Essential dynamics for the convergence of microelectronics and biotechnology derives from the field of biomolecular sensing and is due to the large cost pressure in the health sector. Here, the efficient techniques enabled by microelectronics may contribute to the analytics of various human metabolites, which are of importance for the patient's health and have to be monitored regularly.
One of the critically important metabolites in the human body is glucose, which delivers the chemical energy required for practically all aspects of living. Its transport into the cells is carried out via an insulin-controlled transporter protein. In case of a deficient insulin level, as it occurs in diabetic patients, the increased glucose level in the blood may cause serious secondary health effects. It would be very desirable to dispose of a continuous glucose monitor acting as an implant in the patient in order to avoid or reduce hypo- and hyperglycamic states.
At IHP in Frankfurt/Oder we are developing a minimally invasive glucose sensor, by which diabetics may continuously control the glucose concentration . The sensor operates by the principle of affinity viscosimetry and relies on the competing binding reaction between a plant protein (concanavalin A) and a saccharide, i.e. glucose or dextran. For this purpose, a sensoric liquid containing ConA and dextran is filled into a cavity and interacts via a semi-permeable membrane with the interstitial tissue. The variation of glucose concentration in the latter causes a variation of the sensoric fluid’s viscosity, which is detected by a flexible cantilever within the cavity; a schematics of the sensor principle is shown in the figure. By virtue of modern microelectronic [56, 58] and microsystem technology  the sensor unit may be miniaturized to a volume of only a few cubic millimeters and may thus be applied to a human body over durations of a few days.
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