Tin oxide nanoparticles (SnO₂-NPs) synthesis using Galaxaura elongata and its anti-microbial and cytotoxicity study: a greenery approach

The progression of green nanoscience towards greater heights and new standards is obvious due to the non-toxic methods of synthesis and other added advantages. With this background, this research focused to prepare stable tin oxide nanoparticles (SnO₂-NPs) mediated by the ethanolic extract of Galaxaura elongata (red algae). The biosynthesized nanoparticles were subjected to analyses by Scanning (SEM) and Transmission Electron Microscopes (TEM), X-ray diffraction (XRD), UV–visible (UV–vis) and energy dispersive X-ray spectroscopies (EDS). The outcomes as indicated by characterization tools demonstrate that Galaxaura elongata extract reduced SnCl₂ into SnO₂-NPs within 60–90 min at room temperature. The nanocrystallite structures were 35 nm in size. Related to the applications at the nanoscale, the antibacterial activity was investigated against Bacillus subtilis, Staphyloccous aureus, Pseudomonas aeruginosa and Escherichia coli. The zone of inhibition did range between 16 and 24 mm for the NPs. Galaxaura elongata extract showed a moderate MIC value of 0.31–9.47 µg/ml on the tested organisms, while the MIC values of tin oxide nanoparticles are 15.6 µg/ml and 62.5 µg/ml. The SnO₂-NPs were cytotoxic on A549 human lung carcinoma cells with an IC₅₀ value of 28.08 μg/ml. The results of the study indicate that the NPs were effective antibacterial and cytotoxic agents.