Substrate engineering to control cell behaviour

The topographic study of nano and micro-surfaces assumes considerable importance in Tissue Engineering. It allows, in fact, to obtain information on the interaction of cells with substrates that mimic the micro-architectural features of the extracellular matrix (ECM) of the native tissue of interest. In this way it is possible to develop biomaterials having biophysical (topography, mechanical properties) and biochemical (oxygen tension, surfacecoating) characteristics, which is able to replace in vitro complex biological systems. The aim of this PhD thesis is to study the influence of differently engineered substrates obtained through two well-established soft-lithographic techniques (ReplicaMolding (REM) and Micro-Contact Printing (mCP)) on the behaviour of several cell types (tenocytes, tendon-derived stem cells and bone marrow stromal cells). The REM technique was used for the fabrication of polydimethylsiloxane (PDMS) substrates with different stiffness obtained modifying the ratio between pre-polymer and curing agent (5:1 and 10:1 w/w). Cell culture has allowed to study the role of the different topographical features on cell morphology, proliferation, migration and production of collagen (type I and type III). The second technique (m;CP) was used to obtain protein (type I collagen and poly-L-lysine) patterns both on polypropylene substrates and on polycaprolactone (PCL) 3D scaffolds obtained by electrospinning. PDMS molds with different relief structures were fabricated by REM technique and used to print the protein islands. The influence of substrate topography on cell morphology, proliferation, and preservation of cell stemness was analyzed.