Hand-held device detects chemical and biological warfare agents

Abstract

Since the 9/11 attacks, chemical and biological warfare (CBW) agents now represent an imminent threat, with drinking-water supplies considered particularly vulnerable. This is because water distribution systems present many opportunities for deliberate contamination: in water reservoirs, at various production andstorage points, and during delivery to consumers. To counter this threat, the US Army Joint Service Agent Water Monitor (JSAWM) program has been tasked with developing hand-held assays (HHAs). These devices are based on lateral flow immunoassay technology that can detect CBW agents and incorporate software to analyze receiver operating characteristics (ROC) for the assessment of the CBW threat level. HHA tickets have been developed (see Figure 1) that can be read either by human eyes or by an optical scanner. However, only the latter can provide quantitative measurements. Currently-used HHA scanners were initially developed for medical applications. But they are very expensive (approximately $30,000) and not suitable for analytical purposes. The accurate determination of the sensitivity of HHAs also requires ROC curves that need to be analyzed. To address these issues, a new method using commercial flatbed optical scanners is being investigated for HHA data collection and new 3D ROC curves are also being developed for data analysis. An initial demonstration using a $100 flatbed scanner significantly outperformed a $30,000 medical scanner in reading HHAs with more-accurate quantitative CBW information. However, new scanning and image-processing software is required to fully utilize this inexpensive flatbed technology. Development efforts are presently focused on the three key components required for the successful implementation of HHA in CBW detection. The Figure 1. A hand-held assay ticket can quickly identify selected chemical and biological warefare (CBW) agents. (Image courtesy of ANP Inc.)