Development of New Silver Nanoparticles Suitable for Materials with Antimicrobial Properties

Abstract

Silver nanoparticles are the most important nanoparticles in connection with the antimicrobial effect. Nowadays, the green synthesis of various types of nanoparticles is rapid, effective and produce less toxic nanoparticles often with specific properties. In our experiment we have developed and described in details various types of silver nanoparticles synthesized chemically or by the green synthesis. Nine different silver nanoparticles were synthesized, three by citrate method at different pHs (8; 9; 10), four using gallic acid at alkaline pHs (10; 11), and two by green synthesis using green tea and coffee extracts, both at pH 9. Characterisation of silver nanoparticles was performed using dynamic light scattering, scanning electron microscopy, and ultraviolet-visible absorption spectroscopy. Silver nanoparticles prepared by green synthesis showed the highest antioxidant activity and also ability for quenching of free radicals. Antibacterial activity of silver nanoparticles was determined on bacterial cultures such as Staphylococcus aureus and Escherichia coli. Silver nanoparticles synthesized using green tea and coffee extracts showed the highest antibacterial activity for both bacterial strains. Minimal inhibition concentration for both strains was found to be 65 M at each silver nanoparticle synthesized using green synthesis.

Biological synthesis of gold and silver nanoparticles using leaf extracts of Crassocephalum rubens and their comparative in vitro antioxidant activities

“…These properties are reportedly found with ascorbic acid, and is regarded as powerful scavenger of free radicals [29]. The result from this study supports the findings of Ruttkay-Nedecky et al [30], where biological method of synthesis (green synthesis) of silver nanoparticles using green tea and coffee extracts showed higher antioxidant and free radical quenching abilities when compared to citrate reduction method.…”

Eco-friendly silver nanoparticles (AgNPs) fabricated by green synthesis using the crude extract of marine polychaete, Marphysa moribidii: biosynthesis, characterisation, and antibacterial applications

“…The discrepancy in these results might be due to a particle size variance. It is well established that the SPR bands are very sensitive and highly dependent on the nanoparticles size, shape, AgNO 3 concentration and the type of biomolecules presented in the biological extract ( Raja et al., 2017 ; Ruttkay-nedecky et al., 2019 ).

Figure 3 UV-Vis absorption spectra of biosynthesised AgNPs, a negative control of AgNO 3 solution and commercial AgNPs (positive controls) by Sigma Aldrich.

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Biogenic Silver Nanoparticles (AgNPs) from Marphysa moribidii Extract: Optimization of Synthesis Parameters

“…According to the literature, the absorption band in the range of 380-450 nm in the UV-Vis spectra might be attributable to the AgNPs (Chowdhury et al, 2016;Vinayagam et al, 2018). Moreover, it is well established that SPR bands are susceptible to and highly dependent on the size and shape of the nanoparticles, the AgNO3 concentration, and the type of biomolecules presented in the biological extract (Raja et al, 2017;Ruttkay-nedecky et al, 2019). Figure 1 illustrates the mechanism of AgNP formation and the differences between solution colors of polychaete crude extract, AgNO3 solution, and biosynthesized AgNPs.…”