Abstract
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 (SnO
2
-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 SnCl
2
into SnO
2
-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 SnO
2
-NPs were cytotoxic on A549 human lung carcinoma cells with an IC
50
value of 28.08 μg/ml. The results of the study indicate that the NPs were effective antibacterial and cytotoxic agents.