MOLECULAR ASSEMBLY OF PROTEINS AND CONJUGATED POLYMERS - TOWARD DEVELOPMENT OF BIOSENSORS

A molecular assembly in which a conjugated polymer is interfaced with a photodynamic protein is described. The conjugated polymer, functiona lized with biotin, is designed such that it can be physisorbed on or c hemically grown off a glass surface. The streptavidin-derivatized prot ein is immobilized on the biotinylated polymer matrix through the stro ng biotin-streptavidin interactions. The assembly, built on the surfac e of an optical fiber or on the inside walls of a glass capillary, for ms an integral part of a biosensor for the detection of environmental pollutants such as organophosphorus-based insecticides. The protein in the system can be replaced by any biological macromolecule of interes t. We study one specific case, the inhibition of the enzyme alkaline p hosphatase. The enzyme catalyzes a reaction producing an intermediate compound that chemiluminesces, and the chemiluminescence signal is mon itored to detect and quantify insecticides such as paraoxon and methyl parathion. Preliminary results indicate ppb level detection with resp onse time less than 1 minute. (C) 1995 John Wiley & Sons, Inc.