Photo-polymerization of monomer crystals producing thermo-responsive micropatterns to direct cell growth and cell selective harvest

Thermo-responsive micropatterned surface was fabricated by solid photopolymerization of N-isopropylacrylamide (NIPAAm) crystals, which were created by inducing the needle-like divergent growth of monomer crystal from saturated monomer solution triggered by single or multiple seed crystals. Since NIPAAm crystals might have densely packed crystalline structure and effectively suppress oxygen diffusion from the environment, semicrystalline PNIPAAm films were easily prepared under UV irradiation in air without inert atmosphere protection. Microscopic visualization of the human mesenchymal stem cells (hMSCs) cultured on the micropatterns has demonstrated the well-guided cell morphology including significant elongation of hMSCs and nucleus along with the micropatterned features.274