Fabrication of size-tunable gold nanoparticles using plasmid DNA as a biomolecular reactor

Abstract

Gold nanoparticles (AuNPs) have been exploited for a wide range of potential applications, including drug delivery systems, catalysts, optical sensors and antimicrobial agents [1-5]. However, the harsh conditions employed in several synthetic approaches has forced researchers to investigate milder routes [6]. Biological macromolecules such as proteins [7], viruses [8], and plasmid DNA [9] have been shown to be successful candidates to ensure a milder pathway in the formation of AuNPs. Many of the aforementioned methodologies employing biological precursors nevertheless present other drawbacks such as lack of size tunability, broad dispersity, and poor shape control partially due to the tendency of cationic gold to disproportionate in aqueous solutions [10], as well as the difficulties in stabilizing metallic NPs. Combining plasmid DNA as a biomolecular reactor with a kinetically based approach, we have been able to stabilize and control the size of AuNPs.