Microfabrication and characterization of cellon-chip platforms on poly (amidoamine) hydrogels

The control of cell growth, proliferation and differentiation on biomaterials surfaces is of fundamental importance for regenerative medicine, prosthetics, or cell-based assays. The microfabrication of cell-on-chip platforms based on a new family of poly (amidoamine) hydrogels, are promising for in vitro and in vivo applications. Hydrogels present characteristics that mimics biological environments, such as the cross-linked nature of the extracellular matrix, the tissue properties (high water content), and the permeability to oxygen and metabolites. Hydrogels based on poly (amidoamine) results in an optically transparent, biocompatible and fully biodegradable substrate recommended for body implants that are minimally invasive, and naturally eliminated by human body. In my PhD work I intended to use microfabricated hydrogels for fine-tuning the contact guidance of cells. As microfabrication tools I set up reaction injection moulding for producing features down to 100 µm and developed a novel approach relying on electron beam lithography. This innovating microfabrication consists in the ability of directly writing patterns on already cross-linked hydrogels, with the capability of producing structures at sub-micrometric scale. The exposure to the electron beam produces particular modifications enabling the control of physico-chemical properties of irradiated area. I obtained a selective attachment of proteins as a function of the electron-beam dose; an exclusive adhesion and growth of neural cells on the exposed surfaces; and the control of neurite outgrowth guidance along a microfabricated network. These results offer new perspectives to build physiological microenvironments or cell-on-chip platforms, based on a novel class of microfabricated hydrogels.