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

Abstract

An affinity-viscometry-based micro-sensor probe for continuous glucose monitoring was investigated with respect to its suitability for bioprocesses. The sensor operates with glucose and dextran competing as binding partner for concanavalin A, while the viscosity of the assay scales with glucose concentration. Changes in viscosity are determined with a micro-electromechanical system (MEMS) in the measurement cavity of the sensor probe. The study aimed to elucidate the interactions between the assay and a typical phosphate buffered bacterial cultivation medium. It turned out that contact with the medium resulted in a significant long-lasting drift of the assay’s viscosity at zero glucose concentration. Adding glucose to the medium lowers the drift by a factor of eight. The cglc values measured off-line with the glucose sensor for monitoring of a bacterial cultivation were similar to the measurements with an enzymatic assay with a difference of less than ±0.15 g·L−1. We propose that lectin agglomeration, the electro-viscous effect, and constitutional changes of concanavalin A due to exchanges of the incorporated metal ions may account for the observed viscosity increase. The study has demonstrated the potential of the MEMS sensor to determine sensitive viscosity changes within very small sample volumes, which could be of interest for various biotechnological applications.

Prolonged Corrosion Stability of a Microchip Sensor Implant during In Vivo Exposure

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Functionalization of Oxide‐Free Silicon Surfaces for Biosensing Applications

“…Example of frequently applied strategies in biosensing includes to measure the quasi-static deflection caused by biomolecules binding to the surface of a cantilever, or a mass induced change in resonance frequency of a piezoelectric material such as in surface acoustic wave sensors or quartz crystal microbalance sensors. [144][145][146][147] Kanyong et al [148] studied the electrografting of a diazonium salt bearing a maleimide functionality carried out on both Aucoated quartz crystals as well as Au-quartz crystals that had been additionally coated with 110 nm of microcrystalline Si by plasma enhanced chemical vapor deposition. Combining electrochemical quartz crystal microbalance with an IR ellipsometric method allowed in situ monitoring of the adsorption process and confirmed a dense monolayer.…”

The on-Line Monitoring Analysis of Electromechanical Equipment Under Embedded Sensor

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