Sensing glucose concentrations at GHz frequencies with a fully embedded Biomicro-electromechanical system (BioMEMS)

Abstract

The progressive scaling in semiconductor technology allows for advanced miniaturization of intelligent systems like implantable biosensors for low-molecular weight analytes. A most relevant application would be the monitoring of glucose in diabetic patients, since no commercial solution is available yet for the continuous and drift-free monitoring of blood sugar levels. We report on a biosensor chip that operates via the binding competition of glucose and dextran to concanavalin A. The sensor is prepared as a fully embedded micro-electromechanical system and operates at GHz frequencies. Glucose concentrations derive from the assay viscosity as determined by the deflection of a 50 nm TiN actuator beam excited by quasi-electrostatic attraction. The GHz detection scheme does not rely on the resonant oscillation of the actuator and safely operates in fluidic environments. This property favorably combines with additional characteristics-(i) measurement times of less than a second, (ii) usage of biocompatible TiN for bio-milieu exposed parts, and (iii) small volume of less than 1 mm-to qualify the sensor chip as key component in a continuous glucose monitor for the interstitial tissue.

Gallium arsenide 55Fe X-ray-photovoltaic battery

“…3 In many of these applications, nuclear microbatteries could be used to provide small amounts of power over long periods of time, and for this reason they have received considerable research attention. 4 Nuclear microbatteries work by converting nuclear energy to electrical energy and offer important characteristics such as high energy density, stability, and long life.…”

Micro-Electromechanical Affinity Sensor for the Monitoring of Glucose in Bioprocess Media

“…It has been shown by [31] that glucose concentrations c glc can be derived with 1% precision from the switching time t sw in SEL medium.…”

Technology modules from micro‐ and nano‐electronics for the life sciences

“…Mixtures with high viscosities on the order of a few 100 mPa s may be prepared by varying the size of dextran molecules, the ConA or dextran concentration . The usage of such mixtures for the determination of glucose concentrations appears of having been investigated for the first time by Schultz et al Various approaches to measure glucose by affinity assays have been tested since then, which initially relied on fluorescence detection, to later encompass impedance‐based and viscosimetric techniques …”