Development of a Separation and Detection System for Bacillus anthracis Spores Based on Peptide Conjugates Identified from Peptide Library

Abstract

A simple, specific and rapid identification system against Bacillus anthracis spores was developed using specific capture peptides conjugated with a bead-based biosensor, which was tightly and specifically bound onto the spore surface of B. anthracis. We successfully detected and separated B. anthracis spores from the spores of B. thuringiensis and B. cereus using this peptide-magnetic bead conjugates by fluorescence and anthrax-specific analyses. For more convenient mediation of high-throughput detection against B. anthracis spores, streptavidin-biotin interactions of spore-peptide and spore-peptide-magnetic bead conjugates were performed, and we demonstrated the separation and detection of B. anthracis spores using this method. In the presence of mixed condition of several types of Bacillus spores, the B. anthracis spores were easily separated using the oligopeptide-conjugated magnetic beads, thus allowing the clear detection of B. anthracis spores from B. cereus, B. subtilis, and B. thuringiensis spores. This oligopeptidebased strategy was rapidly and unambiguously identified as little as one viable B. anthracis spore in less than 1 h with a simple binding assay format. When assessed for its effectiveness for specifically and selectively detection of environmental spores phylogenetically similar to B. anthracis spores, such as B. thuringiensis and B. cereus spores, the system was free of false-positive signals.