Our group at the Max Bergmann Center of Biomaterials (Leibniz Institute of Polymer Research part) focuses research at the interface of living cells and their local microenvironment with a special focus on biopolymer matrices. We use the design of polymer interfaces and biopolymer matrices to understand and control the behaviour of cells in terms of adhesion, proliferation, and differentiation. These tasks involve the modulation of protein-materials interaction on the molecular level as well as dynamic reorganisation processes and mechanical behaviour of cells on the micrometer scale. In the talk I want to touch three projects where I see potentials in getting theoretical modelling involved in a better understanding of protein-materials interaction in cell adhesion, the biophysical description of cell adhesion and the mechanics of whole cells, and the assembly of supramolecular biopolymer matrices and their mechanics. In the first topic a fine-tuned physicochemistry of polymer surfaces is used to control the interaction strength of proteins which act as ligands of adherent cells. The variation of the anchorage strength of the proteins to the substrate allows us to control the dynamics of their reorganisation by active cell processes as well as the forces imparted by the cells to the substrate. In a simple Monte Carlo simulation approach we already tried to model parts of this complex mechanisms occurring at the substrate-cell interface on a molecular level. The second topic is also linked to the control of cell adhesion by substrate anchorage. However, it focuses on the micrometer scale behaviour of cells and their mechanics. The modulation of adhesion forces of cells by ligand-substrate interaction as well as laterally constraining cell shape by micrometer scale patterns allow us to modulate the pattern of main intracellular mechanical elements, the actin cytoskeleton. Possible regulation mechanisms might be found in diffusion-related phenomena or mechanical equilibrium conditions like the well-known tensegrity model. Furthermore, a finite-element approach suggests cell membrane tension or curvature as a trigger for characteristics changes of the actin cytoskeleton pattern. As a third topic I will present data on the molecular self-assembly of supramolecular biopolymer fibrils consisting of collagen I and heparin. Our data suggest the highly charged glycosaminoglycan heparin to be stoichiometrically intercalated in the fibrillar collagen structures and possibly acting as a intermolecular crosslinker, a process which is not found in vivo. This assembly strategy reveals structures with a distinctively different shape and mechanics, which might have possible applications as functional biomaterials scaffolds. We could gather a quite detailed knowledge on the overall supramolecular arrangement of the collagen molecules. However, the possible localisation of heparin inside the supramolecular structure is not known. Possible gap regions in the collagen organisation, originating from an enzyme treatment during collagen preparation, are thought as possible harbours. We would be interested to model this supramolecular arrangement comparing it with our structural and mechanical data. A possible expansion of this supramolecular assembly strategy might involve other functional molecules and their intercalation in this highly periodic pattern for a possible construction of naturally derived conducting elements.