Book Description
Patterned polymer brushes are used in biological applications to enhance cell function and to achieve selective cell growth. These patterned surfaces have a variety of applications, including cell sheet harvesting and tissue engineering. This work describes creation of chemical, topological, and responsive patterns on glass by sequential surface-initiated polymerization of poly(N-isopropylacrylamide)-co-(2-hydroxyethyl methacrylate) (pNIPAM-co-HEMA) and subsequent use of UV lithography to pattern the surface with pNIPAM. The cell adhesion peptide, RGD, is then immobilized on the surface of the copolymer pHEMA via DSC-coupling to spatially enhance cell adhesion properties. By culturing cells at 37 degrees celsius, cells selectively grow on DSC-activated pNIPAM-co-HEMA and not on the block copolymer pNIPAM due to its non-fouling properties at thicknesses greater than 20nm. Selective cell growth of NIH3T3, a mouse embryonic fibroblast cell line, is demonstrated on pNIPAM-co-HEMA/pNIPAM patterns of different dimensions. By lowering cell culture temperatures below the lower critical solution temperature (LCST) we can take advantage of the functionality of pHEMA's hydroxyl group and the thermoresponsive property of pNIPAM in order to detach patterned cell sheets detach from pNIPAM-co-HEMA surface. Thus, we have created a single polymer brush platform that provides both positive and negative tone patterns for cell growth, as well as incorporating thermoresponsive polymers to fine tune surface properties and enable selective detachment of cell sheets, as well as facile modification of non-fouling regions via common and robust DSC-coupling for use in cell sheet engineering applications.
