Chitosan-mediated synthesis of biogenic silver nanoparticles (AgNPs), nanoparticle characterisation and in vitro assessment of anticancer activity in human hepatocellular carcinoma HepG2 cells

The biopolymer chitosan is currently in widespread use because of its nontoxicity, biocompatibility and biodegradability. Therefore, in this study, chitosan extracted from shrimp shells was used to synthesise biogenic silver nanoparticles (AgNPs). UV–visible spectrophotometry of reduced silver nanoparticles in the colloidal solution showed a single peak at 400 nm, confirming the formation of AgNPs. The presence of biomolecules responsible for reducing and capping the biogenic AgNPs was confirmed by FTIR. Surface morphology of the biosynthesised AgNPs was characterised using SEM, and TEM analysis showed the formation of spherical shapes 17–50 nm. The presence of elemental silver in the synthesised biogenic AgNPs was confirmed using EDX and the crystalline structure characterised by XRD. Cytotoxicity of biogenic AgNPs was determined using MTT and the trypan blue exclusion assay. Morphological changes in HepG2 cells were detected by analysis of the DNA ladder pattern via gel electrophoresis, and the IC50 of HepG2 cell inhibition by AgNPs was 48 μg/ml. The upregulated caspase 3 and 9 protein expression results confirmed cell death via apoptosis. In conclusion, chitosan has the ability to synthesise AgNPs with in vitro apoptotic activities.