Investigating the effect of particle size on the antibacterial activity of gold nanoparticles

Abstract

The increase of antibiotic- and/or multidrug-resistant bacteria has become a major global challenge. Killing of antibiotic-resistant bacteria requires a high dose of multiple, expensive drugs, which possess unfavourable side effects to the infected individuals. As a result, treatment of antibiotic resistant-bacteria is costly and more time is required to complete treatment. Therefore, novel substitutes are required to combat drug resistant infections while preventing further microbial resistance. Spherical gold Nanoparticles (sAuNPs) prepared using the citrate reduction method have been found to exert antibacterial activity against a number of gram positive and gram negative bacteria. However, there is still uncertainty regarding the role of size on the antibacterial activity of sAuNPs. The effect of exposure time on the antibacterial activity of sAuNPs is also still not well understood. In this study, it was hypothesized that AuNPs will show a size- and concentration-dependentantibacterial activity against selected gram positive (+) and gram negative (-) bacteria.