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Abstract Due to their remarkable antibacterial properties, silver nanoparticles (Ag NPs) and curcumin (CCM) have been widely used in the antimicrobial field. In our study, we have fabricated the uniform and stable silver/curcumin composite nanoparticles by a facile ultrasound treatment process and the synergistic antibacterial activity were evaluated. The curcumin not only played a role of reducing agent but also acted as a capping agent. The antibacterial effects of silver/curcumin (cAgNPs) were studied by measuring the growth curve and surface plate assay based on the E. coli and B. subtilis , which showed concentration dependent bacteriostatic and bactericidal effects of cAgNPs. The presence of CCM enhance the binding of Ag to bacterial membrane and Ag+ release in comparison to that without CCM, so that creating a temporary and local high Ag+ concentration near the surface of the bacterium, meanwhile, generation of more reactive oxygen species, lead to membrane damage, bacterial lipases and induce leakage of intracellular contents followed by bacterial death that lead to growth inhibition of the bacteria. The antibacterial effects were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), the effect which were further found to decrease by introducing antioxidant N -acetyl- l -cysteine (NAC) act as a reactive oxygen species (ROS) scavenging agent. These initial data suggest that cAgNPs have a highly antibacterial efficient and might have potential to be developed as an effective antimicrobial nanomaterial. Highlights • Curcumin not only played a role of reducing agent but also acted as a capping agent; • Curcumin enhance the binding of Ag to bacterial membrane and Ag+ release; • Creating a temporary and local high Ag+ concentration near the surface of the bacterium; • Generation of more reactive oxygen species, lead to membrane damage, bacterial lipases and intracellular contents leakage. [ABSTRACT FROM AUTHOR]

Abstract Biological synthesis involves the reduction and stabilization of metal ions using different types of organisms. Plants are an attractive source for silver nanoparticles (Ag NPs) synthesis because of their strong reducing potentials by production of a wide range of secondary metabolites. The present study describes the biosynthesis of Ag NPs using plant extract of Ocimum basilicum extract grown under in vitro condition for the first time. The surface Plasmon resonance found at 450 nm confirmed the formation of Ag NPs. FESEM images revealed relatively spherical- shaped of Ag NPs. The biosynthesized Ag NPs were crystalline in nature with mean diameter about 13.82 nm. FTIR results expounded the functional groups of plant extract responsible for the bio-reduction of silver ions and the interactions between them. The obtained nanoparticles showed good inhibitory activity against both Gram positive and Gram negative bacteria. These results suggest that with changes in plant's culture condition it may be possible to obtain nanoparticles with desired characteristics. Highlights • Biosynthesis of silver nanoparticles using plant extract of Ocimum basilisum grown in vitro • Characterization of biosynthesized Ag NPs by equipment • Identification of proteins, phenols and flavonoids as responsible plant metabolites in bio-reduction of Ag+ • Observation thin layer of biomolecules on the surface of the Ag NPs in FESEM images required for biocompatible function of Ag NPs • High antibacterial potential of Ag NPs [ABSTRACT FROM AUTHOR]

Abstract Silver nanoparticles (Ag NPs) serve numerous chief functions in cosmetics, engineering, textile, food technology and medicine. These nanoparticles are also utilized in the pharmaceutical industry particularly in the production of novel antimicrobial agents. However, despite the various studies of Ag NPs induced toxicity, there is a lack of information concerning cellular toxicity mechanisms of these nanoparticles on human cells. In the current project, we investigate the anti-cancer effects of Ag NPs in HepG2 (liver hepatocellular adenocarcinoma) cells. The mean particle size and morphology for the prepared nanoparticles were determined by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. Cell viability, reactive oxygen species (ROS) formation, cytochrome c amount and expression level of BAX/CASP 3/CASP 8/CASP 9 were assayed in HepG2 cells after incubation with Ag NPs. The prepared nanoparticles showed the mean particle size of 30.71 nm with polydispersity index (PDI) of 0.21. Our results revealed decreased cell viability in a concentration-dependent manner and the IC50 of 75 μg/mL for Ag NPs. Ag NPs cytotoxicity was associated with induction of ROS and cell apoptosis in HepG2 cell line. According to our findings, Ag NPs could be considered as potential chemotherapeutic agents in the treatment of liver hepatocellular carcinoma. Highlights • The proposed size of nanoparticle is about 30 nm. • Anti-cancer effects of Ag-NPs were tested with in vitro assays in HepG2 cells. • Hepatocellular carcinoma cell proliferation was inhibited via the induction of cytotoxicity and apoptosis. [ABSTRACT FROM AUTHOR]

Bacterial infection and damage caused by dressing removal are two concerning problems which prolong the healing process in treatment of skin injuries. In this study, plasma treated electrospun polycaprolactone (PCL) scaffold was coated with silver nanoparticles (AgNPs) embedded in gelatin (Gel) by multi-immersion technique to optimize its antibacterial performance and reduce wound-scaffold adhesion. Water interaction test was used to examine the hydrophilization of PCL electrospun fibers after plasma treatment. Scanning Electron Microscopy (SEM) and weight calculation were employed to investigate the morphology and absorptive ability of the GelAg multi-coated PCL membrane (EsPCLGelAg). Antibacterial property of the membrane was evaluated using agar diffusion method against gram positive and gram negative bacteria. Mice model was also used to examine the efficiency of the membrane in healing process and its ability to prevent damage of newly formed tissue when peeling off. SEM results showed that the thickness of GelAg layer on EsPCL membrane increases correspondingly to the number of coating times. In vitro and in vivo data also demonstrated that the greater number of GelAg coating times, the more significant the antibacterial property of the membrane while not sticking to the wound site. These results suggest that multi-coating technique can be applied to optimize the antibacterial property of EsPCLGelAg scaffold and prevent removal-induced damage for wound dressing applications. [ABSTRACT FROM AUTHOR]

Oral cavity is a gateway to the entire body and protection of this gateway is a major goal in dentistry. Plaque biofilm is a major cause of majority of dental diseases and although various biomaterials have been applied for their cure, limitations pertaining to the material properties prevent achievement of desired outcomes. Nanoparticle applications have become useful tools for various dental applications in endodontics, periodontics, restorative dentistry, orthodontics and oral cancers. Off these, silver nanoparticles (AgNPs) have been used in medicine and dentistry due to its antimicrobial properties. AgNPs have been incorporated into biomaterials in order to prevent or reduce biofilm formation. Due to greater surface to volume ratio and small particle size, they possess excellent antimicrobial action without affecting the mechanical properties of the material. This unique property of AgNPs makes these materials as fillers of choice in different biomaterials whereby they play a vital role in improving the properties. This review aims to discuss the influence of addition of AgNPs to various biomaterials used in different dental applications. [ABSTRACT FROM AUTHOR]

Silver nanoparticle has been widely applied to a variety of fields for its outstanding antimicrobial activity. However, the stability of silver nanoparticle limits its application under certain conditions. Thus, improving the stability of silver nanoparticle via biosynthesis is a promising shortcut to expand its application. Sericin from silkworm cocoon has good hydrophilicity, reaction activity, biocompatibility and biodegradability. In this study, we developed a novel, simple, one-step biosynthesis method to prepare sericin-silver nanoparticle composite in situ in solution. Sericin served as the reductant of silver ion, the dispersant and stabilizer of the prepared sericin-silver nanoparticle composite. Natural light was the only power source used to catalyze the synthesis of silver nanoparticle in situ in solution. The novel sericin-silver nanoparticle composite was characterized by ultraviolet-visible and fluorescence spectroscopy, X-ray diffraction, transmission electron microscopy and fourier transform infrared spectroscopy. The results showed silver nanoparticle could be synthesized through the reduction of AgNO 3 by the phenolic hydroxyl group of tyrosine residues of sericin under the catalysis of natural light. The synthesized silver nanoparticle had good crystalline, size distribution and long-term stability at room temperature. Light irradiation was essential for the preparation of sericin-silver nanoparticle composite. The antibacterial activity assay showed 25 mg/L and 100 mg/L were the minimum concentrations of sericin-silver nanoparticle composite required to inhibit the growth of Staphylococcus aureus and kill this bacterium, respectively. The cytotoxicity assay showed cell viability and cell growth were almost not affected by sericin-silver nanoparticle composite under the concentration of 25 mg/L. Our study suggested the preparation of sericin-silver nanoparticle composite was environmentally friendly and energy conservation, and the prepared sericin-silver nanoparticle composite had long-term stability, effective antibacterial activity and good biocompatibility. This novel sericin-silver nanoparticle composite has shown great potentials for biomedical application such as antibacterial agent and wound care. [ABSTRACT FROM AUTHOR]

In this study, composite antibacterial microcapsules combining of two antibacterial agents: chlorhexidine acetate and silver nanoparticle were prepared. The chlorhexidine acetate was encapsulated inside of the microcapsules and nano-sized silver particles were modified on the surface of microcapsules by electrostatic adsorption methods. Results show that this method decreases the silver usage dramatically, and promises a sustained antibacterial effect > 30 days. These microcapsules can also be modified on the surface of polymer films easily, which demonstrated the potential in functionalizing the implanted materials with antibacterial property. [ABSTRACT FROM AUTHOR]

The creation of an antibacterial material with triggerable properties enables us to avoid the overuse or misuse of antibacterial substances and, thus, prevent the emergence of resistant bacterial strains. As a potential light-activated antibacterial material, polymethylmethacrylate (PMMA) nanofibers doped with silver nanoparticles (AgNPs) and meso -tetraphenylporphyrin (TPP) were prepared by electrospinning. TPP was chosen as an effectively reactive oxygen species (ROS) producer. Antibacterial tests on Staphylococcus epidermidis ( S. epidermidis ) and Enterococcus faecalis (E. faecalis) showed the excellent light-triggerable antibacterial activity of the doped materials. Upon light irradiation at the wavelength corresponding to the TPP absorption peak (405 nm), antibacterial activity dramatically increased, mostly due to the release of AgNPs from the polymer matrix. Furthermore, under prolonged light irradiation, the AgNPs/TPP/PMMA nanofibers, displayed enhanced longevity and photothermal stability. Thus, our results suggest that the proposed material is a promising option for the photodynamic inactivation of bacteria. [ABSTRACT FROM AUTHOR]

A novel, elastic, non-adhesive and antimicrobial hydrogel PVA scaffold (loaded with AgNPs) synthesized using freeze-thaw method has been characterized in this study. The direct visualization of the as synthesized (one-pot green synthesis methodology) AgNPs using TEM shows particle size in the range of 7 ± 3 nm. The minimum inhibitory concentration (MIC) of AgNPs for Staphylococcus aureus and Escherichia coli was estimated to be 7.81 μg/mL, whereas for Pseudomonas aeruginosa (gram negative) it was around 3.90 μg/mL. The antimicrobial efficacy of AgNPs was further studied by protein leakage, ROS and LDH activity assay. The quantitative elemental analysis of silver was calculated before and after release in phosphate buffer (pH-7.4) by atomic absorption spectroscopy. The antimicrobial efficacy of the scaffold was retained even after 96 h of release of AgNPs which suggests that the scaffold can be used as a reservoir for AgNPs to maintain a moist and sterile environment for a long period of time. [ABSTRACT FROM AUTHOR]

Herein, we reported an interpenetrating polysaccharide-based hydrogel in which carboxymethyl chitosan (CMC) chains were physically dispersed throughout the thermoplastic elastomer gel network has been developed as a versatile platform for precisely controlled synthesis of nanometals. Results indicated the interpenetrated CMC chains could serve as multifunctional fillers for metal ions adsorption and stabilization while the thermally reconfigurable agarose (Agar) gel medium provides three-dimensional semi-solid framework for entrapping and recollecting of the fabricated nanometals. Specifically, the CMC chains were found to strongly coordinate with silver ions as a dynamically responsive metal-biopolymer complex within the bulk gel network as confirmed by the enhanced mechanical properties and regulated shape memory performances. Moreover, by varying CMC concentrations and coupling with a layer-stacking approach, multiple biochemical gradients could be facilely generated for in-situ synthesis of silver nanoparticles, achieving a narrow size of ~7 nm, confined sphere-shape and high concentrations. The monodispersed nanometals are confirmed to be highly active (e.g., considerable catalytic performance), and which could be easily recycled from the bulk gel system via a heating treatment. Thus, this work would provide a generic methodology for the multifunctional metallogel assembly and great possibility for controllable and largescale synthesis of noble nanometals toward biomedical applications. • The hydrogel was prepared by interpenetrating carboxymethyl chitosan into agarose framework. • Metal ions reinforced swelling behavior and shape memory property have been demonstrated. • Carboxymethyl chitosan chain can mediate precisely synthesis of Ag nanoparticles (~7 nm). • Nanometals are active in the gel system and could be easily recycled for further uses. [ABSTRACT FROM AUTHOR]

Calcium carbonate is used as bone-filling material due to its good biocompatibility, bioactivity, and bioabsorbability, but the prevalence of infectious complications associated with calcium carbonate has created a persisting challenge in the treatment of bone defect. Therefore, this greatly necessitate the need to endow calcium carbonate with antibacterial properties. In this study, calcium carbonate powders loaded with silver nanoparticles (Ag-CaCO 3) were prepared in attempt to serve as a novel antibacterial inorganic filler material. This objective was achieved using ultrasonic spray-pyrolysis (USSP) route to produce Ag-CaCO 3 with 1, 5 and 10 mol% silver. The size of silver nanoparticles on CaCO 3 microspheres could be regulated by adjusting silver concentration to facilitate effective release of Ag+ ions. This was demonstrated in Ag-CaCO 3 (1), where the lowest silver content at 1 mol% achieved the highest Ag+ ions release over 28 days. This in turn gave rise to effective antibacterial efficiency against Staphylococcus aureus and Escherichia coli. Furthermore, CaCO 3 (1) could also support osteoblast-like cells (MG-63) at a cell viability of 80%. Overall, this work extends the capabilities in employing USSP to produce inorganic filler materials with sustained antibacterial properties, bringing one step closer to the development of antibacterial products. • Ag nanoparticles loaded CaCO 3 were prepared by ultrasonic spray-pyrolysis route. • Size of Ag nanoparticles was regulated to facilitate effective release of Ag+ ions. • Ag nanoparticles loaded CaCO 3 displayed killing of bacteria with minimum cytotoxicity. [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]

In this study, silver nanoparticles (Ag NPs) was eco-friendly synthesized using purified flavonoid rich content of Morinda citrifolia (M. citrifolia) extract. The synthesized Ag NPs was exhibited at 420 nm in UV-spectrometer, and surface morphology with available chemical composition, shape and size of the Ag NPs were confirmed by X-ray diffraction (XRD) variation, scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX) and transmission electron microscope (TEM). In addition, the excellent phytochemicals and anti-oxidant activity of the Ag NPs were confirmed by total anti-oxidant and DPPH free radical scavenging assays. Further, the concentration dependent inhibition of synthesized Ag NPs against biofilm forming Staphylococcus aureus (S. aureus) was confirmed by minimum inhibition concentration (MIC). The growth cells were arrested in the log phase of the culture and detected by flow cytometry analysis. In addition, the bacterial viability, exopolysaccharide degradation, intracellular membrane damage, matured biofilm inhibition, architectural damage and morphological alteration were confirmed by confocal laser scanning electron microscope (CLSM) and SEM. Furthermore, the synthesized Ag NPs reacted with methylene blue (MB) dye molecules has 100% degradation at an irradiation time of 140 min. Conclusively, the eco-friendly synthesized Ag NPs has excellent anti-oxidant, anti-bacterial through intracellular membrane damage, cell cycle arrest and methylene blue dye removal. Unlabelled Image • Anti-bacterial and photo-catalysis activity of Ag NPs against S. saprophyticus BDUMS 5 (MN310601). • Decreased cells and intracellular damages of Ag NPs treated bacteria was confirmed by flow cytometer and CLSM. • Morphological damage of Ag NPs treated bacteria showed by SEM and TEM [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) materials loaded with silver nanoparticles (AgNPs) have drawn considerable attention due to their capacity to efficiently inactivate bacteria though a multifaceted mechanism of action, as well as for presenting a synergetic effect against bacteria when compared to the activity of AgNPs and GO alone. In this investigation, we present an inexpensive and environmentally-friendly method for synthesizing reduced GO sheets coated with silver nanoparticles (AgNPs/r-GO) using a coffee extract solution as a green reducing agent. The physical and chemical properties of the produced materials were extensively characterized by scanning electron microscopy (SEM), field-emission gun transmission electron microscopy (FEG-TEM), ultraviolet and visible absorption (UV–Vis), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-optical emission spectroscopy (ICP-OES) and ion release determination. The results demonstrated that AgNPs/r-GO composites were successfully produced, revealing the formation of micrometer-sized r-GO sheets decorated by AgNPs of approximately 70 nm diameter. Finally, bactericidal and photobactericidal effects of the AgNPs/r-GO composites were tested against Staphylococcus aureus , in which the results showed that the composites presented antimicrobial and photoantimicrobial activities. Moreover, our results demonstrated for the first time, to our knowledge, that an efficient process of bacterial inactivation can be achieved by using AgNPs/r-GO composites under blue light irradiation as a result of three different bacterial killing processes: (i) chemical effect promoted by Ag+ ion release from AgNPs; (ii) photocatalytic activity induced by AgNPs/r-GO composites, enhancing the bacterial photoinactivation due to the excited-Plasmons of the AgNPs when anchored on r-GO; and (iii) photodynamic effect produced by bacterial endogenous photosensitizers under blue-light irradiation. In summary, the present findings demonstrated that AgNPs/r-GO can be obtained by a non-toxic procedure with great potential for biomedical-related applications. Unlabelled Image • AgNPs and AgNPs/r-GO composites were prepared by an environmentally-friendly, efficient, and inexpensive method. • Coffee extract was used as a green reducing agent for obtaining AgNPs and AgNPs/r-GO composites. • Bactericidal and photobactericidal effects of AgNPs and AgNPs/r-GO were tested against staphylococcus aureus. • An effective killing of bacteria under blue-light illumination was achieved. • Blue-light irradiation enhanced the antimicrobial activity of AgNPs/r-GO when compared to the AgNPs and GO alone. [ABSTRACT FROM AUTHOR]

Wounds associated with diabetes mellitus are the most severe co-morbidities, which could be progressed to cause cell necrosis leading to amputation. Statistics on the recent status of the diabetic wounds revealed that the disease affects 15% of diabetic patients, where 20% of them undergo amputation of their limb. Conventional therapies are found to be ineffective due to changes in the molecular architecture of the injured area, urging novel deliveries for effective treatment. Therefore, recent researches are on the development of new and effective wound care materials. Literature is evident in providing potential tools in topical drug delivery for wound healing under the umbrella of nanotechnology, where nano-scaffolds and nanofibers have shown promising results. The nano-sized particles are also known to promote healing of wounds by facilitating proper movement through the healing phases. To date, focuses have been made on the efficacy of silver nanoparticles (AgNPs) in treating the diabetic wound, where these nanoparticles are known to exploit potential biological properties in producing anti-inflammatory and antibacterial activities. AgNPs are also known to activate cellular mechanisms towards the healing of chronic wounds; however, associated toxicities of AgNPs are of great concern. This review is an attempt to illustrate the use of AgNPs in wound healing to facilitate this delivery system in bringing into clinical applications for a superior dressing and treatment over wounds and ulcers in diabetes patients. • Diabetes wounds are demanding special treatment attention. • Topical deliveries of nanoparticles have shown promising results in wound healing. • Silver nanoparticle exhibited potential anti-inflammatory and antibacterial properties. • Several clinical applications facilitate a superior dressing and treatment of wounds. [ABSTRACT FROM AUTHOR]

Biosynthesis of metal nanoparticles is expected as a cost efficient and ecofriendly option in the research study. Therefore, the aqueous extracts made from leaf of Aesculus hippocastanum (horse chestnut) were used as the reducing factors to synthesize silver nanoparticles (AgNPs) and their antioxidant, antibacterial and the application of resveratrol combined AgNPs as efficient delivery vehicles have also been evaluated. The biosynthesized AgNPs were characterized by UV–Visible Spectroscopy, Fourier-Transform Infrared Spectroscopy (FTIR), X Ray Diffraction (XRD), Zeta potential, and Scanning Electron Microscopy (SEM). The AgNPs were found to be stable at −29.1 mV through zeta potential study. According to the UV-Vis measurements, AgNP formation was observed at a wavelength range of 420–470 nm. The Ag NPs were spherical with a size of 50 ± 5 nm. AgNPs exhibited strong antibacterial activity against all tested bacterial species but have no effect against fungal strains. AgNPs showed an important inhibitive activity counter the DPPH radical and thereby indicate a source for antioxidants. The free radical scavenging activity of AgNP was calculated as 54.72% at the highest concentration (100 ppm). The superoxide radical scavenging activity of AgNPs was found to be increased with increasing concentrations and the average inhibition was about 62.9% as compared to the activity of plant extract. In vitro investigations on the drug delivery from AgNPs exhibited pH dependency; the release was significant (45.6%) below acidic terms (pH 5.2) when in proportion to physiological terms (pH7.4). It was observed that the resveratrol-combined to AgNPs stays on the nanoparticle surface for a lengthy time in the plasma at physiological pH (7.4), so very reducing the flank influence on the normal tissues. It can be concluded that horse chestnut leaves has reduction potential as well as being a capping agent to produce well-defined nanoscale silver particles. Our biosynthesized Ag NPs can be used antibacterial, antioxidant agent and also for as effective delivery vehicles in the near future. • Green synthesis of AgNPs using Aesculum hippocastanum leaf extract. • The synthesized nanoparticles were analyzed by FT-IR, XRD, Zeta Potantial and SEM. • Obtained AgNPs showed significant antioxidant and antimicrobial activities. • In vitro observations on the drug release from AgNPs exhibited pH dependency. [ABSTRACT FROM AUTHOR]