Chemical vs biological silver nanoparticles: Synthesis, characterization, properties, and in vitro applications

[Display omitted] •Che-AgNPs and Bio-AgNPs were characterized using UV–Vis, DLS, ZP, XRD, and SEM-EDX.•Che-AgNPs and Bio-AgNPs showed better activity against all the tested bacteria.•Bio-AgNPs showed cyto-compatibility compared to Che-AgNPs against MCF-10A cells.•Bio-AgNPs showed better catalytic activity against MR, MB, Rh-B, MO, and MG dyes.•Bio-AgNPs showed moderate to good recyclability potential. The rise of silver nanoparticles (AgNPs) has been exponential traversing through different synthesis approaches and spread across diverse scientific and technological fields. Past decade, the application of different biological materials or systems in the synthesis of AgNPs has generated much needed impetus to drive the AgNPs synthesis through ecofriendly and economical synthesis processes. The present study aims to compare the conventional (chemical approach) and biological synthesis approach. Here in, the as-synthesized silver nanoparticles (AgNPs) via chemical (Che-AgNPs) and biological (Bio-AgNPs) methods were characterized for their optical, physicochemical, crystalline, and elemental composition properties. Che-AgNPs and Bio-AgNPs showed a peak at 455 nm and 415 nm with average particle size of 198.73 nm and 135.19 nm, whereas surface charge was found to be −21.94 mV and –32.67 mV, respectively. Che-AgNPs have shown better zone of inhibition (ZOI) against gram- bacteria such as Escherichia coli (10.57 mm), Klebsiella pneumoniae (11.25 mm), Pseudomonas aeruginosa (15.43 mm), whereas Bio-AgNPs showed better ZOI against gram + bacteria such as Bacillus subtilis (13.31 mm), Coagulase-negative staphylococci (12.28 mm), Staphylococcus aureus (12.03 mm) at 50 µg per well concentration. Che-AgNPs showed better anticancer (IC50 value in µg/ml) potential compared to Bio-AgNPs against K562 (60.60 and 109.96), HeLa (67.26 and 129.31), A549 (48.94 and 105.38) cancer cells, whereas Bio-AgNPs showed minimum toxicity towards MCF-10A normal cells. Bio-AgNPs showed better photocatalytic activity compared to Che-AgNPs against methyl red (95 % and 70 %), methylene blue (64 % and 93 %), rhodamine-B (81 % and 96 %), methyl orange (76 % and 97 %), and malachite green (62 % and 97 %) dyes under 4, 9, 7, 4, and 9 min, respectively. Furthermore, Bio-AgNPs were studied for possible involvement of reactive species and their recyclability.