Grass-mediated biogenic synthesis of silver nanoparticles and their drug delivery evaluation: A biocompatible anti-cancer therapy

Abstract Biologically inspired green synthesis of nanoparticles has become a promising alternative against the chemically fabricated process considering reduced toxicity. This is the first report of using annual meadow grass (Poa annua), in the green synthesis of silver nanoparticles (AgNPs). Phytochemical analysis and gas chromatography - mass spectroscopy of P. annua extract depicted ample quantities of reducing and stabilizing agents for AgNPs including flavonoids, phenols, and alkaloids. The synthesized AgNPs (36.66 ± 7.85 nm in diameter) were found to be stable in different solvents (deionized water, phosphate-buffered saline, dimethyl sulfoxide) for over one month at 4 °C. These biogenic AgNPs have been further loaded with an anti-cancer drug (Euphorbia dracunculoides Lam. plant extract) and coated with starch as a novel drug delivery composite (AgNPs-EDL@Starch) for cancer therapeutics. HR-TEM and FE-SEM analysis confirmed the spherical morphology of synthesized AgNPs coated with biomolecules and their homogenous dispersion. The biocompatibility and anti-cancer effect of AgNPs and AgNPs-EDL@Starch were proved using antioxidant assay (61.42 ± 0.04% and 81.00 ± 0.12%), hemolysis assay (8.9% and 3.8%), and MTT assay against SCC7 cell lines (≈60% and ≈40%), respectively. In an in vivo study, the AgNPs with the highest dose (300 mg/kg) exhibited no significant cytotoxicity after 7 d of oral administration to Sprague Dawley rats (n = 3). The biological functionality and biocompatibility of a common agriculture waste based AgNPs, suggest their promising role as a potential drug carrier in the field of therapeutics.