Glucose Monitoring for Diabetes Management:Making the Monitoring Painless and Bloodless

Adam Heller, McKetta Department of Chemical Engineering , University of Texas, Austin, USA





Our electrical wiring of electron-transferring enzymes by redox hydrogels at the University of Texas allowed us to transduce their turnover into electrical currents and to build sensors based on the direct transduction. We were able to build sensors that unlike previous ones did not require diffusing electron shuttles, which would have out-diffused into body fluids if the sensors were implanted in the body. After our successful testing of research prototypes of subcutaneously implanted glucose monitors built with electrically wired glucose oxidase, my son Ephraim Heller founded in 1996 with my help TheraSense, a venture aimed at improving the lives of diabetic people.

TheraSense did not have the resources to create the hoped-for continuous wired glucose oxidase based monitor. We made instead the monitoring of blood glucose painless, when we introducd in 2000 the first microcoulometric blood glucose monitoring system, FreeStyle, which required only 300 nL blood, 1/8th of the average blood volume of a mosquito meal. The painless monitoring led to world-wide use of the FreeStyle system and in 2004 Abbott Diabetes Care acquired TheraSense.

Work on continuous glucose monitoring with the wired glucose oxidase sensors was continued and in 2014 my Abbott Diabetes Care colleagues, to whom I still consult, introduced the FreeStyle Libre electrically wired glucose oxidase-based continuously monitoring system, making our hope a reality. Unlike earlier continuously glucose monitoring systems it is bloodless: it no longer requires periodic blood samples for calibrations. It consists of a dollar-coin sized skin-patch comprising the sensor and a short range transmitter, painlessly self-replaced every 14 days; and a cellphone-sized scanner-reader. When it is swiped over the skin-patch it displays the instantaneous glycemia, its trend and the glycemia of the past 8-hours.