Selective, Specific, and Versatile Personal Biosensors to Organophosphate Chemical Toxins Composed of Polyurethane Immobilized Enzymes

Organophosphorus (OP) nerve agents are a serious threat to military and civilian personnel, so rapid detection of OP compounds in all of these forms is of paramount importance to prevent casualties. Recently, we combined porous polyurethane foam formed in situ from water-miscible hydrophilic urethane prepolymers and enzymes such as ChEs. One of the advantages of this technique imparted to the immobilized enzymes is resistance to denaturing events. Most important, the enzyme will not leach from the polyurethane support so the ChE-badge can now be used to sample for OPs in diverse environments such as soil and large bodies of water, as well as conventional sources such as air. In addition, immobilized enzyme badges are being designed with a unique attribute not present in the current nonimmobilized detectors: a rapid field system to identifying which OP is present. For instance, organophosphorus hydrolase (OPH) hydrolyzes sarin more readily than soman, while laccase hydrolyzes the VX agent preferentially over the G agent OPs. Currently, we are evaluating polyurethane immobilized laccase for long-term stability and kinetic properties of VX hydrolysis. Thus, the immobilized sensor can provide new features and testing of more diverse environments than the M256A1 and M272 kits combined. Also, the ability to identify the OP toxin in real-time using the immobilized differential detector would aid in treatment and securing the contaminated area, in the identification of the use of OPs, and permitting first responders to identify the OP present in a civilian terrorist act.