Spatially selective deposition of a reactive polysaccharide layer onto a patterned template

The amine-containing polysaccharide chitosan was selectively deposited onto patterned gold surfaces in response to an applied voltage. Standard microfabrication techniques were used to pattern gold onto silicon wafers, and these gold patterns served as templates for the electric field directed deposition of chitosan. Experiments conducted with a fluorescently labeled chitosan derivative demonstrated the spatially selective deposition of chitosan onto gold surfaces that were polarized to serve as negative electrodes. Studies with unlabeled chitosan demonstrated that a "templated" chitosan, deposited by voltage programming of electrodes, can subsequently react with standard amine-selective functional groups. This indicates that common coupling chemistries can be exploited to assemble a variety of compounds onto the deposited chitosan pattern. Thus, chitosan appears to be a unique interface material that can be "templated" onto patterned inorganic surfaces and is reactive for the subsequent assembly of organic and biological molecules.