Green Synthesis of Sulphur Nanoparticles Using Azadirachta indica (Neem Leaf) and Its Characterization

Nanoscience has found various applications in different biomedical fields. The synthesis of nanoparticles (NPs) has become a vast area of research due to its potential applications. These particles can be prepared by different chemical, physical and biological approaches. In recent years, green synthesis of NPs using plant extracts has gained much interest due to non-toxicity and very low cost of synthesis. The plant extracts act both as reducing or stabilizing agent as well as capping agent. Neem (Azadirachta indica A. Juss) is a well-known medicinal plant and has been studied for the biosynthesis of NPs. A. indica has various phytochemicals identified that can reduce the metal ions. The bio reduction of NPs from neem extract is an eco-friendly, low cost and green synthesis method. These NPs are reported to exhibit good antimicrobial, mainly antibacterial activity. NPs was characterized by Dynamic Light Scattering (DLS) for particle size, particle size distribution, poly- dispersity index, zeta potential, UV visible spectrophotometer and Fourier-Transform Infrared Spectroscopy (FT-IR) for functional characteristics. Dynamic light scattering measurements for particle size (nm) and Polydispersity Index showed that the particle size was in the range of 35-40 nm with Polydispersity Index of 0.280-0.290, it is the mid-range value and indicating that the particles were in disperse form in aqueous suspension. From the analysis, the zeta potential value was found to be (-5.77 mV), revealing the better stability of synthesized sulphur nanoparticles in aqueous suspension. The FT-IR spectrum showed characteristic absorption of wavenumber from 3384.73 cm-1 and 533.56 cm-1. The absorption spectra of UV-visible spectrophotometer in between the range of 200-800 nm.