Effect of Gold Nanoparticle Size on Bacterial Cell Attachment and Initial Biofilm Formation

Abstract

The purpose of this study was to evaluate the effect of the size of gold nanoparticles (AuNPs) on Streptococcus mutans (S. mutans) cell attachment and initial biofilm formation. Three different sizes of polyvinyl-pyrrolidone coated AuNPs (5, 10, or 20 nm) were used in this study. The ability of AuNPs to adhere to bacterial cells and the inhibition of biofilm formation were studied through a transmission electron microscope (TEM) based morphological examination and a biofilm formation assay, respectively. Only the 5 nm AuNPs caused a slight inhibition of S. mutans biofilm growth. The 5 nm size AuNPs easily adhered to the bacterial cell surface as observed through TEM; however, the adhesion of 10 nm and 20 nm particles to bacterial cells was low. It is hypothesized that the attachment of AuNPs to S. mutans disrupts the initial biofilm formation.