Artificial receptor layers for detecting chemical and biological agent mimics

Dimethyl methylphosphonate (DMMP) and Escherichia coli are mimics for chemical and biological agents, respectively. For designing robust sensor systems aiming at detecting them in real-life indoor environments, we designed artificial receptors based on bulk and surface imprinted polymers, respectively. Bulk-imprinted artificial recognition materials for DMMP yielded detection limits of 0.2 ppm in air on quartz crystal microbalance (QCM) sensor with selectivity factors of >40 towards indoor background contaminants, such as alcohols or acetic esters. The sensor layers retain their sensitivity for at least one year thus showing potential for maintenance-free long term sensing. They can be combined with pre-concentrator units to increase the overall performance of the system. Surface-imprinted polyurethanes optimized to selectively recognize E. coli showed ten times higher sensor responses on QCM than the respective non-imprinted polymers. Detection limits of these sensors turned out to be in the range of 0.1 mg/ml E. coli in aqueous solution. Different strains of this species (b and w, respectively) could be discriminated with selectivity factors of at least three thus implementing bioanalogous recognition in robust, man-made materials. (C) 2011 Elsevier B.V. All rights reserved.