Title: Surface Chemistry of Biological Systems
Description: This volume of Advances in Experimental Medicine and Biology is based on an American Chemical Society Symposium entitled: "Surface Chemistry of Biological Systems", which took place in New York on September 11-12, 1969. Thanks to the special photo offset process used by the publishers, the papers are appearing very soon after their presentation, and at a lower cost than usual. These advantages are appreciated by the scientific community. As the title of the volume indicates we have attempted to bring the scientific approach and techniques of surface chemistry to the complex problems of biological systems. Two previous symposia in this field have been published, one in the Journal of Colloid and Interface Science (24:1-127, 1967) and the other in the Journal of General Physiology (52:187S-252S, 1968).

The previous publication outlets, a chemical and a biological journal, help to emphasize the interdisciplinary nature of the material and also the appropriateness of the choice of Advances in Experimental Medicine and Biology for the current symposium. Surface chemistry continues to be useful and productive in the direct study of biological systems, and also indirectly as a context for the consideration of biological problems. There has been considerable progress in the last few years, and this volume is composed of research contributions by leading workers on a variety of problems in this general area. Along with the recent results of research on specific problems, each paper includes an up-to-date survey of the general field highlighting those areas in which there has been considerable activity in the last few years, and also indicating some of the directions in which future research will continue.

The papers can be grouped into three categories: 1- The first group deals with model systems, such as monolayers bilayers and dispersions, where the emphasis is on interactions between the substances themselves and also between the substances and other materials in bulk phases. These papers are directed primarily at the problems of membrane stability, and in particular the role of lipids. 2- The second group deals with the composition of the surfaces of natural systems and the various interactions that can result between the surfaces. These papers consider such problems as the chemical composition of a simple membrane, the substances present at the outer surfaces of various cells, the lung surfactant system, etc. 3- The third group deals with various aspects of transport across surfaces and the factors that influence transport. These papers emphasize the specialized mechanisms that are characteristic of transport across natural membranes, e.g.

gastric secretion, pinocytosis in ameba, sugar transport in red blood cells. In the case of sugar transport it is of some interest to note that some components of the red cell which are believed to be "carriers" of sugars in membranes can be shown to act as carriers in a simple interfacial system. There is some overlap between the groups, which is to be expected in an active field, but the groupings help one to see the trends in the general areas. For example, work is continuing on the composition and surface structure of membranes and there is a growing interest in the study of interactions in and between surfaces. There is also renewed awareness of the changes that occur in natural surfaces with time and as a result of the processes under study. This latter factor is particularly important in the study of transport processes where one must now begin to consider that membranes may change (in degree of hydration, charge, etc.) during a process and that average properties, e.g.

permeability constants, may prove to be inadequate. Finally, one must note the advances that are being made in the study of medical problems, such as the characterization and the mechanism of deposition of lipids in atheromatous plaques, the development of compatible materials for intravascular prostheses, the characterization of the lung surfactant system, etc.
Subjects: Biological Transport, Surfaces, Propriété des, Membranes, Congrès, Congresses, Transport biologique, Surface Properties, Membranes (Biology)