Block Copolymer Brushes for Completely Decoupled Control of Determinants of Cell-Surface Interactions

The known determinants for cell-surface interactions, comprising biochemical cues, patterns, passivating functionality, and control of tether mechanical properties, are fully decoupled in tailored block copolymer brushes synthesized by surface-initiated atom transfer radical polymerization. Exploiting sequential polymerization of a passivating underlying polyacrylamide (PAAm) block with defined cross-linking followed by a second poly(acrylic acid) block, which can be conjugated with a selective adhesion peptide, hierarchically structured brushes that can be micro-patterned by soft lithography were obtained. The interaction of NIH 3T3 fibroblasts and PaTu 8988t pancreatic tumor cells with brushes that differed only in the stiffness of the hidden PAAm block or only in the peptide ligand, while keeping all other parameters constant, revealing profound differences in cell adhesion and morphology. In particular, cells could only attach well to stiff RGD presenting brushes.