Monitoring “Real-Time” Biological Binding Events on a Microelectrode Array

Abstract

Because microelectrode arrays contain collections of spatially isolated electrodes that can each be individually addressed, they provide an intriguing platform for monitoring the activity of small molecules, peptides, and proteins. The arrays are utilized by placing the members of a molecular library on the surface of the array above the electrodes such that each unique member of the library is located on top of a unique electrode or a set of electrodes in the library. In this way, the binding activity on the molecular library and the electrochemical reactions happen on the electrodes are coupled. The binding events between the molecules on the surface of the array and molecules in solution can thus be monitored with the change of behavior of the electrochemical reactions on the electrodes. The overall strategy is illustrated in Figure below.We are expanding the types of experiments that can be employed to examine enzyme-peptide binding with the use of microelectrode array. We have previously shown RGD-peptide/ integrin, v-107/ VEGF, and R6A - Gαi1 interactions can be monitored on an array. While success of the synthetic chemistry can be ensured by fluorescence labeling, the binding can be monitored by cyclic voltammogram.Now, our focus has moved from distinguishing specific binding/non-specific binding/no binding to distinguishing different types of specific binding events. We are working to employ those electrochemical methods in conjunction with the traditional FRET studies in order to provide unique insights into the mechanism of peptide cleavage reactions. In so doing, we hope to add new capabilities to existing surface analytical methods. Figure 1