Studying biological adhesion using optical tweezers

Summary form only given. Adherence phenomena are responsible for a variety of transport processes in biological systems. Understanding adhesion is important in the areas of immune responses, migration and accumulation of cells at inflammatory sites, and it can also be useful in the development of drug delivery systems. In many cases adherence is mediated by interactions between specific molecules and occurs via weak, non covalent bonds due to polar, hydrogen or van der Waals interactions. The strengths of these bonds fall into the range accessible with optical forces found in optical tweezers. By employing a setup that consists of two optical tweezers we can manipulate two objects simultaneously, and bring together or pull apart cells or microspheres coated with specific biomolecules. We can thus investigate the dynamics of adhesion as well as its inhibition.