Spectral and Electrical Nanoparticle-Based Molecular Detection of Bacillus Anthracis Using Copolymer Mass Amplification

Nanoparticle-based detection of microorganisms has gained attention in recent years because of the need for rapid detection in multiple readout formats for clinical, food safety, and defense applications. The 2001 anthrax attacks are one example, where rapid detection would have aided in cleanup and containment efforts, and significantly reduced economic costs. Current detection methods, such as antibody recognition, polymerase chain reaction, and bio-barcode assays (BCA) are limited by shelf life, cost, complexity, or detection times. BCAs are very sensitive, but once the amplified single-stranded (ssDNA) output is obtained, up to four additional hours of readout time are required. Previously, BCA detection was used to identify the pagA gene from Bacillus anthracis. In this paper, we describe a modification of the BCA reporter ssDNA for rapid readout. Two ssDNA molecules were designed to copolymerize, and then, continually hybridize into double-stranded DNA (dsDNA). The dsDNA was then detected using Pico Green dye, an intercalating fluorescent dye. Additionally, a semimetallic nanoparticle was conjugated to SYBR 101 dye for electrical reduction/oxidation readout. Copolymerization and dye detection provide rapid readout of ssDNA from BCA with potential for multiplexed detection through electrical readout.