Green route for selenium nanoparticles synthesis using Senna spectabilis: A novel eco-friendly approach

Abstract

Selenium nanoparticles (SeNPs) were green-synthesised using fresh leaves of Senna spectabilis collected from Pookode college campus. Dried leaves were extracted in nanopure water at 60 °C for 45 minutes under continuous stirring. A 100 mM selenious acid solution was added dropwise to the extract, stirred for 3 hours and incubated in the dark for 45 hours. The resulting nanoparticles were collected by centrifugation, washed with isopropyl alcohol and water, and dried at 37 °C. UV-Vis spectroscopy revealed a broad surface plasmon resonance peak at 274 nm, confirming nanoparticle formation. FTIR analysis indicated the participation of phenols, flavonoids, proteins and polysaccharides in reduction and stabilisation. SEM showed irregular, rough-surfaced aggregates (~157 nm), while TEM revealed predominantly spherical particles with sizes ranging from 20-80 nm. SAED patterns confirmed a polycrystalline structure, and EDX analysis identified selenium (36%) as the main element, with carbon, oxygen, and trace sulphur from the leaf extract acting as capping agents. These results demonstrate that S. spectabilis leaf extract provides an effective, eco-friendly route for the synthesis of stable SeNPs, with potential applications in biomedical and environmental fields.