AVS 52nd International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI1-ThM

Paper BI1-ThM6
Electrochemical Programming of Bioactive Surfaces

Thursday, November 3, 2005, 10:00 am, Room 311

Session: BioMEMS and Microfluidics
Presenter: B.C. Bunker, Sandia National Laboratories
Authors: B.C. Bunker, Sandia National Laboratories
M. Farrow, Sandia National Laboratories
K.R. Zavadil, Sandia National Laboratories
W.G. Yelton, Sandia National Laboratories
Correspondent: Click to Email
Self-assembled monolayers containing cyclodextrin have been used as a template for the reversible electrochemical patterning of surfaces. Electrochemical patterning occurs as a result of the oxidation and reduction of functionalized ferrocene in solution. When Fe(II) is present in the ferrocene, this neutral aromatic species is adsorbed by the cyclodextrin surface. When Fe(II) is oxidized to Fe(III), the ferrocene desorbs from the cyclodextrin. The electrochemically switchable surface is of interest in microfluidic systems when the ferrocene is functionalized to interact with specific biological species. We have succeeded in attaching biotin to the ferrocene via an ethylene glycol linkage. The biotinylated ferrocene can be made to adsorb and desorb from cyclodextrin deposited on gold electrodes. We have demonstrated that the biotin on the ferrocene is active toward the adsorption of streptavidin. With programmable streptavidin surfaces, we can create patterns with a wide range of biological species (i.e. any species that can be biotinylated). The synthesis, characterization, and electrochemical switching of the films are described, involving techniques such as cyclic voltammetry, electrochemical stripping, secondary ion mass spectroscopy, ellipsometry, and the quartz crystal microbalance. Use of the switchable films for creating programmable patterns of antibodies in sensors is described.