జర్నల్ ఆఫ్ ఎనలిటికల్ & బయోఅనలిటికల్ టెక్నిక్స్

నైరూప్య

Species Selective Measurement of 10 B. anthracis-Sterne Spores within 10 Minutes by Surface-Enhanced Raman Spectroscopy

Chetan Shende, Hermes Huang, Jay Sperry and Stuart Farquharson

The use of biological warfare agents by terrorists remains a global concern. While there has been substantial effort since the 2001 distribution of Bacillus anthracis spores through the US Postal System to develop analyzers to detect this and other biological agents, the analyzers lack sensitivity, lack specificity (produce high false-positive rates), are too slow, or cannot be fielded. For the past decade we have been investigating the ability of Surface Enhanced Raman spectroscopy (SERS) to overcome these limitations. Recently, we developed an assay by functionalizing silver nanoparticles with various peptides to selectively bind B. anthracis, and then adding acetic acid and silver colloids to release and detect, respectively, dipicolinic acid as a biomarker by SERS. Here we describe the successful measurement of B. anthracis-Sterne spores with a 10- to 20-fold selectivity over other Bacillus species at 105 spores/mL, using the peptide functionalized SERS assay with a sensitivity capable of detecting 10 spores in a 103 spores/mL sample in 6.5 minutes. This measurement represents 6 orders-of-magnitude improvement over our previous peptide based SERS assay measurements.