Arthur Usmani

Non-Aqueous Polymeric Systems (NAPS) for Diagnostic Applications

Water-borne enzymatic coating based dry chemistries have been used for more than 20 years, especially by diabetics, for self-monitoring of blood glucose. Until recently it has been believed that enzymes work only in water and not organic solvents. Synthesis of a hydroxylated acrylic polymer and the novel concept of dispersing enzymes have enabled us to design non-aqueous coatings. These coating-films gave excellent dose response and dynamic range because of their ability to be ranged by antioxidants. The color signals were independent of the reaction time and the chemistry was thermally stable. Molecular forces and thermodynamical considerations have been used to explain the performance of such dry chemistries.

Moldable Dry Chemistry

Results of thermal analyses of select diagnostic enzymes and their utility in determining stability of dry chemistries have been presented in this paper. An enzymatic compound consisting of glucose oxidase, peroxidase, tetramethyl benzidine indicator, alkylbenzene sulfonate and polyhydroxyethyl methacrylate was prepared and compression molded. Strips molded up to 150°C gave good glucose response. During molding the redox centers of the enzyme are not disturbed whereas the bulk of the enzyme, polymeric in composition, blends with PHEMA producing the unusual stability. There is a distinct possibility that a reaction injection molding (RIM) composition and processing can be developed for making dry chemistries.