Effect of Moringa oleifera Protein-Coated Gold Nanoparticles as Naturally Derived Disruptors of Biofilms

Microbes having affinity to metallic surfaces develop a highly structured and sessile colony known as biofilms which poses significant challenges to the domain of implant surgery. Biofilm-mediated infections and the associated burden have prompted the search for multipronged approaches to tackle the problem. Gram-positive pathogens, most notably Staphylococcus aureus, has been known to colonize human tracts and form biofilms on implants and prosthetic devices. Antibiotic tolerance, drug efflux, and recalcitrance to the host immune response have added to the existing predicament of the biofilm infections.

The search for inexpensive but effective avenues for combating biofilms has led to the use of metal nanoparticles conjugated with plant-derived proteins.

In this study, a protein from Moringa oleifera leaf extract, p62, which has been previously identified to have antibiofilm properties, was conjugated with spherical gold nanoparticles (AuNPs) to target S. aureus biofilm formation.

The adsorption of p62 on the AuNPs was confirmed through microscopy, and the kinetics of binding was determined by plasmon resonance. The p62 coated AuNPs remained stable in solution and caused the successful disintegration of mature biofilms, more efficiently than the protein alone. The p62-AuNPs were also found to disrupt the morphology of the cocci and cause cell death as evidenced from the live/dead cell imaging through confocal microscopy. The protein and the nanoparticle were not cytotoxic to C2C12 human myoblast cell lines, affirming their suitability to be used on implants.