Assembly and characterization of biofunctional GABA-immobilized surfaces

Here we report progress toward the development of bioactive surfaces based on GABA, a major neurotransmitter in the nervous system. While immobilization techniques have focused largely on antibodies, enzymes, and receptors, to our knowledge, this is the first report of a prototype neurotransmitter-immobilized surface. Biosurfaces were assembled onto either mica or glass using passive adsorption of avidin and subsequent attachment of a derivatized form of GABA via a biotin-avidin affinity bond. Surface characterization was carried out using atomic force microscopy to visualize surface topology. The data reveal 1) passive adsorption of avidin is uniformly dispersed and cluster densities can be controlled through the concentration of the avidin incubation solution; and 2) GABA tethered via biotin to these avidin surfaces showed a homogenous distribution of the tethered neurotransmitter molecule onto glass and two different population distributions onto mica. Functional assays performed to test the biological activity of the synthesized GABA, direct sandwich ELISA, as well as comparison of AFM images of anti-GABA antibody incubation of these prepared GABA surfaces to control studies using anti-IgG antibody, together support the idea that these synthesized surfaces are biofunctional.