Anticancer potential of zinc oxide nanoparticles against cervical carcinoma cells synthesized via biogenic route using aqueous extract of Gracilaria edulis

Development of novel approach for cancer therapy, sparing healthy normal cells overcoming the limitation of available therapies is of prime importance for cervical cancer treatment. Recently metal oxide based chemotherapeutics has emanated as a promising approach for cancer therapy. Hence, the present study was carried out to assess the anticancer potential of zinc oxide nanoparticles (ZnONPs) synthesized using biogenic source, aqueous extract of Gracilaria edulis. The prepared ZnONPs were characterized using UV-Visible spectroscopy, FTIR, XRD, FESEM, EDX and HRTEM. The anticancer potential of ZnONPs against cervical cancer cell lines (SiHa cells) was evaluated using MTT and the mechanism of apoptosis was evaluated using various staining techniques. UV-Vis spectroscopy exhibited absorption band at 367 nm specific for ZnONPs and the average energy gap was calculated as 3.37 eV. Further characterization by XRD, TEM, and FESEM illustrated the formation of wurtzite structure (hexagonal phase) with size ranging between 20 and 50 nm. EDS of SEM analysis confirmed the presence of Zn and O, which was further substantiated by XPS analysis. PL emission studies showed UV emission peak at 387 nm and broad visible emission peak at 520 nm. Zeta potential value of -28.2 mV depicted the stability of ZnONPs in the dispersion medium. Results of anticancer potential illustrated that ZnONPs exhibited cytotoxic effect against SiHa cells in a dose dependent manner with IC50 value of 35 +/- 0.03 mu g/ml. AO/EtBr dual staining, JC-1 staining, Hoechst 33258 nuclear staining and comet assay illustrated the ZnONPs induced ROS mediated mitochondrial dependent apoptotic cell death in SiHa cells. Further, flow cytometric analysis using Annexin V/FITC dye demonstrated that ZnONP5 induced both apoptotic and necrotic mediated death in SiHa cells. Over all the results conclude that ZnONPs synthesized using algal sources might act as a new medicinal approach for the treatment of cervical carcinoma in conjugation with the current therapy.