SSBII3

Biosensor - matrix interactions: things can only get better

Pankaj Vadgama
IRC in Biomedical Materials
Queen Mary, University of London
Mile End Road
London E1 4NS

Biosensors constitute a juxtaposition of two, somewhat, discordant technologies, one being biological systems immobilisation and, the other, physico-chemical transducer fabrication. Notwithstanding this, over the last two decades, many innovative biologically mediated transduction sequences have been formulated into biosensors. In all instances, a final common pathway to failure results, however, and this maps onto the adverse surface interactions between biomatrix and biosensor contact surfaces. Recognition of this, has led many research groups to develop membrane based protective interfaces at biosensors. Our own model systems, whilst directed towards practical, clinical, monitoring goals, have served as a basis for developing a series of polymeric membrane structures able to variously control hydrophilic/lipophilic molecule transport, reduce or dissolve surface colloid and cell deposits at biosensors, and importantly, enable the reagentless in situ operation of enzyme based electrochemical biosensors, most notably for glucose monitoring in diabetes. There is a global progress shift from purely transduction chemistry to interface and materials engineering as a key ingredient of clinically viable biosensors, and our own activity has reflected this shift.
Emphasis will be given to our own polymeric membrane constructs for enzyme based sensors (polycarbonate, PVC, cellulose acetate), but examples of how interfacing challenges have been overcome for similar systems elsewhere will also be provided. With greater attention on materials issues relating to biosensors, practical, reliable operation both in vitro (single use devices) and in vivo (continuous monitoring) now seems likely; the parallel with mainstream biomaterials is inescapable.