Streptomyces thermolilacinus-mediated synthesis of Selenium Nanoparticles as biocompatible anti-inflammatory agent; characterization, radiolabeling, in vitro and in vivo evaluations.

The biosynthesis of selenium nanoparticles (SeNPs) using Actinomycetes Streptomyces thermolilacinus IMA7 offers an environmentally friendly method for production without traditional manufacturing processes. These SeNPs demonstrate reduced toxicity and enhanced biocompatibility, making them ideal for biomedical applications. The synthesis was characterized through multiple analytical techniques, including UV, XRD, TEM, EDX, zeta potential, DLS, and FTIR. DLS results indicated varied particle sizes between 50.75 nm and 396.1 nm, with a predominant size around 91.28 nm, and TEM imaging confirmed an average particle size of 70.53 nm with a uniform spherical shape. FTIR and EDX analyses validated nanoparticle synthesis, while UV spectroscopy identified a peak at 282 nm. The SeNPs exhibited high stability, indicated by a zeta potential of -35.5 mV. In vitro antibacterial assessment against Gram-positive and Gram-negative bacteria revealed inhibition zones of 2.2667 ± 0.251 cm to 2.8 ± 0.1126 cm. Additionally, SeNPs showed potent COX-2 inhibition with an IC50 value of 2.227 ± 0.08 µg/ml, achieving an 85.5% inhibition at 100 µg/ml. Biodistribution studies in vivo, facilitated by radio labeling with radioactive 131I and intravenous injection in both normal and pre-inflamed mice, assessed the anti-inflammatory properties of SeNPs. Further in vivo studies were performed to validate some immunological, histopathological and immunohistochemical parameters. Serum levels of tumor necrosis factor-α, prostaglandin E2 and interleukin-10 were measured. Liver tissues were examined for histopathological and nuclear factor kappa B p65 immunoreactivity. Finally, SeNP treatment significantly attenuated inflammatory responses and ameliorated hepatic inflammatory alterations, supporting its potential as an anti-inflammatory nanotherapeutic agent.