1. Could you explain the significance of your article to the non-specialist?

There is no doubt that proteins are of tremendous importance not only in biology, but also in field as e.g. modern food technology, biotechnology, or health care. In practically all applications proteins are dissolved in water and come close to solid surfaces. Often we wish that these surfaces repel the protein and thus prevent its adsorption ("fouling"). In biotechnology, on the other hand, we wish to immobilize an enzyme to use it repeatedly as a catalyst. So we need to fixate the enzyme on a surface without impeding its activity. This is the starting point of the present paper: How can we understand the interaction of proteins in aqueous solution with solid surfaces to which polymers have been attached? 

 

2. What has motivated you to conduct this work?

We discovered some time ago that proteins are adsorbed on surfaces to which a dense layer of polyelectrolyte chains has been grafted. Such layers termed "polyelectrolyte brush" have been the subject of intense research in recent years. Our idea was that these polyelectrolyte brushes would strongly repel proteins in aqueous solution. Much to our surprise, we found the contrary - proteins are strongly attracted by such layers if the ionic strength is low! The first publication of this finding was done in PCCP in 2003 (5, 1671) and research on this "polyelectrolyte-mediated protein adsorption" has become a rapidly progressing field in the meantime. 

 

3. Where do you this work developing in the feature? 

We are just at the beginning of an emerging field. At this moment, we hope to improve our theoretical understanding of this effect. Work based on the ideas presented in our paper is under way. Moreover, we believe that the interaction of proteins with free polyelectrolytes and with polyelectrolyte brushes is of direct importance in biological systems. So we hope to see more work directed to biochemical problems in the near future.

 

4. Are their any particular challenges facing future research in this area?

Bringing together physical chemists and biochemists to work on this problem! We need to explore possible implications of the polyelectrolyte-mediated protein adsorption in biochemistry as e.g. in specific recognition or for interaction of proteins with surfaces in cells and extracellular surfaces. Another challenge is certainly given by possible uses of this effect in biotechnology. The question is: Can we use this effect to immobilize enzymes in a simple but efficient way without impeding their activity? We hope that our review will induce colleagues from quite different fields to look into these highly interesting problems!