Biosynthesis of silver nanoparticles using Onosma sericeum Willd. and evaluation of their catalytic properties and antibacterial and cytotoxic activity

Biofabrication strategy of silver-nanodrug conjugated polyhydroxybutyrate degrading probiotic and its application as a novel wound dressing

Wound infections with rising incidences of multi-drug resistant bacteria are among the public health problems worldwide. The current study describes wound dressing materials made from biodegradable polyhydroxybutyrate (PHB) combined with AgNPs and gelatin (AgNPs/Gelatin/PHB). Microbial PHB was mixed with gelatin (1:2) to form a polymer matrix which was loaded with different concentrations of AgNPs (8.3-133 μg/mL). The statistical results of AgNPs synthesizing based on Box-Behnken design revealed that 1.247 mM silver nitrate and 24.054 % of Corchorus olitorius leaf extract concentration at pH (8.07) were the optimum values for the biosynthesis. UV-Vis spectroscopy, FTIR study and XRD reflects that nanoparticles are formed. The UV-Vis spectroscopy of Gelatin/PHB/AgNPs exhibited two specific bands at 298 nm and 371 nm, which confirm the formation of the conjugate. AgNPs had MICs and MBCs of (24.9, 24.9, and 12.45 μg/mL) and (33.25, 33.25, and 16.6 μg/mL) against (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). The MIC and MBC of AgNPs/Gelatin/PHB against the same tested bacteria were 31.1 μg and 41.5 μg, respectively. AgNPs/Gelatin/PHB exhibit excellent antimicrobial efficacy against bacteria. Sterilized gauze loaded with 31.1 μg of AgNPs/Gelatin/PHB acted as an effective wound dressing. Thus, the study highlights the importance of wound dressings developed from degradable AgNPs/Gelatin/PHB in enhancing antimicrobial efficiency and facilitating a better wound healing process.

Phyto-fabricated Nanoparticles and Their Anti-biofilm Activity: Progress and Current Status

Biofilm is the self-synthesized, mucus-like extracellular polymeric matrix that acts as a key virulence factor in various pathogenic microorganisms, thereby posing a serious threat to human health. It has been estimated that around 80% of hospital-acquired infections are associated with biofilms which are found to be present on both biotic and abiotic surfaces. Antibiotics, the current mainstream treatment strategy for biofilms are often found to be futile in the eradication of these complex structures, and to date, there is no effective therapeutic strategy established against biofilm infections. In this regard, nanotechnology can provide a potential platform for the alleviation of this problem owing to its unique size-dependent properties. Accordingly, various novel strategies are being developed for the synthesis of different types of nanoparticles. Bio-nanotechnology is a division of nanotechnology which is gaining significant attention due to its ability to synthesize nanoparticles of various compositions and sizes using biotic sources. It utilizes the rich biodiversity of various biological components which are biocompatible for the synthesis of nanoparticles. Additionally, the biogenic nanoparticles are eco-friendly, cost-effective, and relatively less toxic when compared to chemically or physically synthesized alternatives. Biogenic synthesis of nanoparticles is a bottom-top methodology in which the nanoparticles are formed due to the presence of biological components (plant extract and microbial enzymes) which act as stabilizing and reducing agents. These biosynthesized nanoparticles exhibit anti-biofilm activity via various mechanisms such as ROS production, inhibiting quorum sensing, inhibiting EPS production, etc. This review will provide an insight into the application of various biogenic sources for nanoparticle synthesis. Furthermore, we have highlighted the potential of phytosynthesized nanoparticles as a promising antibiofilm agent as well as elucidated their antibacterial and antibiofilm mechanism.

Silver Nanoparticles Biosynthesis, Characterization, Antimicrobial Activities, Applications, Cytotoxicity and Safety Issues: An Updated Review

Rapid advances in nanotechnology have led to its emergence as a tool for the development of green synthesized noble metal nanoparticles, especially silver nanoparticles (AgNPs), for applications in diverse fields such as human health, the environment and industry. The importance of AgNPs is because of their unique physicochemical and antimicrobial properties, with a myriad of activities that are applicable in various fields, including the pharmaceutical industry. Countries with high biodiversity require the collection and transformation of information about biological assets into processes, associations, methods and tools that must be combined with the sustainable utilization of biological diversity. Therefore, this review paper discusses the applicable studies of the biosynthesis of AgNPs and their antimicrobial activities towards microorganisms in different areas viz. medicine and agriculture. The confirmed antiviral properties of AgNPs promote their applicability for SARS-CoV-2 treatment, based on assimilating the virus’ activities with those of similar viruses via in vivo studies. In this review, an insight into the cytotoxicity and safety issues of AgNPs, along with their future prospects, is also provided.