Multiscale patterning for regenerative medicine

In the last decade nanotechnology has allowed to achieve important improvements in designing novel materials, by controlling their properties over the nanometer scale, and then in integrating them into devices. In the life science domain, nanotechnology are expected to play a key role in developing new diagnostic methods, loco-regional therapies and, in regenerative medicine, scaffold for artificial tissues and organs. Accurate control of cell adhesion is becoming a key issue in domain. Soft lithography and microfluidic devices offer a tool-box both to study biomolecules under highly confined environments [1] and to fabricate in an easy way topographic features with locally controlled mechanical and chemical surface properties, thus leading to a finer control of the interplay of mechanics and chemistry. The combination of unconventional fabrication technology and biomaterials allows both to realize state-of-the-art substrates with highly controlled lateral features and performances and to study the main properties of the biomolecules themselves by operating at a scale level comparable with the one crucial for their activity. An application of this technology to the control of cell fate that is becoming a key issue in regenerative medicine in the perspective of generating novel artificial tissues will be presented. Patterns of biomolecules and proteins have been fabricated, by a modified Lithographically Controlled Wetting (LCW), on the highly antifouling surface of Teflon-AF to guide the adhesion, growth and differentiation of neural cells (SHSY5Y, 1321N1, NE-4C) achieving an extremely accurate guidance [2]. A straightforward approach for the control of cell fate is based on the realization of neighboring surface features displaying opposite cell anchoring properties, the coexistence of surface regions favoring the cell adhesion with antifouling ones will provide a strong guidance for cell growth and migration. In this frame, Teflon is an interesting material, already employed in medical tools and devices (catheters, stents), is biocompatible, inert but at the same time strongly unprone to cell adhesion. Local surface topography is also known to influence the cell fate [3], thus, integrating this parameter in the substrate fabrication could increase the complexity of the signals supplied to the cells. In this perspective we have developed a novel fabrication technique, named Lithographically controlled Etching (LCE), allowing, in one step, to engrave and to functionalize the substrate surface over different length scales and with different functionalities. Our technological approach has the advantages to be an one-step procedure, without background passivation steps and chemical modifications of the substrates, suitable for controlling cell guidance. The results show a viable route for creating cell arrays or multi-layers cell architectures to be used in cell biology, pharmacological and toxicological studies and tissue engineering.