The need for portable technologies that can rapidly identify biological warfare agents (BWAs) in the field remains an international priority as expressed at the 2011 Biological Weapons Convention. In recent years, the ability of surface-enhanced Raman spectroscopy (SERS) to rapidly detect various BWAs at very low concentrations has been demonstrated. However, in the specific case of Bacillus anthracis, differentiation at the species level is required since other bacilli are common in the environment, representing potential false-positive responses. To overcome this limitation, we describe the use of a peptide attached to the SERS-active metal that selectively binds Bacillus anthracis-Sterne as the target analyte. Using this approach, 109？？B. anthracis-Sterne？spores/mL produced an intense dipicolinic acid spectrum upon the addition of acetic acid, while the same concentration and treatment of B. cereus and B. subtilis did not. 1. Introduction Since the distribution of Bacillus anthracis spores through the US Postal System, there has been a persistent fear that biological warfare agents (BWAs) will be used by terrorist against our warfighters abroad and our civilians at home. The extreme lethality, speed of infection, low cost, and ability to aerosolize bioagents, such as B. anthracis, make this scenario attractive to terrorists and a serious concern. This concern was emphasized by the Secretary of State Hillary Rodham Clinton at the December 2011 Biological Weapons Convention held in Geneva, who stated “unfortunately, the ability of terrorists to develop and use these weapons is growing. Terrorist groups have made it known they want to acquire these weapons [1].” Our inability to rapidly detect BWAs was revealed during the Fall of 2001 as the nation became anxious not knowing the extent of the anthrax attack. This anxiety was largely due to the several days required to grow spores in culture to sufficient numbers for detection. It became apparent that emergency and medical responders need portable technologies that can determine what has been contaminated by BWAs and who has been infected with sufficient speed and sensitivity to minimize fatalities. Since that time, there has been considerable effort to develop such technologies, such as polymerase chain reaction (PCR) systems [2] and immunoassay kits [3, 4]. While PCR systems are capable of identifying B. anthracis spores in ca. 2 hours and have been installed in over 300 regional US Postal Offices [5], each system is limited in the number of samples that it can process, and the systems are not
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