Probing of bioaffinity interactions at interfaces using impedance spectroscopy and chronopotentiometry

Faradaic impedance spectroscopy and chronopotentiometry are used as electro chemical methods for probing in situ bioaffinity interactions on surfaces b etween enzymes and their molecular or macromolecular cofactors. Alcohol deh ydrogenase (E.C. 1.1.1.1.) and lactate dehydrogenase (E.C. 1.1.1.27) bind t o an NAD(+)-functionalized monolayer electrode with association constants c orresponding to 1.6 x 10(4) and 1.5 x 10(5) M-1, respectively. Cytochrome o xidase binds to an oriented cytochrome c monolayer assembled on an An elect rode with an association constant of K-a= 1.2 x 10(7) M-1. (C) 2000 Elsevie r Science S.A. All rights reserved.