Synthesis, Characterisation, and Antimicrobial Efficacy of Acid Fuchsin Schiff Base-Modified Silver Nanoparticles

In the current work, silver nanoparticles (AgNPs) were green synthesized using starch and modified with anionic dye (acid fuchsin) and aldehyde (salicylaldehyde and cinnamaldehyde). Thus in situ formation of Schiff base stabilized AgNPs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis. The size and the stability of the Schiff base modified AgNPs were explored using DLS and Zeta potential analysis. TEM analyses showed the size of the Schiff base (cinnamaldehyde) modified AgNPs with an average particle size of 5–10 nm. The synthesized Schiff base modified AgNPs were tested for their antibacterial efficacy against gram-negative bacteria such as Escherichia coli (MTCC733), Pseudomonas aeruginosa (MTCC1688) and gram-positive bacteria such as Bacillus subtilis (MTCC41) and Enterococcus faecalis (MTCC96). The antifungal activity of the synthesized materials has been studied against C andida albicans along with standard fluconazole. Higher antibacterial and antifungal activities were observed for the Schiff base (SB) capped AgNPs due to the combined effect of SB and AgNPs. The mechanism of the bactericidal activity of nanoparticles is suggested as due to the interaction of AgNPs with the cell membrane. The results of the present study confirm that SB stabilized AgNPs have significant potential as an antimicrobial agent in treating infectious diseases.