Dielectric MEMS affinity glucose sensors for continuous glucose monitoring   We recently have also been exploring MEMS affinity glucose sensors that exploit transduction principles alternative to viscometry. In particular, we have made proof-of-concept demonstration of a novel transduction method for continuous glucose monitoring, utilizing affinity binding-induced changes in the dielectric properties of the PAA-ran-PAAPBA solution. This method uses a pair of fixed electrodes enclosed in a microchamber and detects glucose-induced permittivity changes by capacitive measurements. As a result, moving mechanical parts as used in many affinity glucose sensors (including our MEMS viscometric sensors) can be eliminated. This can potentially allow the maximal miniaturization of the affinity glucose sensor with improved reliability. In ongoing work, we are further characterizing this approach and extending it to an implantable, wirelessly operated device.   Dielectric glucose sensor response (at 10 kHz) at varying concentrations of glucose and fructose (an unspecific analyte). The analyte is introduced into a PAAPBA polymer solution sandwiched between a pair of capacitive gold thin films. The binding with glucose changes the polymer's permittivity, which is reflected as changes in the sensor output (proportional to the imaginary part of the sensor impedance). In contrast, the device shows negligible response to fructose, suggesting glucose-specific detection. Researcher: Zhixing Zhang, Ph.D Student (Mechanical Engineering) Junyi Shang, Ph.D Student (Mechanical Engineering) Collaborators: Dr. Qian Wang, Departments of Chemistry and Biochemistry, University of South Carolina Dr. Jerome Schultz, Department of Bioengineering, University of California, Riverside Representative Publications: 1. X. Huang, S. Li, J. Schultz, Q. Wang, and Q. Lin, "A MEMS Affinity Glucose Sensor Using Permittivity Measurements," The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences (Microtas 2009), Jeju, Korea, 2009.