Special attention is directed to the use of biodegradable materials used in regenerative medicine, including tissue engineering. An important aspect of degradation is the issue of the fate of the degradation products and particles. Degradation kinetics and mechanisms are studied in both in vitro and in vivo models. Macrophages are the prime cellular candidates to remove particulate debris from the tissues. Therefore, in vitro models involving stimulation/activation of macrophages by degradation products may give insight in processes occurring in the body. Moreover, these models can have a strong potential to predict the behavior of newly designed, degradable polymers in vivo. Furthermore, functional implantation studies are carried out using rat and rabbit models.
Fundamental interactions between cells and materials are studied at the level of adhesion and cell cycle with cell biological methods, in relation to the physico-chemical properties of the biomaterial surface. These properties are determined in terms of chemical composition, wettability and roughness and can be modified using different coating methods, wet chemistry (e.g. covalently-coupled silanes), or glow discharge treatments. Biocompatibility of biomaterials relates to the absence of adverse cellular reactions and modulation of cell adhesion and subsequent responses. Most currently developed materials need to evoke cell adhesion and spreading, while potentially displaying differential cell function. Adhesion is being studied in a controlled fashion, using adhesion-supporting and -inhibiting substrata. The explorations of the cell biological basis of differential behavior will give more detailed answers on rules governing cell–material interactions.