CHEMILUMINESCENCE BIOSENSORS USING TRIS(2,2'-BIPYRIDYL)RUTHENIUM(II) AND DEHYDROGENASES IMMOBILIZED IN CATION-EXCHANGE POLYMERS

Tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)) and dehydrogenase e nzymes are immobilized in cation exchange polymer films to create elec trogenerated chemiluminescence (ECL) biosensors. Eastman AQ and Nafion polymers were used as immobilization support in a regenerable ECL sen sor for NADK and NADPH and in biosensors for glucose, lactate and etha nol. The biosensor design places an enzyme-loaded polymer film adjacen t to a Ru(bpy)(3)(2+)- loaded polymer film covering a platinum electro de. The modified electrode was used in a flow injection analysis syste m as an ECL detector. The CL response to samples containing enzyme sub strate and cofactor (NAD(+)) result from the Ru(bpy)(3)(3+) ECL reacti on with NADH produced by the enzyme. The analytical response to NADH u sing an AQ film modified with Ru(bpy)(3)(2+) was similar to that seen for Nafion films modified with Ru(bpy)(3)(2+). The coimmobilization of Ru(bpy)(3)(2+) and dehydrogenase enzymes in the same film showed redu ced enzyme activity which led to various biosensor designs with adjace nt layers. The ECL biosensor concept was shown applicable for both NAD (+)-and NADP(+)-dependent enzymes, where NADPH detection ranged from 0 .01 to 100 mu M NADPH. (C) 1997 Published by Elsevier Science Limited.