Eco-friendly Synthesis of Selenium Nanoparticles Using Orthosiphon stamineus Leaf Extract and Its Biocompatibility Studies

Green synthesized nanoparticles possess potential bioactivity with low toxicity and enhanced bioavailability and could be used for various biomedical applications. Orthosiphon stamineus is a medicinal plant with a rich bioactive compound that could be used for nanoparticle synthesis. In the current study, we synthesized selenium nanoparticles (SeNPs) using an aqueous extract of Orthosiphon stamineus (OS) leaves and evaluated their biocompatibility. The prepared SeNPs were characterized using a UV–visible spectrophotometer, Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDAX). The biocompatibility of the SeNPs was investigated using hemocompatibility and apoptosis assay. Our findings displayed a colour change from dark green to ruby red, which in turn confirmed the formation of SeNPs. The UV–visible spectrum further confirmed this, showing maximum absorbance at 266 nm. The FTIR peaks in the fingerprint regions confirmed the capping of the extract containing flavonoids and phenolic compounds over the SeNPs. The particle size analysis of SeNPs revealed a size range of 30–120 nm, and the zeta potential was found to be − 6.32 mV. The XRD data confirmed the crystalline nature of SeNPs, and its crystallite size was calculated as 29.40 nm. Analysis of surface morphology using SEM showed oval-shaped particles with an average particle size of 80 nm, as evidenced by particle size results. The SeNPs formation was further confirmed by EDAX results. Hemocompatibility studies showed less than 5% lysis at a higher concentration of 100 µg/mL. Peripheral blood mononuclear cells treated with 100 µg/mL of biosynthesized SeNPs showed cell viability similar to that of untreated cells. Hence, we conclude that eco-friendly SeNPs could be used as potential candidates in various biomedical applications, including therapeutics and diagnostics.