LOCALIZED AVIDIN BIOTIN DERIVATIZATION OF GLASSY-CARBON ELECTRODES USING SECM/

Different forms of the microreagent mode of SECM were used to attach b iotin or make ''clean'' spots on micron-sized regions on the surface o f a carbon electrode. In the direct-write mode, the SECM probe tip is used as an electrochemical ''pen'' depositing biotin in micron-sized l ines on the carbon substrate as it is scanned across its surface. In t he negative microreagent mode, the SECM probe tip is used as an electr ochemical ''eraser'' cleaning off the surface attached molecules and l eaving clean spots on the surface of a globally derivatized carbon sur face. This type of simple micromodification of the surface of a carbon electrode will allow the fabrication of biosensors that can potential ly be tailor-made for a variety of applications.