Wet and dry chemistry kits for total creatine kinase activity using a microfabricated, planar, small-volume, amperometric cell

A novel microfabricated amperometric microcell is used for total creatine k inase (CK) activity determination. The microcell employs a photolithograpic ally prepared flat form electrode pair for detection. The enzyme-catalyzed reaction takes place in a thin Liquid film, supported by a replaceable poro us, hydrophillic membrane, resting on the working electrode surface. Simple , two electrode, amperometry was used, to avoid overvoltage shocks caused b y "open" circuits. An electrochemically prepared size-exclusion membrane wa s utilized on the working electrode to provide selectivity for the amperome tric detection of hydrogen peroxide. Two different analytical reaction sequ ences following the CK catalyzed creatine phosphate hydrolysis were investi gated. Both result in hydrogen peroxide production. The rate of hydrogen pe roxide production is proportional to the total CK activity, and it is follo wed after the dispensation of sample into the microcell. The slope of the a mperometric current-time curve is evaluated as the analytical signal. (C) 1 998 Elsevier Science B.V. All rights reserved.