Abstract
Silver nanoparticles (AgNPs) were extensively used in different fields worldwide. There is a continued increase in their productions to fulfill various uses. Biological and chemical AgNP syntheses were the most popular mechanisms in this field. Agrowastes are rich in proteins, phenolics, and flavonoids that could act as bioreductant agents in AgNP biological synthesis. The present study was aimed at synthesizing AgNPs via chemical and biological methods using trisodium citrate, pomegranate fruit peel, and coffee ground waste extracts. Moreover, silver nanoparticles were monitored by UV-vis spectroscopy and characterized using zeta potential, size distribution mean, scanning electron microscope (SEM), X-ray diffractometer (XRD), and Fourier transforms infrared spectroscopy (FTIR). Four pathogenic bacterial strains (Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, and MRSA) were used to assess the antimicrobial effect of the synthesized AgNPs (2, 4, and 8 mg/ml). Results report the successful formation of silver nanoparticles chemically (AgNPs_Chem) and biologically by using pomegranate peel extract (AgNPs_PPE) and coffee ground waste extract (AgNPs_CE) due to the change of color to dark brown that is confirmed by UV-vis sharp absorption spectra at specific wavelengths. Characterization using SEM and XRD revealed their crystalline shape with a mean size of AgNPs _ Chem = 62.75 , AgNPs _ CE = 273.7 nm , and AgNPs _ PPE = 591.9 nm . AgNPs_Chem show higher negativity of zeta potential (−46.7 mV) than AgNPs_CE (−12.6 mV), followed by AgNPs_PPE (−7.98 mV), which had the least stability. All the synthesized AgNPs show antimicrobial potential on all selected strains. However, 8 mg/ml shows the most effective concentration and has more efficiency on K. pneumoniae than others. Overall, the results highlight that the use of agrowastes could be an ecofriendly way to synthesize AgNPs biologically that have the same antimicrobial effect as the chemically synthesized AgNPs.
Highlights
Owing to the extensive applications of nanomaterials in various areas of industry, technology, and agriculture along with medicine, the worldwide request for nanomaterials is increasing exponentially
We have provided a green, simple, and economic method for silver nanoparticle synthesis with the help of pomegranate peel and coffee ground extracts
A chemical reduction method was used for Ag nanoparticle (AgNP) synthesis by the help of trisodium citrate
Summary
Owing to the extensive applications of nanomaterials in various areas of industry, technology, and agriculture along with medicine, the worldwide request for nanomaterials is increasing exponentially. Due to the commercial consumption of silver nanoparticles (AgNPs) in various applications, the annual increase in AgNP production was estimated to be hundreds of tons worldwide [1]. In chemical preparation methods, producing stable colloidal AgNPs of desired sizes within the nanometer scale, apart from being an expensive chemical, can generate oxidized species during the synthesis process, which cannot be separated from the nanomaterial product [2]. Such the undesirable chemical entities can significantly restrict the application opportunities as well as the biological compatibility of the produced nanomaterials.
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