HYBRID BIOSENSOR FOR SIMULTANEOUS ELECTROCHEMICAL AND THERMOMETRIC DETECTION

XIE B TANG XJ WOLLENBERGER U JOHANSSON G GORTON L SCHELLER F DANIELSSON B

B. Xie et al., HYBRID BIOSENSOR FOR SIMULTANEOUS ELECTROCHEMICAL AND THERMOMETRIC DETECTION, Analytical letters, 30(12), 1997, pp. 2141-2158

25

INGLESE

Article

Chemistry Analytical

Analytical letters → ACNP

0003-2719

30

12

1997

2141 - 2158

ISI

0003-2719(1997)30:12<2141:HBFSEA>2.0.ZU;2-1

Simultaneous detection of multiple signals for common biochemical/elec trochemical reactions is a challenging area of research for comparativ e studies. Based on our previous work with electrochemically assisted thermal biosensors, a hybrid biosensor has been developed for the simu ltaneous monitoring of the electrochemically generated current and the thermal signal produced in association with enzymatic catalysis. The sensor combined the two measurement principles of electrochemical rege neration of substrate and flow injection biocalorimetry. The enzyme co lumn was constructed of a platinum foil in electrical contact with a p oly (pyrrole)-coated reticulated vitreous carbon (RVC) matrix onto whi ch tyrosinase was immobilized. The column functioned as enzyme reactor , working electrode and thermally sensitive element together with the thermistors. Catechol was oxidized by tyrosinase to form 1,2-benzoquin one which was subsequently regenerated electrochemically on the electr ode surface. The primary heat production developed by the enzyme react ion could be measured calorimetrically. At the same time, the electroc hemical reduction of 1,2-benzoquinone generated a current that was det ected by the working electrode (enzyme column). Preliminary results sh owed good correlation of the two signals at both high and low oxygen c oncentrations in the buffer. A linear range between 12.5 and 250 mu M catechol was obtained for the enzyme reaction. The sensitivity of the thermal measurement system was significantly enhanced by the recycling of catechol. The hybrid sensor provides a useful tool for comparative studies.