Biogenic reduction of gold salt, graphene oxide using Americana periplaneta salivary exudates and their anti-bacterial and anti-cancer activity

In this study, the synthesis of gold nanoparticles using the salivary gland (SG) of dead Americana periplaneta (Cockroach) was carried out by four different conventional methods. The optimization of formation was studied under microwave conditions. Reduced graphene oxide (rGO) and nanocomposite were also prepared using the magnetic stirring method. The reduction of nanoparticles was monitored by UV–Visible spectrometer. The Surface Plasmon Resonance (SPR) region obtained between 500–600 nm and 260–280 nm confirms the reduction of gold ions and graphene oxide (GO) respectively. The results of FTIR revealed the presence of a reducing agent in the gland to serve as capping agents in the reduction of gold and graphene oxide. XRD results revealed the existence of gold nanoparticles with an average size of 32.9 nm. FESEM analysis revealed spherical shape gold nanoparticles < 25 nm. Elemental mapping portrays the uniform spread of nanogold embedded in gland extract. The prepared nanoparticles were found to significantly inhibit S. aureus, B. subtilis, S. paratyphi and E. coli. The anti-cancer potential of prepared nanoparticles against skin cancer cell lines (A431) has been revealed through MTT assay and morphometric analysis. The results of this study suggesting the synthesized nanoparticles have the potential in anti-bacterial and anti-cancer activities.