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• First ever report of Mucuna pruriens (L.) DC. callus mediated green synthesis of silver nanoparticles. • The seeds were germinated in-vitro in the modified Murashige and Skoog's medium and the in-vitro leaf was used as an explant to induce callus. • Callus was induced using various types of auxins and cytokinin's at different concentrations. The best responded callus was sub cultured and used for the study. • The antibacterial activity assay was performed against gram positive Bacilus velezensis (Accession no. MW219533) and gram-negative escherichia coli cultures. • highest antibacterial activity against E. coli (84.8%) and B. velezensis (78.1%) was shown by 0.5 mg/L pic and 2.0 mg/L BAP callus mediated AgNPs. In this paper, we describe the green synthesis of silver nanoparticles (AgNPs) using plant extracts, as well as their structural, optical, and antibacterial activities against Escherichia coli and Bacillus velezensis bacteria. For the study, several sections (root, leaves, and seed) of Mucuna pruriens , an immense medicinal herbal used to treat Parkinson's disease, were evaluated. Also, the seeds were grown in-vitro in the modified Murashige and Skoog's medium and the leaf derived callus supplemented by different phytohormones like picloram (pic), thidiazuron (TDZ), 6-benzylaminopurine (BAP) and 2-isopentenyl adenine (2-iP) were selected for this study. This is the first report of distinct callus obtained from M. pruriens and used for green nanoparticle synthesis. The prepared materials were thoroughly evaluated for structural and optical properties using XRD, FTIR, and UV-Visible spectroscopy. During synthesis, the colour changes from colourless to reddish brown, and the existence of an SPR peak in the absorption spectra confirms the formation of AgNPs. The FTIR spectra reveals the presence of phenolic group and alkyl ether groups, which were responsible for the reduction of silver ions during the green synthesis. The aqueous extracts of plant parts and callus obtained from different hormones showed very poor antibacterial activity. However, the green synthesized nanoparticles fabricated by different plant extracts showed good antimicrobial activity towards E. coli and B. velezensis bacteria. amongst the investigated results, highest antimicrobial activity against E. coli (84.8%) and B. velezensis (78.1%) was shown by AgNPs mediated by leaf extracts respectively followed by 0.5 mg/L pic and 2.0 mg/L BAP callus mediated silver nanoparticle solution. According to the findings, green produced AgNPs are promising candidates for antibacterial applications against E. coli and B. velezensis. [ABSTRACT FROM AUTHOR]

The production of pure silver nanoparticles (Ag-NPs) with unique properties remains a challenge even today. In the present study, the synthesis of silver nanoparticles (Ag-NPs) from natural pullulan (PL) was carried out using a radiation-induced method. It is known that pullulan is regarded as a microbial polysaccharide, which renders it suitable to act as a reducing and stabilizing agent during the production of Ag-NPs. Pullulan-assisted synthesis under gamma irradiation was successfully developed to obtain Ag-NPs, which was characterized by UV-Vis, XRD, TEM, and Zeta potential analysis. Pullulan was used as a stabilizer and template for the growth of silver nanoparticles, while gamma radiation was modified to be selective to reduce silver ions. The formation of Ag-NPs was confirmed using UV–Vis spectra by showing a surface plasmon resonance (SPR) band in the region of 410–420 nm. As observed by TEM images, it can be said that by increasing the radiation dose, the particle size decreases, resulting in a mean diameter of Ag-NPs ranging from 40.97 to 3.98 nm. The XRD analysis confirmed that silver metal structures with a face-centered cubic (FCC) crystal were present, while TEM images showed a spherical shape with smooth edges. XRD also demonstrated that increasing the dose of gamma radiation increases the crystallinity at a high purity of Ag-NPs. As examined by zeta potential, the synthesized Ag-NP/PL was negatively charged with high stability. Ag-NP/PL was then analysed for antimicrobial activity against Staphylococcus aureus, and it was found that it had high antibacterial activity. It is found that the adoption of radiation doses results in a stable and green reduction process for silver nanoparticles. [ABSTRACT FROM AUTHOR]

In the present study, we have developed a green approach for the synthesis of silver nanoparticles (DSAgNPs) using aqueous extract of Durio zibethinus seed and determined its antibacterial, photocatalytic and cytotoxic effects. Surface plasmon resonance confirmed the formation of DSAgNPs with a maximum absorbance (λmax) of 420 nm. SEM and TEM images revealed DSAgNPs were spherical and rod shaped, with a size range of 20 nm and 75 nm. The zeta potential was found to be −15.41 mV. XRD and EDX analyses confirmed the nature and presence of Ag and AgCl. DSAgNPs showed considerable antibacterial activity, exhibited better cytotoxicity against brine shrimp, and shown better photocatalytic activity against methylene blue. Based on the present research work, it can be concluded that DSAgNPs could be used in the field of water treatment, pharmaceuticals, biomedicine, biosensor and nanotechnology in near future. [ABSTRACT FROM AUTHOR]