Biological activity of silver nanoparticles synthesized using viticultural waste.

This research paper presents a novel approach to the green synthesis of silver nanoparticles (AgNPs) using viticultural waste, allowing to obtain NP dispersions with distinct properties and morphologies (monodisperse and polydisperse AgNPs, referred to as mAgNPs and pAgNPs) and to compare their biological activities. Our synthesis method utilized the ethanolic extract of Vitis vinifera pruning residues, resulting in the production of mAgNPs and pAgNPs with average sizes of 12 ± 5 nm and 19 ± 14 nm, respectively. Both these AgNPs preparations demonstrated an exceptional stability in terms of size distribution, which was maintained for one year. Antimicrobial testing revealed that both types of AgNPs inhibited either the growth of planktonic cells or the metabolic activity of biofilm sessile cells in Gram-negative bacteria and yeasts. No comparable activity was found towards Gram-positives. Overall, pAgNPs exhibited a higher antimicrobial efficacy compared to their monodisperse counterparts, suggesting that their size and shape may provide a broader spectrum of interactions with target cells. Both AgNP preparations showed no cytotoxicity towards a human keratinocyte cell line. Furthermore, in vivo tests using a silkworm animal model indicated the biocompatibility of the phytosynthesized AgNPs, as they had no adverse effects on insect larvae viability. These findings emphasize the potential of targeted AgNPs synthesized from viticultural waste as environmentally friendly antimicrobial agents with minimal impact on higher organisms.

Bimetallic nanoparticle production using Cannabis sativa and Vitis vinifera waste extracts.

The utilization of waste materials for the synthesis of nanoparticles has gained significant attention due to its potential for waste valorization and contribution to circular economy. In this study, bimetallic nanoparticles were produced using extracts derived from Cannabis sativa and Vitis vinifera waste, focusing on their green synthesis and antimicrobial activity against Gram-negative bacteria, specifically several strains of Pseudomonas aeruginosa. The Vitis vinifera canes and post-extraction waste from Cannabis sativa were processed using an ethanol extraction method. The extract was then mixed with silver nitrate and tetrachloroauric acid solution at different reagent ratios to optimize the synthesis process. The resulting bimetallic nanoparticles (AgAuNPs) were characterized using UV-vis spectrophotometry, transmission electron microscopy, atomic absorption spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The antimicrobial activity of the biosynthesized AgAuNPs was evaluated against various strains of Pseudomonas aeruginosa. The minimal inhibitory concentration (MIC) was determined using a microcultivation device, and the minimal bactericidal concentration (MBC) was determined through subsequent solid medium cultivation. Additionally, the minimal biofilm inhibitory concentration (MBIC) was assessed using a polystyrene microtiter plate as biofilm carrier and measured through an assay determining the metabolic activity of biofilm cells. The results demonstrated successful synthesis of bimetallic nanoparticles using the extracts from Cannabis sativa and Vitis vinifera waste. The AgAuNPs exhibited significant antimicrobial activity against the tested Pseudomonas aeruginosa strains, inhibiting their growth and biofilm formation. These findings highlight the potential of waste valorization and circular economy in nanoparticle production and their application as effective antimicrobial agents. This study contributes to the growing field of sustainable nanotechnology and provides insights into the utilization of plant waste extracts for the synthesis of bimetallic nanoparticles with antimicrobial properties. The findings support the development of eco-friendly and cost-effective approaches for nanoparticle production while addressing the challenges of waste management and combating microbial infections.

Antibiofilm activity of silver nanoparticles biosynthesized using viticultural waste.

Green methods have become vital for sustainable development of the scientific and commercial sphere; however, they can bring new challenges, including the need for detailed characterization and elucidation of efficacy of their products. In this study, green method of silver nanoparticles (AgNPs) production was employed using an extract from grapevine canes. The aim of the study was to contribute to the knowledge about biosynthesized AgNPs by focusing on elucidation of their antifungal efficiency based on their size and/or hypothesized synergy with bioactive substances from Vitis vinifera cane extract. The antifungal activity of AgNPs capped and stabilized with bioactive compounds was tested against the opportunistic pathogenic yeast Candida albicans. Two dispersions of nanoparticles with different morphology (characterized by SEM-in-STEM, DLS, UV-Vis, XRD, and AAS) were prepared by modification of reaction conditions suitable for economical production and their long-term stability monitored for six months was confirmed. The aims of the study included the comparison of the antifungal effect against suspension cells and biofilm of small monodisperse AgNPs with narrow size distribution and large polydisperse AgNPs. The hypothesis of synergistic interaction of biologically active molecules from V. vinifera extracts and AgNPs against both cell forms were tested. The interactions of all AgNPs dispersions with the cell surface and changes in cell morphology were imaged using SEM. All variants of AgNPs dispersions were found to be active against suspension and biofilm cells of C. albicans; nevertheless, surprisingly, larger polydisperse AgNPs were found to be more effective. Synergistic action of nanoparticles with biologically active extract compounds was proven for biofilm cells (MBIC80 20 mg/L of polydisperse AgNPs in extract), while isolated nanoparticles suspended in water were more active against suspension cells (MIC 20 mg/L of polydisperse AgNPs dispersed in water). Our results bring new insight into the economical production of AgNPs with defined characteristics, which were proven to target a specific mode of growth of significant pathogen C. albicans.

Antimicrobial properties and applications of metal nanoparticles biosynthesized by green methods.

There is a growing interest in the potential and application of metal nanoparticles across many fields. A vast array of techniques for metal nanoparticle synthesis has been discovered; however, sustainability, cost-effectiveness, and environmental concerns favor the green biological approach, using various plant and microbial sources. This review describes the diversity in green methods for nanoparticle biosynthesis, antimicrobial properties of metal nanoparticles and their potential applications. Metal nanoparticle biosynthesis by extracts and solutions obtained from plants, bacteria, fungi and templates such as viruses are discussed. As biosynthesized nanoparticles have been proven to possess antibacterial, antifungal, and even antiviral properties, these are discussed in detail, with silver and gold nanoparticles as the most studied and with the highest potential for medical application. The focus on prospective antimicrobial applications of nanoparticles stems from the arising resistance of many serious pathogens to traditional disinfectants and antibiotics. Other fields for the application of biosynthesized nanoparticles are also stated briefly, such as in agriculture as pesticides, in wastewater treatment and bioremediation. Finally, the limitations and safety issues connected with widespread use of nanoparticles are discussed.