Hot embossing of pyramidal micro-structures in PMMA for cell culture

For the investigation of the effect of 3-dimensional structures upon cell attachment and growth, polymeric micropyramids with dimensions comparable to the size of cells were fabricated. Moulds for the hot embossing of the polymers were manufactured in silicon by photolithography and wet chemical etching. For an accurate casting the moulds need very smooth surfaces, which were achieved by using KOH/IPA for crystallographic etching. A PTFE-like layer was deposited by a RIE process from C4F8 plasma to form an anti-sticking layer on the mould surfaces to result in an easy release of the embossed substrates. Preparation methods and embossing parameters were established and optimised to emboss pyramidal structures with different base lengths and distances from 1 mu m to 40 mu m into PMMA. The imprinted polymeric microstructures were characterised with profilometry and SEM. First cell culture experiments were performed using neuronal and epithelial cell types on the micropyramidal surfaces to investigate their influence upon the cell-surface interactions. While both cell types attached nicely on either plane or microstructured PMMA surfaces, especially the neurite outgrowth was influenced by the pyramidal structures. The effect of the pyramidal design upon cell development might be of potential interest for the use in cell culture and tissue engineering. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.