Green Synthesis of Multifunctional Silver Nanoparticles Using Plectranthus amboinicus for Sensitive Detection of Triethylamine, with Potential In Vitro Antibacterial and Anticancer Activities

Abstract

Biogenic nanoparticles synthesized using medicinal plant extracts gain significant attention in the field of medicine. Current research reports about a simple, low cost, eco-friendly method to prepare silver nanoparticles (SNPs) using the leaf extract of Plectranthus amboinicus. UV-Visible spectroscopic analysis showed a surface plasmon resonance peak of synthesized SNPs at 410 nm. SNPs had an average hydrodynamic diameter of 111.5 nm with a zeta potential value of –19.4 mV. FTIR spectroscopic measurement revealed the characteristic peaks of SNPs. Electron microscopic analysis showed spherical-shaped nanoparticles. The potency of SNPs as a calorimetric biosensor was evaluated using its ability in detecting triethylamine (TEA)—a toxic organic solvent. A drastic change in color (pale yellow → dark black) was observed when an SNPs was treated with varying concentrations (0.01 to 0.3 mM) of TEA. SNPs showed antibacterial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Furthermore, the biosynthesized SNPs possessed efficient anticancer activity against B16F10 murine melanoma cells, which was evaluated using MTT, scratch wound, and live/dead cell assays. These results prove that SNPs can serve as biosensors and antibacterial and anticancer agents for industrial and biomedical applications.