A sensitive refining of in vitro and in vivo toxicological behavior of green synthesized ZnO nanoparticles from the shells of Jatropha curcas for multifunctional biomaterials development.

ZnO nanoparticles (NPs) possess a wide range of biological functions in pharmaceutical and cosmetic applications due to their excellent antimicrobial, optical and UV protective properties. This study first reports the toxicological assessment of ZnO NPs green synthesized from Jatropha curcas shells for multifunctional biomedical applications. The hot water extract of J.curcas shells is utilized as a chelating agent for the reduction of zinc acetate and then, the prepared ZnO NPs are broadly characterized using X-ray spectroscopic and electron microscopic observations. The prepared ZnO NPs acquire high purity (100%) wurtzite crystal with hexagonal structure with the average particle size of 53 nm. In vitro and in vivo toxicity evaluation against human tumor cell lines and zebrafish embryos have ascertained the purpose of ZnO NPs in clinical research. Toxic effects of ZnO NPs were observed by a dose-dependent reduction of bacterial growth at ≥1   µg ml-1, by teratogenicity and genotoxicity in zebrafish embryos (from 3 to 90 µg ml-1) and by a significant nanoparticle uptake (0.5 ng µl-1) by a fish serum. In contrast, ZnO NPs fail to reduce the proliferation of human bladder tumor cells (UC6) and cell viability of A549 cells in vitro up to 500 µg ml-1. All these observations limit the unobstructed application of ZnO NPs at higher concentrations. Thus, abundantly used metal oxide nanoparticles like ZnO NPs examined in our present study in different animal models under in vitro and in vivo conditions will be the significant screening strategy to determine the nanotoxicity.