Explorations towards the production of novel biogenic nanomaterial using Rhodococcus aetherivorans BCP1

Abstract

Nanoparticles are typically synthesized through a variety of physical and chemical methods that have been refined over years of research. However, they can come with a high cost in terms of equipment and chemicals needed, as well as the toxicity of the chemicals used. Recently the use of living organisms as a bionanofactory to produce nanomaterial has emerged as an intriguing idea. Bacteria have evolved over time to handle metal toxicity primarily through reducing metal ions, which can be exploited to produce nanomaterial. Rhodococcus aetherivorans BCP1 is one such bacterium that has been found to display strong metal tolerance and shown the ability to convert toxic metals into a variety of nanomaterials. Thus, exploration was done to further test BCP1’s ability to produce nanomaterials with other metals. Cadmium selenide quantum dots are a type of nanomaterial that is highly sought after. These materials find a variety of uses in electronics and bioimaging, and scaled production of these materials is strongly needed. BCP1 was used to explore the production of CdSe QD from these highly toxic metals, and the particles were characterized to explore their properties. Absorbance peaks at 290 and 500nm were seen amongst all samples however, fluorescence was only observed from one and not characteristic of CdSe QD in literature. Samples displayed large sizes of >100nm which far surpassed the expected range (2 – 10nm) for CdSe QD. BCP1 exposure to Na2SeO3 and CdCl2 results in the production of nanomaterial, however the identity appears to be closer to selenium nanoparticles rather than CdSe QD. Silver nanomaterial is one of the most used nanomaterials, with applications found in modern consumer goods. Since the properties of silver nanoparticles are highly dependent on their size and shape, BCP1 was used to explore the production of size and shape tunable silver nanoparticles. Spherical and cubic silver nanoparticles were produced that displayed absorbance peaks at 290nm and 550-600nm and FRET induced fluorescence was observed at 360nm. 2µm cubic material was also spotted with longer AgNO3 exposure. The particles showed uncharacteristically weak antimicrobial activity against gram positive and negative organisms.