Biomimetic polymer brushes containing tethered acetylcholine analogs for protein and hippocampal neuronal cell patterning

This paper describes a method to control neuronal cell adhesion and differentiation with both chemical and topographic cues by using a spatially defined polymer brush pattern. First, biomimetic methacrylate polymer brushes containing tethered neurotransmitter acetylcholine functionalities in the form of dimethylaminoethyl methacrylate or free hydroxyl-terminated poly(ethylene glycol) units were prepared using the "grown from" method through surface-initiated atom transfer radical polymerization reactions. The surface properties of the resulting brushes were thoroughly characterized with various techniques and hippocampal neuronal cell culture on the brush surfaces exhibit cell viability and differentiation comparable to, or even better than, those on commonly used poly-l-lysine coated glass coverslips. The polymer brushes were then patterned via UV photolithography techniques to provide specially designed surface features with different sizes (varying from 2 to 200 μm) and orientations (horizontal and vertical). Protein absorption experiments and hippocampal neuronal cell culture tests on the brush patterns showed that both protein and neurons can adhere to the patterns and therefore be guided by such patterns. These results also demonstrate that, because of their unique chemical composition and well-defined nature, the developed polymer brushes may find many potential applications in cell-material interactions studies and neural tissue engineering.