The SURFE2R (surface electrogenic event reader): from fundamental research to commercial product.

The purpose of this review is to describe the development of the Surface Electrogenic Event Reader (SURFE²R) instrument, from the discovery of its fundamental underlying principle of capacitive coupling of biological membranes in the late 1970s to the present-day commercial instrument, which since 2012 has been marketed by the company Nanion Technologies. The story of the SURFE²R's development is a prime example of the transfer of a concept from fundamental research into a commercial product for the benefit of society. The capacitive coupling detection method was first recognized and used in research into the reaction mechanism of the proton pump bacteriorhodopsin from purple membrane fragments of a Halobacterium. The modern instrument now has a much wider application to research on the mechanisms of pumps and transporters in general, in the screening of drugs targeting pumps and transporters, and in quantifying drug affinity to biological membranes. The instrument is, therefore, of potential interest to researchers in both academia and the pharmaceutical industry. Because the author has worked and interacted with most, if not all, of the scientists involved in the evolution of the SURFE²R, the article also provides personal insights into the lives and careers of the leading scientists involved: Peter Läuger, Ernst Bamberg, Klaus Fendler, Thiemo Gropp and Niels Fertig.