Bactericidal activity of starch-encapsulated gold nanoparticles

Abstract

We report the bactericidal applications of ecofriendly starch encapsulated gold nanoparticles (St- AuNPs). The mechanism of interaction of the properly characterized St-AuNPs with both Gram negative and Gram positive bacteria were investigated using spread plate assay, transmission electron microscopy (TEM), and fluorescent propidium iodide (PI) exclusion assay. The St- AuNPs were found to possess significant dose dependent antibacterial activity against both types of bacteria. St- AuNPs at 1.2 mg/mL caused 98 % eradication of Gram positive bacteria that was exposed over a period of 12 h. Similarly, 4.8 mg/mL St-AuNPs caused 98 % eradication of Gram negative bacteria over a period of 12h. The St- AuNPs are biocompatible and present a useful solid porous carbohydrate-based polymer vehicle with excellent antimicrobial activity against both Gram negative and positive bacteria.