Biosynthesis of gold nanoparticles by the extremophile bacterium Deinococcus radiodurans and an evaluation of its application in drug delivery

Recent advancements in cancer drug delivery have various drawbacks. To address these constraints, a new paradigm for the creation of AuNPs from microorganisms is being explored due to its cost-effectiveness, mass production capability, and substantial environmental impact. Herein, we described a facile method for biosynthesis of AuNPs employing the radiation-resistant extremophile bacterium Deinococcus radiodurans culture filtrate (cell free supernatant) as a reducing agent and capping agent in an aqueous solution without any external energy. The synthesis of AuNPs was inferred by the color change from pale red to purple that was supported by various characterization tools. The UV–visible spectrum has an absorption peak at 542 nm, which highlights the excitation and Surface Plasmon resonance of AuNPs. The FT-IR was used to examine the functionalization of the biosynthesized AuNPs. The FESEM image of AuNPs are spherical in shape and range in size from 30 to 50 nm and the AuNPs was functionalized with Polyvinylpyrrolidone and further conjugated with the targeting vehicle folate for the delivery of Quercetin. The drug release of Quercetin shows 90 % at 22 hours. Functionalized AuNPs demonstrated dose-dependent cytotoxicity in this investigation against the human breast cancer MCF-7 cell line. Furthermore, the study of apoptotic induction using the AO/EB staining approach demonstrates the obvious morphological alterations brought on by induced apoptosis. Based on the administration of Quercetin, DNA damage has been shown by DNA fragmentation analysis. AuNPs from the culture filtrate of bacterium Deinococcus radiodurans are being actively synthesized and functionalized for a targeted anticancer drug delivery system in the current work.