Laser interference pattern ablation of a carbon fiber microelectrode: biosensor signal enhancement after enzyme attachment.

Fluorescence microscopy was used to visualize the accumulated fluorescent product of the enzyme alkaline phosphatase to indicate where active covalently bound enzyme remained on the surface after application of a Nd: YAG laser interference pattern to a surface that was first globally derivatized with the covalently bound enzyme. The electrochemical kinetics of the same carbon fiber surface were examined through the electrogenerated chemiluminescence of Ru(bpy)(3)2+ to determine that electron-transfer sites were indeed segregated from the enzyme-binding sites. The enzyme-derivatized areas are determined to be separate and distinct from the areas of enhanced electron transfer.

Development of sub-micron patterned carbon electrodes for immunoassays.

Sub-micron sized domains of a carbon surface are derivatized with antibodies using biotin/avidin technology. These sites are spatially-segregated from, and directly adjacent to, electron transfer sites on the same electrode surface. The distance between these electron transfer sites and enzyme-loaded domains are kept to a minimum (e.

Electron transfer kinetics at a biotin/avidin patterned glassy carbon electrode.

Photolithographic techniques using a laser interference pattern were used to attach photobiotin to micron-sized stripes on the surface of a carbon electrode. Fluorophore-tagged avidin was attached to this spatially-patterned biotin with essentially no loss in spatial resolution. The kinetics of the glassy carbon surface were examined to see if electron transfer sites could indeed be segregated from the attachment sites of photobiotin-immobilized avidin.

Localized avidin/biotin derivatization of glassy carbon electrodes using SECM.

Different forms of the microreagent mode of SECM were used to attach biotin or make "clean" spots on micron-sized regions on the surface of a carbon electrode. In the direct-write mode, the SECM probe tip is used as an electrochemical "pen" depositing biotin in micron-sized lines on the carbon substrate as it is scanned across its surface. In the negative microreagent mode, the SECM probe tip is used as an electrochemical "eraser" cleaning of the surface attached molecules and leaving clean spots on the surface of a globally derivatized carbon surface.

Generation of biotin/avidin/enzyme nanostructures with maskless photolithography.

Micrometer-sized domains of a carbon surface are modified to allow derivatization to attach redox enzymes with biotin/avidin technology. These sites are spatially segregated from and directly adjacent to electron transfer sites on the same electrode surface. The distance between these electron transfer sites and enzyme-loaded domains must be kept to a minimum (e.