Sub-microfabrication of protein micropatterns for cell biology applications

We successfully demonstrated the realization of fabricating protein sub-micro patterns for cell biology applications. To successfully generate the protein sub-micro patterns, some new designed procedures were involved into the DUV photolithography with micro contact printing process, such as TEOS film, RIE etching and AR3 coating. For the flexible aspect ratio requirements, TEOS film was added as a hard mask between photoresist and substrate for increasing the etching selectivity. According to our experimental results, the aspect ratio could be offered from 1.5 to 4.5 by RIE recipe tuning. When the pattern size is into sub-micro level, the sticking issue between silicon and PDMS will be getting worse. Besides, it also has very strong dependence with pattern sizes, pitches and shapes. We analyze the chemical mechanisms and select suitable material to be the buffer layer to avoid the crosslinking from these two materials. The AR3 layer was employed to be a buffer layer and successfully reduce the issue of pattern sticking. After that, we observed the neuron and cell outgrowth in these special designed protein sub-micro patterns. The investigated patterning process that combining with DUV photolithography and micro contact printing could be used to generate functional surfaces for cell biology applications