Application of Natural RNA Regulators to Tune Biosynthesis of Nanoparticles for Enhanced Material and Functional Properties

The biosynthesis of metal nanoparticles by bacteria has emerged as a promising environmentally-friendly alternative to traditional chemical synthesis. However, this technology remains limited by the lack of knowledge regarding metal reduction and nanoparticle biosynthesis mechanisms within various bacteria, hampering the ability to control nanoparticle properties necessary for various applications. Since biosynthesis is commonly viewed as a stress response mechanism, initiated to detoxify toxic metal ions present in the environment, we investigated the role that RNA regulators such as small RNAs (sRNAs) may play in nanoparticle synthesis and functionality. This study was performed in the context of Deinococcus radiodurans, where we created deletion strains of selected sRNAs and find that some of these RNA regulators significantly affect the yield of biosynthetic silver nanoparticles (AgNPs), indicating their importance in nanoparticle biosynthesis. We also demonstrate that modulating the levels of these sRNAs can improve the catalytic and antimicrobial activity of the resulting AgNPs relative to AgNPs synthesized using the wild-type strain. Since functionality is often dictated by the properties of the AgNPs, further materials characterization of the AgNPs reveals drastic changes in the surface chemistry and overall composition of the AgNPs upon deletion of specific sRNAs. Taken together, our results demonstrate how modulating sRNA levels enables the biosynthesis of AgNPs with unique material properties and improved functionality. As such, we introduce sRNAs as a new platform for engineering the biosynthesis of metal nanoparticles using bacteria.