the samples were characterized using X-ray diffraction (XRD), tunneling electron microscopy (TEM) and UV–Vis Spectroscopy. Effect of silver and graphene addition on the broad spectrum antibacterial ability of TiO 2 was studied under visible light. Moreover, the effects on bacterial survival, membrane integrity, cellular motiltiy and biofilm formation of C. jejuni were also evaluated. A synergetic effect of silver and graphene on Silver-Graphene-TiO 2 nanocomposites was observed as indicated by its increased visible light sensitivity and enhanced antibacterial activity under visible light compared to its parent derivatives. Silver-Graphene-TiO 2 composites effectively reduced growth and caused leakage of protein and DNA from C. jejuni cell. Atomic Force Microscopy was used to confirm bacterial cell damage. Besides, it also reduced motillity, hydrophobicity and autoaggregation of C. jejuni and showed excellent inhibition of biofilm formation. Furthermore, no significant cytotoxicity of synthesized nanoparticles was observed in human cell lines. We propose that Silver-Graphene-TiO 2 composites can be used as effective antimicrobial agents to control the spread of C. jejuni by preventing both bacterial growth and biofilm formation. Highlights • Ag/Tio2-graphene nanocomposite was successfully prepared by hydrothermal method. • Ag/Tio2-graphene nanocomposite exhibited broad spectrum antibacterial activity. • The growth and motility of C. jejuni was reduced by the synthesized nanocomposite. • The nanocomposite decreased the hydrophobicity and auto aggregation ability of C. jejuni. • The nanocomposite showed excellent antibiofilm activity against C. jejuni. [ABSTRACT FROM AUTHOR]

Abstract Surface modification of Fe 3 O 4 nanoparticle with thiol groups was used for the immobilization of silver nano-particles to produce Fe 3 O 4 /SiO 2 -Pr-S-Ag NPs. The prepared catalyst was characterized by Inductively coupled plasma (ICP), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectrum (EDS), vibrating sample magnetometer (VSM) and Fourier transform infrared (FTIR) analysis. In this fabrication, thio-groups played an important role as a capping and stabilizing agent for Ag nanoparticles. Fe 3 O 4 /SiO 2 -Pr-S-Ag NPs show high catalytic activity as recyclable nanocatalyst toward degradation of 4-nitrophenol (4-NP), rhodamine B (RhB), and Methylene blue (MB) in the presence of NaBH 4 in water at room temperature. With the help of UV–Vis spectroscopy, catalysis reactions were examined. Furthermore, these reactions followed the pseudo-first order rate equation. Graphical abstract Unlabelled Image Highlights • Surface modification of Fe 3 O 4 nanoparticle with thiol groups were achieved. • Thio-groups played an important role as stabilizing agent for Ag nanoparticles. • Fe 3 O 4 /SiO 2 -Pr-S-Ag NPs show high catalytic activity for degradation of organic dyes. • The nanocatalyst can be magnetically recycled and reused. [ABSTRACT FROM AUTHOR]

Abstract A facile one step green synthesis of silver (AgNP), gold (AuNP) and platinum (PtNP) nanoparticles has been attempted using the rind extract of the fruit of Garcinia mangostana L. The rind of the fruit is enriched with wide varieties of natural resources which could be conveniently exploited as alternative for synthesis of nanoparticles eliminating the need for hazardous chemical methods. The formation of gold nanoparticles occurred at room temperature within a few seconds while the formation of silver and platinum nanoparticles was obtained after heating the solution for 20 min at 80 °C. Parameters such as contact time, temperature and pH were optimized to obtain the precise nanoparticles. The green synthesized nanoparticles were characterized using several state-of-the-art techniques like UV–Vis spectroscopic, FT-IR, HR-SEM and HR-TEM, XRD analyses and zeta potential measurements. Attempt has also been made to evaluate the antibacterial activity of the metal nanoparticles before and after combining with commercially used antibiotics as well as free antibiotics against human pathogenic bacteria. The bare silver nanoparticles (AgNP) showed relatively higher antibacterial activity than AuNP and PtNP and this activity was found to be more pronounced against gram negative bacteria than gram positive ones. Interestingly, all the three metal nanoparticles combined with antibiotics showed enhanced antibacterial activity against the pathogenic bacteria which suggested synergism between the nanoparticles and antibiotics. The high point of the present investigation has been that the Bacillus sp. which is highly resistant to streptomycin becomes highly susceptible to the same antibiotic when combined with gold nanoparticles. This particular observation opens up windows for the treatment of antibiotic resistant bacteria after combining with different nanoparticles under clinical set up. Highlights • The rinds of G. mangostana are discarded as wastes after fruit consumption can be effectively used for synthesizing nanoparticles. • The reduction potential of aqueous rind extract of G. mangostana was relatively higher with HAuCl 4 than AgNO 3 and H 2 PtCl 6. • The gold nanoparticles were stable for over 6 months at 4⁰C and this property can be exploited for fabrication of drugs. • Conjugation of antibiotics with nanoparticles has drastically enhanced the antibacterial activity when compared to bare nanoparticles. • Bacillus sp. which is inherently resistant to free streptomycin antibiotic, has become highly susceptible to nanoparticles conjugated with streptomycin. • These kinds of study can be extended to other drug resistant bacteria and with different antibiotic and nanoparticles combinations. [ABSTRACT FROM AUTHOR]

Abstract The biofilm accumulation over the composite resin restorations can contribute to the formation of secondary caries. In this way, antibacterial restorative composite resins are highly desired. Then, the purpose of this study was to modify a composite resins using Ag doped ZnO nanoparticles (NPs), evaluate the antibacterial and mechanical properties of the modified composite resin. The ZnO/AgNPs were synthesized by two different routes, polymeric precursor and coprecipitation methods, and characterized by thermal decomposition, X-ray diffraction, specific surface area by N 2 desorption/desorption and scanning electron microscopy (SEM). Antibacterial activity of composite resin specimens (4 mm in height and 2 mm in diameter; n = 15) modified by ZnO/Ag nanoparticles was performed against 7-days Streptococcus mutans biofilm. Colony forming units (CFU/mL) were used to evaluate the bacterial activity. Additionally, the morphology and the bacteria adherence area were analyzed by SEM images. Cylindrical specimens (6 mm in height and 4 mm in diameter; n = 20) of the composite resin containing ZnO/Ag NPs were prepared to perform compressive strength in a universal mechanical test machine, and the surface of fractured specimens was analyzed by EDX element mapping to verify NPs homogeneity. The normal distribution was confirmed and the two-way analysis of variance (ANOVA) and Tukey's test for pair comparison were performed. The nanospheres of ZnO/Ag lead to a better biofilm inhibition, than nanoplates. No difference on compressive strength was found for the composite resin modified by ZnO/Ag nanoplates. Based on these results, this material could be a good option as a new restorative material. Highlights • ZnO micro and nanoparticles with antimicrobial properties were satisfactorily synthetized by the different routes. • The composite resin containing ZnO particles significantly inhibit the S. mutans biofilm. • The compressive strength of the composite resin containing Ag/ZnO nanoplates did not drastically changed. [ABSTRACT FROM AUTHOR]

For first time, we designed an environment friendly technique novel hybrid magnetic nanocomposite with the potency of both reducing and stabilizing agent for immobilization of metal nanoparticles. Stachys lavandulifolia extract having a lot of carbonyl and phenolic hydroxyl functional groups can be applied in the Fe 3 O 4 NPs modification. Furthermore, in aqueous solution, the complexation feasibility of polyphenols with silver ions can enhance the capacity and surface properties of the Fe 3 O 4 @ S. lavandulifolia NPs for sorbent and in situ reduction of silver ions. So, as both the stabilizing and reducing agent, the novel magnetic nano-sorbent (Fe 3 O 4 @ S. lavandulifolia NPs) has potential ability for silver nano particles immobilization to create a novel magnetic silver nanocatalyst. So that, no additional reductants, toxic reagents and intricate instruments are needed to prepare the catalyst. The morphology, structure, and physicochemical properties were elucidated by several analytical methods like, field emission scanning electron microscope (FESEM), high resolution transmission electron microscopy (HRTEM) images, energy-dispersive X-ray spectroscopy (EDS), vibrating sample magnetometer (VSM), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), FT-IR spectroscopy, and inductively coupled plasma (ICP). As recyclable nanocatalyst, Fe 3 O 4 @ S. lavandulifolia /Ag indicated high catalytic activity for 4-nitrophenol (4-NP) reduction at ambient temperature. Ultimately, the Fe 3 O 4 @ S. lavandulifolia /Ag antibacterial properties was examined against two bacteria ( Staphylococcus aureus (Staph. aureus) and Escherichia coli ( E. coli )) and indicated its antibacterial activities against gram negative ( E. coli ) bacteria and gram positive ( Staph. aureus ). [ABSTRACT FROM AUTHOR]

A new method was developed for the characterization and detection of ketoconazole using surface enhanced Raman spectroscopy (SERS) by designing substrates and performing the bands' assignments. Thus, spherical silver nanoparticles (Ag-NPs) were synthesized by a reduction method and designed as substrates for SERS application. The Ag-NPs were characterized using a scanning electron microscope, Fourier transformed infrared spectroscopy and a high-resolution transmission electron microscope. TEM results indicated that the average size of the Ag-NPs was 15 nm. The UV spectrum showed a maximum absorbance of Ag-NPs at about 400 nm. When Ag-NPs were used as substrates in SERS, the Raman spectra of KCZ showed a significant enhancement of the Raman bands. An important finding is a linear relationship between the logarithmical scale of KCZ concentration and the intensity of the SERS bands, for example at 1050 cm − 1 of KCZ, which is due to the C N vibration. This was optimized and utilized to develop a calibration curve, which was then used for the detection of the KCZ in real pharmaceutical samples. The method has the advantages of a wide dynamic range with a high coefficient of determination and detection limit calculated based on the signal-to-noise ratio of 3, was 2.6 × 10 − 10 M and the limit of quantification was 7.8 × 10 − 10 M. The potential applications that take advantage of the high SERS sensitivity of this method are discussed for practical KCZ analysis where were quantified with this method. [ABSTRACT FROM AUTHOR]

Biomedical titanium (Ti) implants with good anti-infective, osteogenic, and angiogenic properties are in great demand. SrTiO 3 nanotubes (NTs) are embedded with silver oxide (Ag 2 O) nanoparticles (NPs) (denoted as NT-Sr-Ag) by a hydrothermal treatment of TiO 2 NTs containing Ag 2 O NPs (denoted as NT-Ag) in a Sr(OH) 2 solution. The morphology, composition, microstructure, ion release phenomenon, as well as antibacterial, osteogenic, and angiogenic activities are investigated in details. During the hydrothermal treatment, the amorphous TiO 2 in the NTs morphs into cubic SrTiO 3 gradually and the ordered nanotubular architecture is preserved. Some Ag 2 O NPs are incorporated into the structure although some of them dissolve in the solution. Long-term bacterial resistance against Staphylococcus aureus is observed as a result of the prolonged and controllable Ag + release. NT-Sr-Ag can also release Sr 2 + similarly to stimulate osteoblasts to secrete the vascular endothelial growth factor (VEGF). Both the released Sr 2 + and secreted VEGF upregulate the alkaline phosphatase (ALP) activity and extracellular matrix mineralization of osteoblasts. Furthermore, better angiogenic activity is observed when endothelial cells are cultured in NT-Sr-Ag conditioned media when compared with that in NT-Ag conditioned media, which is believed to be ascribed to the positive regulation of VEGF secretion of Sr 2 + . NT-2Sr-Ag and NT-3Sr-Ag (Hydrothermal treatment for 2 and 3 h, respectively) exhibit excellent antibacterial, osteogenic, and angiogenic activities and are promising in biomedical implants. [ABSTRACT FROM AUTHOR]

In recent years, there has been growing interest in glasses showing antimicrobial property. Their high chemical stability, hardness, transparency and long lasting antimicrobial activity makes them favorably usable for many different applications either in bulk or powdered form. The present study deals with imparting antimicrobial property to the powdered soda lime glasses by applying ion exchange treatment. Ag + –Na + exchange was realized using AgNO 3 –NaNO 3 ionic medium at different concentrations for varying ion exchange temperature and ion exchange time. Glasses were evaluated in terms of the amount of incorporated silver into the glass, possible phase formations after the ion exchange treatment, the concentration of released silver ions into aqueous environment and their antimicrobial kullanılabactivity. Silver incorporation into the glass was efficiently realized within the studied experimental conditions. Silver release behavior of the glass samples were examined in aqueous environment; the results showed that the controlled level of release was obtained. Antimicrobial susceptibility test using liquid broth medium were performed to evaluate the antimicrobial efficacy of the glasses against Escherichia coli , Staphylococcus aureus and Candida albicans cells. Glasses showed strong antimicrobial activity against the selected microorganisms within the 24 hours contact time. [ABSTRACT FROM AUTHOR]

A fast, easy and novel method for preparing biodegradable polymer films with silver nanoparticles was investigated to endow the material with excellent biocompatibility and antibacterial property. Silver nanoparticles (Ag NPs) were immobilized on the surface of polylactic acid (PLA) film by gamma radiation induced grafting of N-vinyl pyrrolidone (NVP). In this method, poly (N-vinyl pyrrolidone) (PVP) was produced and grafted onto the surface of PLA film by gamma radiation polymerization of NVP. PVP acted as both a bridge to connect the Ag NPs with the PLA film, and a stabilizer to protect the Ag NPs from agglomeration. The effect of various reaction parameters, including NVP/Ag mole ratio and radiation dose, on the fabrication of PLA-g-NVP/Ag film was demonstrated. Moreover, the interaction between PVP and Ag NPs was studied by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, that revealed the Ag NPs coordinated through the oxygen atom on the carbonyl group of PVP at 15 kGy radiation dose, but through the nitrogen atom and the oxygen atom of the amide group of PVP at 1 kGy dose. [ABSTRACT FROM AUTHOR]

Discouraging bacterial colonization of ocular biomaterials and implants is a significant challenge in ophthalmology as infections often lead to the need for secondary surgery, with associated risks and additional stress to patients. In this work we demonstrate for the first time the feasibility of an innovative antibacterial ocular prosthesis produced by depositing a silver nanocluster/silica composite layer on the poly(methyl methacrylate) implant surface via radio-frequency sputtering. Tape test performed according to relevant ASTM standard provided a preliminary evidence of the mechanical stability and good adhesion of the coating to the substrate (absence of macroscopic damage after tape removal). Coating integrity was maintained after prolonged soaking in aqueous medium (1 month). The antibacterial effect of the coating, associated to silver ion release upon contact with aqueous fluid, was confirmed by the in vitro formation of a 5-mm inhibition halo test against Staphylococcus aureus that is one of the most common bacteria involved in ocular infections. The approach proposed in the present study for facing implant-related ocular infections can have a significant impact in the field of ophthalmic biomaterials, suggesting a valuable alternative to the administration of antibiotics that may become ineffective due to bacterial resistance. [ABSTRACT FROM AUTHOR]

We report a simple route to prepare silver nanoparticle (Ag NP) loaded amine functionalized poly-oligomeric (ethylene glycol) methyl ether methacrylate block poly-glycidyl methacrylate (POEGMA- b -PGMA) vesicles as an effective antibacterial agent. Self-assemblies of POEGMA- b -PGMA were prepared from reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization mediated by a POEGMA macro-chain transfer agent (macro-CTA) in ethanol. Amine-functionalized self-assemblies were applied for Ag NP loading by using amine and hydroxyl groups as both the coordination agent and reductant under hydrothermal condition in high-pressure steam sterilization. 12.7 wt.% content of fine Ag NP well-dispersed in vesicles showed excellent antibacterial activities with the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) below 5.0 and 10.0 mg/L against Escherichia coli and 2.5 and 80 mg/L against Staphylococcus aureus respectively. [ABSTRACT FROM AUTHOR]

In the current investigation we report the biosynthesis potentials of bark extracts of Ficus benghalensis and Azadirachta indica for production of silver nanoparticle without use of any external reducing or capping agent. The appearance of dark brown color indicated the complete nanoparticle synthesis which was further validated by absorbance peak by UV–vis spectroscopy. The morphology of the synthesized particles was characterized by Field emission- scanning electron microscopy (Fe-SEM) and atomic force microscopy (AFM). The X-ray diffraction (XRD) patterns clearly illustrated the crystalline phase of the synthesized nanoparticles. ATR-Fourier Transform Infrared (ATR-FTIR) spectroscopy was performed to identify the role of various functional groups in the nanoparticle synthesis. The synthesized nanoparticles showed promising antimicrobial activity against Gram negative ( Escherichia coli , Pseudomonas aeruginosa and Vibrio cholerae ) and Gram positive ( Bacillus subtilis ) bacteria. The synthesized nano Ag also showed antiproliferative activity against MG-63 osteosarcoma cell line in a dose dependent manner. Thus, these synthesized Ag nanoparticles can be used as a broad spectrum therapeutic agent against osteosarcoma and microorganisms. [ABSTRACT FROM AUTHOR]

Infection in primary total joint prostheses is attracting considerable attention. In this study, silver (Ag) was incorporated into hydroxyapatite (HA) using a hydrothermal method in order to improve its antimicrobial properties. Strontium (Sr) was added as a second binary element to improve the biocompatibility. The substituted HA samples were fixed on titanium (Ti) substrates by dopamine-assisted immobilization in order to evaluate their antibacterial and biological properties. The results showed that Ag and Sr were successfully incorporated into HA without affecting their crystallinity. Further, the antibacterial tests showed that all the Ag-substituted samples had good anti-bacterial properties against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). Despite their good antibacterial ability, the Ag-substituted samples showed evidence of cytotoxicity on MG63 cells, characterized by low cell density and poor spreadability. The addition of Sr to the Ag-substituted samples considerably reduced the cytotoxicity of Ag. Although the viability of the cells grown on the surfaces of co-substituted HA was not as high as that of the cells grown on the HA surfaces, it is believed that excellent antibacterial properties and good biological activity can be achieved by balancing the dosage of Sr and Ag. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) have attracted intensive research interest and have been recently incorporated in polymers, medical devices, hydrogels and burn dressings to control the proliferation of microorganisms. In this study a novel silver antibacterial coating was deposited for the first time on hydrogel fibers through an in-situ photo-chemical reaction. Hydrogel blends obtained by mixing different percentages of silver-treated and untreated fibers were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Four different fluids, such as phosphate buffered saline (PBS), simulated body fluid (SBF), chemical simulated wound fluid (cSWF), and deionized water (DI water), were used for evaluating the swelling properties. The results obtained confirmed that the presence of silver did not affect the properties of the hydrogel. Moreover, the results obtained through inductively coupled plasma mass spectrometry (ICP-MS) demonstrated very low silver release values, thus indicating the perfect adhesion of the silver coating to the substrate. Good antibacterial capabilities were demonstrated by any hydrogel blend on Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) through agar diffusion tests and optical density readings. [ABSTRACT FROM AUTHOR]

Infections are frequent and very undesired occurrences after orthopedic procedures; furthermore, the growing concern caused by the rise in antibiotic resistance is progressively dwindling the efficacy of such drugs. Artificial bone graft materials could solve some of the problems associated with the gold standard use of natural bone graft such as limited bone material, pain at the donor site and rejections if donor tissue is used. We have previously described new acrylate base nanocomposite hydrogels as bone graft materials. In the present paper, we describe the integration of silver nanoparticles in the polymeric mineralized biomaterial to provide non-antibiotic antibacterial activity against Staphylococcus epidermidis and Methicillin-resistant Staphylococcus aureus . Two different crosslinking degrees were tested and the silver nanoparticles were integrated into the composite matrix by means of three different methods: entrapment in the polymeric hydrogel before the mineralization; diffusion during the process of calcium phosphate crystallization and adsorption post-mineralization. The latter being generally the most effective method of encapsulation; however, the adsorption of silver nanoparticles inside the pores of the biomaterial led to a decreasing antibacterial activity for adsorption time longer than 2 days. [ABSTRACT FROM AUTHOR]

Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver–imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with l -cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli . It was found that PMMA films doped with Ag + had greater activity than those doped with nanoparticles and silver–imidazole polymeric complexes. However, the antimicrobial efficiency of Ag + doped films was only short-term. Contrary, the antimicrobial activity of silver–imidazole/PMMA films increased in time of sample soaking. [ABSTRACT FROM AUTHOR]

A simple, environmentally friendly and cost-effective method has been developed to prepare a range of aqueous silver colloidal solutions, using ascorbic acid as a reducing agent, water-soluble starch as a combined crystallising, stabilising and solubilising agent, and water as the solvent. The diameter of silver nanoplatelets increases with higher concentrations of AgNO 3 and starch. The silver nanoparticles are also more uniform in shape the greater the diameter of the nanoparticles. Colloidal solutions with a very high concentration of large, flat, hexagonal silver nanoplatelets (~ 230 nm in breadth) have been used to deposit and fix an antibacterial coating of these large starch-stabilised silver nanoplates on commercial cotton fibres, using a simple dip-coating process using water as the solvent, in order to study the dependence of the antibacterial properties of these nanoplatelets on their size. [ABSTRACT FROM AUTHOR]

Abstract: Hydroxyapatite (HA) coated implant is more susceptible to bacterial infection as the micro-structure surface which is beneficial for osseointegration, could also become a reservoir for bacterial colonisation. The aim of this study was to introduce the antibacterial effect of silver (Ag) to the biomineralised HA by utilising a polydopamine film as an intermediate layer for Ag and HA immobilisation. Sufficient catechol groups in polydopamine were required to bind chemically stainless steel 316L, Ag and HA elements. Different amounts of Ag nanoparticles were metallised on the polydopamine grafted stainless steel by varying the immersion time in silver nitrate solution from 12 to 24h. Another polydopamine layer was then formed on the metallised film, followed by surface biomineralisation in 1.5 Simulated Body Fluid (SBF) solution for 3days. Several characterisation techniques including X-Ray Photoelectron Spectroscopy, Atomic Force Microscopy, Scanning Electron Microscopy and Contact Angle showed that Ag nanoparticles and HA agglomerations were successfully immobilised on the polydopamine film through an element reduction process. The Ag metallisation at 24h has killed the viable bacteria with 97.88% of bactericidal ratio. The Ag was ionised up to 7days which is crucial to prevent bacterial infection during the first stage of implant restoration. The aged functionalised films were considered stable due to less alteration of its chemical composition, surface roughness and wettability properties. The ability of the functionalised film to coat complex and micro scale metal make it suitable for dental and orthopaedic implants application. [Copyright &y& Elsevier]

Abstract: A silver containing coating used in the human body, e.g., on an implant should be both effectively antimicrobial and non-cytotoxic to human cells. It is generally believed that the biologic effect originates from silver ions released from the coating. Nanocomposites with well controlled Ag filling factor were prepared by co-sputtering, and the silver surface concentration and the silver release were determined by XPS and ICP-MS, respectively. Here we show that only a small therapeutic window exists for dissolved silver but the therapeutic window is largely increased at the surface. While the toxicity observed for mammalian cells in contact with the bioactive Ag/TiO2 nanocomposite surface and for silver ions in solution is rather similar the antimicrobial activity is drastically enhanced at the surface. A model is proposed to explain the strong increase of the antimicrobial activity at the surface. The present results not only question well-established tests for antimicrobial activity but they are also important for the design of antimicrobial coatings, e.g., for biomedical devices. [Copyright &y& Elsevier]

Abstract: Uniform silver nanoparticles and silver/polystyrene core-shell nanoparticles were successfully synthesized in a room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]·BF4). [BMIM]·BF4 plays a protective role to prevent the nanoparticles from aggregation during the preparation process. Transmission electron micrographs confirm that both silver nanoparticles and core-shell nanoparticles are regular spheres with the sizes in the range of 5–15 nm and 15–25 nm, respectively. The X-ray diffraction analysis reveals the face-centered cubic geometry of silver nanoparticles. The as-prepared nanoparticles were also characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, UV–vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. In addition, antimicrobial activities against E. coli and S. aureus were studied and the results show that both silver nanoparticles and core-shell nanoparticles possess excellent antimicrobial activities. The antimicrobial mechanism of the as-prepared nanoparticles was discussed. [Copyright &y& Elsevier]

Hydroxyapatite is widely utilized for different biomedical applications because of its outstanding biocompatibility and bioactivity. Cuttlefish bones, which are available aplenty, are both inexpensive and eco-friendly sources for calcium carbonate. In the present study, cuttlefish bones-derived HAp nanorods have been utilized to fabricate HAp nanocomposites incorporating 1, 3 and 5 wt% each of GO, MWCNTs, GONRs and Ag NPs. Characterization using such techniques as XRD, FTIR, HRSEM and EDS was performed to analyze the physicochemical properties of nanocomposites, and MTT assay, hemolysis, bioactivity and drug release to evaluate the biological properties. The XRD and HRSEM results reveal that crystallite and particle size increase with increasing wt% of carbon nanomaterials and Ag NPs. However, the addition of nanomaterials did not modify the shape of HAp. The MTT assay and hemolysis results suggest GONRs possess better biocompatibility than GO and CNTs due to their smooth edge structure. While adding carbon materials up to 3 wt% caused an increase in the hardness, adding up to 5 wt% of them caused a decrease in the hardness due to the agglomeration of the particles. Biocompatibility and Vicker's hardness studies show that adding carbon nanomaterials up to 3 wt% caused significant improvement in biocompatibility and mechanical properties. Antibacterial activity test was performed to analyze the ability to preclude the formation of biofilms. The results showed better activity for silver-incorporated nanocomposites in the presence of E. coli and S. aureus bacteria. Drug release studies were performed using lidocaine drug and the results showed nearly similar drug release profile for all the samples except HAg3. Finally, nanocomposite HRA3 could be a suitable candidate for biomedical applications since it shows better biological and mechanical properties than GO and MWCNTs nanocomposites. Scheme illustrating the synthesis of Hap nanocomposites (Hap NCs) and their biological and mechanical assessments. [Display omitted] • Simple oil-bath mediated synthesis method was followed to prepare HAp nanocomposites. • All the nanocomposites prepared had a rod-like morphology of HAp which showed no morphological influences. • Superior antimicrobial activity was observed for nanocomposites, which contain Ag NPs against E. coli and S. aureus bacteria. • HRA3 showed excellent biological and mechanical properties due to its smooth structure and uniform distribution. [ABSTRACT FROM AUTHOR]

Abstract: A synthetic route is presented for the preparation of a silver film in presence of UV-radiation. Methoxy polyethylene glycol, a water-soluble polymer, was used as the reducing agent of the silver ions in the presence of an ultraviolet source to produce silver nanoparticles. During solution stirring, a centrifugal force was generated at the center of the solution. At this point on the surface of the solution, the nanoparticles coalesced to form a self-assembly of small subunits that ultimately develops into a film-like network. [Copyright &y& Elsevier]

In this study, we developed a method to prepare inorganic nanoparticles in situ on the surface of cationized cellulose using a rapid microwave-assisted synthesis. Selenium nanoparticles (SeNPs) were employed as a novel type of antimicrobial agent and, using the same method, silver nanoparticles (AgNPs) were also prepared. The results demonstrated that both SeNPs and AgNPs of about 100 nm in size were generated on the cationized cellulose fabrics. The antibacterial tests revealed that the presence of SeNPs clearly improved the antibacterial performance of cationized cellulose in a similar way as AgNPs. The functionalised fabrics demonstrated strong antibacterial activity when assessed using the challenge test method, even after repeated washing. Microscopic investigations revealed that the bacterial cells were visually damaged through contact with the functionalised fabrics. Furthermore, the functionalised fabrics showed low cytotoxicity towards human cells when tested in vitro using an indirect contact method. In conclusion, this study provides a new approach to prepare cationic cellulose fabrics functionalised with Se or Ag nanoparticles, which exhibit excellent antimicrobial performance, low cytotoxicity and good laundry durability. We have demonstrated that SeNPs can be a good alternative to AgNPs and the functionalised fabrics have great potential to serve as an anti-infective material. Unlabelled Image • In situ microwave-assisted synthesis of Se or Ag nanoparticles on cationized surface. • Se nanoparticles were effective against Gram-positive and Gram-negative strains. • Cationic groups and inorganic nanoparticles offer combined antimicrobial activities. • Antibacterial activity of Se and Ag modified fabrics retains after repeated washing. • Se nanoparticles a good alternative to Ag for developing an anti-infective material. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) have a wide antimicrobial spectrum and low incidence of resistance. They have been widely incorporated into wound dressings for antimicrobial purpose. However, these wound dressings suffer from the accompanied cytotoxicity. It is important but challenging for them to reduce the cytotoxicity without compromising antimicrobial activity, while the affecting factors are unknown. In this work, we incorporated AgNPs into starch nanofiber mats with the in situ reduction method, and investigated the structure and property of the composite nanofiber mats in detail. We found that the cytotoxicity and antibacterial activity of the starch/AgNPs composite nanofiber mats are both affected by the release behavior of silver from the mats, while of various stages and governing factors. The cytotoxicity of the mats depends on the silver release rate at the early stage, which is governed by both the size and content of the AgNPs. The antibacterial activity is more related to the silver release rate at the later stage and is determined mainly by the content of AgNPs. By optimizing the size and content of AgNPs, we found a safe window and obtained starch/AgNPs composite nanofiber mats with good antibacterial activity and excellent cytocompatibility as well. The composite nanofiber mats also showed moderate wet strength (1–2 MPa), high liquid absorption capability (19–34 times of their own weights) and suitable vapor permeability [0.22–0.26 g/(cm2·24 h)]. These starch/AgNPs composite nanofiber mats are ideal candidates for the treatment of infected and exuding wounds. Unlabelled Image • AgNPs were incorporated into starch nanofiber mats with in situ reduction method. • The size and content of AgNPs together controlled the release behavior of silver. • The size and content of AgNPs governed the cytotoxicity of the mats. • The content of AgNPs determined the antibacterial activity of the mats. • The mats showed good antibacterial property and excellent cytocompatibility. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) alloys present great potential for the development of orthopedic implants, whereas, their high degradation rate and poor antibacterial performance have restricted orthopedic applications. In this work, PLLA/GO-AgNP (poly-L-lactic acid/graphene oxide- silver nanoparticle) with different concentration of GO-AgNPs were deposited on Mg alloy via electrospinning method for enhancement of corrosion resistance and antibacterial performance. The result revealed that incorporation of GO into PLLA fibrous considerably slowed down the degradation rate of Mg alloy substrate and reduced the H 2 release rate from the substrate. Also, co-incorporation of GO and AgNPs into PLLA fibrous resulted in substantial escalate in compressive strength after immersion in simulated body fluid (SBF). Antibacterial activity test exhibited that Mg alloy and neat PLLA fibrous presented minimal inhibition area toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In contrast, using PLLA/GO-AgNPs fibrous improved antibacterial performance against both bacteria. Cytocompatibility results indicated that PLLA/GO-AgNPs fibrous with a low amount of GO-AgNPs enhanced cell proliferation and growth while high co-incorporation of GO-AgNPs showed a negative effect on cell proliferation. Taken together, PLLA/1GO-AgNPs fibrous coating shows suitable corrosion resistance, cytocompatibility, and antibacterial function for use in orthopedic applications. Unlabelled Image • Multifunctional PLLA/GO-Ag fibrous layers were prepared on Mg-Ca-Zn alloy using the electrospinning method. • PLLA/GO-Ag fibrous coating results in superior corrosion resistance and cytocompatibility than uncoated Mg alloy. • Antibacterial performance of fibrous layers increases with increasing GO-Ag concentration. • Corrosion and antibacterial mechanism of the fibrous-coated Mg-Ca-Zn alloy is proposed. [ABSTRACT FROM AUTHOR]

Here we report silver incorporated anatase TiO 2 developed on Ti metal by H 2 O 2 -AgNO 3 and heat treatment to have faster biomineralisation or apatite-forming ability in simulated body fluid (SBF). Apatite-forming ability has been investigated concerning heat treatment temperatures ranges, 400–800 °C and duration of soaking period in SBF. The apatite formation showed an increasing trend with increase in the heat treatment temperatures up to 600 °C and beyond that the Ti metal lost this ability. XRD as wells as Raman results of such chemical and heat-treated Ti metal at different temperatures further correlates the apatite nucleation directly in relation with that of anatase to rutile TiO 2 formation. Further, a time dependent apatite mineralisation study by XPS revealed simultaneous calcium and phosphate deposition at the early stage of soaking in SBF. Therefore, the apatite nucleation in the present chemically treated Ti metal depends on the crystalline phase of TiO 2 formed by H 2 O 2 and heat treatment along with Ag+ ion release. • Mechanistic study on the bioactivity of silver incorporated Ti metal • Ag addition gives good bioactivity at the same time efficient antibacterial activity for Ti metal. • Crystalline nature of TiO 2 and Ag+ ion release are the major factor which induces bioactivity. [ABSTRACT FROM AUTHOR]

Nanosilver immobilized on TiO 2 nanometric fibers (Ag/TiO 2) was produced by solution blow spinning and characterized using scanning electron microscopy, transmission electron microscopy, N 2 adsorption/desorption, X-ray diffraction, X-ray photoelectron spectroscopy, water contact angle, and inductively coupled plasma emission spectroscopy analyses. The in vitro antimicrobial and anticancer activities of the produced nanofibers was also investigated. Ag/TiO 2 nanofibers revealed a crystalline structure compatible with the rutile crystalline phase, as well as a mesoporous and superhydrophilic nature. XPS profiles showed Ti4+ and Ag0, indicating a strong interaction between the Ag nanoparticles and TiO 2. The Ag/TiO 2 nanofibers presented antimicrobial activity against Staphylococcus aureus , Enterococcus faecalis , and Escherichia coli. The release of silver ions from 5 mg∙mL−1 and 50 mg∙mL−1 of Ag/TiO 2 nanofibers was approximately 0.08 μg∙mL−1 and 0.18 μg∙mL−1, respectively. The nanofiber cytotoxicity in both macrophages (ATCC RAW 264.7) and cancer cells (murine AT-84 oral squamous carcinoma cells) was dose-dependent. A concentration of 5 mg∙mL−1 induced partial suppression growth and migration of cancer cells, while a concentration of 50 mg∙mL−1 resulted in complete inhibition of proliferation and migration of murine AT-84 cells. The overall results indicate that Ag/TiO 2 nanofibers can selectively inhibit the cellular mechanism of AT-84 by apoptosis with DNA damage and cell death. The antimicrobial and anticancer performance of Ag/TiO 2 nanofibers is probably the result of its nanometric dimension, high surface reactivity, and the interaction between TiO 2 and Ag. Electron transfer at the metal–semiconductor interface and reactive oxygen species production, in addition to the biological activity of released silver ions, confirm the potential for use as an agent in antimicrobial and anticancer therapy. Unlabelled Image • Antitumor and antimicrobial Ag/TiO 2 nanofibers were successfully produced by SBS. • Ag/TiO 2 nanofiber mats were efficient against S. aureus , E. faecalis , and E. coli. • Ag/TiO 2 nanofibers exhibited significant toxicity against AT-84 cancer cells. • Ag0 on the TiO 2 surface contributed to high performance of Ag/TiO 2 nanofibers. • Ag/TiO 2 nanofibers have a strong potential for local cancer therapy. [ABSTRACT FROM AUTHOR]