Biological activities of chitosan-salicylaldehyde schiff base assisted silver nanoparticles
Salman S. Alharthi, T. Gomathi, J. John Joseph, J. Rakshavi, J. Annie Kamala Florence, Prasad N. Sudha, Govindasamy Rajakumar, Muthu Thiruvengadam
Abstract
The nanobiotechnology era has sparked interest in the green synthesis of stable silver nanoparticles (Ag-NPs) without hazardous chemicals. As a result, the current study used chitosan-salicylaldehyde Schiff base (CSB) as a non-toxic, reducing and stabilizing agent to prepare stable silver nanoparticles. The characterization of Ag-NPs impregnated chitosan-salicylaldehyde Schiff base was fulfilled using UV-Vis, FTIR, XRD and TEM studies. The absorption band present around 425 nm in UV-Vis spectra indicated the formation of Ag-NPs. The appearance of a new band for the CN bond, deduction in the intensity of the CO group of salicylaldehyde and NH group of chitosan confirmed the formation of Schiff base and Ag-NPs in FTIR analysis. XRD pattern revealed the orientation and crystalline nature of Ag-NPs with 2θ at 38°, 46° and 54° related to Ag-NPs (JCPDS No. 04-0783), whereas the peak at 2θ = 27° associated with CSB. The total porosity of 53.24% was determined using the liquid displacement method. The CSB-Ag-NPs have good scavenging activity (46.25% and 49.35% activity in DPPH assay and H2O2 assay), great antibacterial (zone of inhibition 17 mm and 19 mm for E-Coli and Pseudomonas sp.), antifungal (18 mm for P. notatum), and anti-larvicidal activity, according to biological assessments. The synthesised Ag-NPs were non-toxic to marine ecosystems in a safety bioassay test.