Monitoring of the avidin–biotylinated dextran interaction on Au- and Ti/TiO2-electrode surfaces using a charge integrating device

In the present paper we report the use of a homemade electronic device (Multipulser), for monitoring interactions between biomolecules that may change the capacitance of an electrode. Multipulser can be used as a stand-alone, low-cost, yet effective alternative monitoring device instead of other well established commercial instruments. The operation of Multipulser is based on the integration of the electric charge used for the repetitive charging of the electrochemical cell capacitance after the application of a predetermined number of short-duration, low-amplitude voltage pulses (perturbation pulses). Multipulser was used to monitor the binding of biotinylated dextran on two different avidin modified electrode assemblies; one based on a thiol SAMs on gold and another based on Ti/TiO2 semiconductor. Measurements conducted in parallel with a commercial frequency response analyzer gave similar reaction patterns. Pulse polarity dependent behavior was revealed in the case of the Ti/TiO2-electrode assembly when bipolar potential perturbation modes were used with Multipulser.