Far-from-equilibrium phenomena in bioadhesion processes

This review is concerned with the physical chemistry of processes occurring during bioadhesion i.e. when living cells approach and contact other cells or when living cells approach and contact nonliving or solid surfaces. A good deal is known at present about biological membrane composition pointing towards a heterogeneous composition of this medium. There is now a clear need to detailed specific and quantitative understanding of interactions between biological membranes. Experiments and theory begin to converge in order to provide a better understanding of the cell functions depending on these interactions: anchorage spreading locomotion differentiation activation of immune response and so on. In this review equilibrium processes are first recalled and interpreted by several models (mechanical or thermodynamical models). Far-from-equilibrium processes are then described for mammalian cells or more precisely for red blood cells. These processes are interpreted in terms of the interfacial instability theory taking into account the role of external contraints leading to dissipative structures. Examples of such far-from-equilibrium processes are the appearance of nonuniform morphologies due to the bridging of surface polymers the clustering of surface receptors following a surface reaction between cell receptors and fixed binding sites on a substrate etc. The approach remains always macroscopic but opens vistas to correlate with molecular approaches. Several important and challenging research directions regarding non-equilibrium processes in bioadhesion are the relation between adhesion and fusion the metabolic regulation controlled or induced by adhesion the process of reversible/irreversible adhesion and separation etc. The importance of integrated studies combining the efforts of different disciplines (biology chemistry physics computer science etc.) is stressed throughout this review and will provide new answers to fundamental problems. © 1996 by John Wiley & Sons Ltd.SCOPUS: ar.j