Controlled silica deposition on soft-lithography fabricated poly-L-lysine templates

Abstract

We describe the combination of soft-lithographic patterning and biomolecule-induced deposition to create microscale patterns of silica on a diverse array of substrates. A soft lithographic technique was used to create a sacrificial layer of the polymer poly(n-propyl methacrylate) (PPMA) on the desired substrate. Subsequently, poly-L-lysine was deposited on the substrate, after which removal of the PPMA yielded a pattern of PLL on the substrate. Exposure of the PLL template to a silicic acid solution resulted in silica deposition in the pattern spatially and geometrically controlled by the PLL. With this procedure, we have created both continuous and discontinuous silica patterns on metallic, ceramic, and polymer substrates. While morphology of the deposited silica varied between substrates, the ability to pattern silica through this templated growth was demonstrated on all investigated substrates. EDS, optical micrography, and SEM analysis verified the controlled deposition of silica on the PLL template patterns. This PLL template-mediated induction of silica formation may facilitate the incorporation of silica in new microdevices and serve as a prototype process for controlled deposition with other biomolecule-material systems.