**1. Introduction**

This Chapter deals with bulk hydrogels consisting of a widely used biomaterial: poly(ethylene) glycol (PEG). PEG is renown for its bio-inertness; it is very effective in suppressing non-specific protein adsorption (NSPA) and thereby preventing cell adhesion. However, we have observed unexpected adhesion of fibroblast cells to the surface of bulk PEG hydrogels when the surface was decorated with micrometer-sized, topographic patterns. This Chapter describes the aim of our investigations to unravel the biophysical, biochemical and biomechanical reasons why these cells do adhere to the intrinsically antiadhesive PEG material when it is topographically patterned.
