Whole-cell biosensors based on permeable filter-like growth substrates (first image on the right) provide the option to expose the cell layer from both sides to some compound of interest. When cells are grown in these materials even the lower, substrate-facing plasma membran domain is accessible. Systems like this have been used for many years in so-called Ussing chambers to study the physiology of barrier-forming epithelial and endothelial tissues.
A recent prototype development from our lab (second image on the right) has provided an automated, multi-well device to perform Ussing-chamber like impedance measurements of epithelial and endothelial tissues to quantify the cell layers' barrier function towards ion movement. The physical parameter that is measured is called the transepithelial electrical resistance (TER) and often used to describe the electrical tightness of 2D tissues. In 2008 it has been introduced into the market and the project was awarded with the Transferpreis der Universität Münster as well as the Innovationspreis des Münsterlandes.
We are currently exploring several strategies to make use of these kind of porous polymer materials (lower image on the right) equipped with different transducer functionalities on either side of the filter for novel whole-cell biosensors.