Community Research and Development Information Service - CORDIS

Multi-analyte sensor arrays suited to mass production

Devices for the measurement of oxygen, pH, carbon dioxide, glucose, lactate, glutamine and glutamate are already in a mature state. A nonlinear optically transduced pH sensor for microphysiometry and immunosensor application is being investigated. The first generation device has a resolution of 0.001 pH units. The glucose, lactate, glutamine, glutamate and lactose devices are based on the electrochemical detection of enzymatically produced hydrogen peroxide. The enzymes are physically entrapped in hydrogel membranes covering a modified thin film platinum electrode. The key technology developed is a thin film process for the formation of miniaturized hydrogel membranes. In gas and ion sensors, these hydrogel membranes serve as electrolyte compartments. In biosensors, they serve as a matrix for the entrapment of enzymes and as well as a diffusion barrier. The hydrogels consist basically of poly(HEMA) and they are prepared by crosslinking a liquid precursor solution under ultraviolet irradiation. Performing this irradiation on a mask aligner allows microfabrication of such membranes. Sensors comprising multiple closely spaced enzyme membranes can be realized without cross-contamination of enzymatic precursor is a gentle method of immobilization, the immobilized enzymes showing dramatically increased stability. The enzyme membrane precursors can be applied to the substrate comprising the electrodes either by a spinon process or by simply dispensing it. Depending on the desired application different technologies for the fabrication of the transducing electrode arrangement are applied. Devices intended for in vivo application should be small and flexible in order to avoid excessive tissue damage. Therefore a highly flexible polymeric base material onto which an electrode arrangement is deposited using thin film technology was employed. This transducer comprises the necessary counter and reference electrodes in addition to 2 working electrodes and is typically configured as an integrated glucose/lactate sensing device. Many medical monitoring applications require sensing elements incorporated in an extracorporeal flow through arrangement. A microfluidic liquid handling part with an integrated sensor array was developed. A thin or thick film electrode arrangement was used comprising 1 reference electrode and 4 individually configurable working electrodes and printed circuit board comprising a counter electrode, drilled holes for inlet and outlet of analyte, and a photo-patterned seal. These 2 parts are assembled to give a 4 parameter (eg glucose/lactate/glutamine/glutamate array) flow through device with an internal volume of 1 ul.

Reported by

Albert-Ludwig-University Freiburg
Am Flugplatz
79085 Freiburg
Germany
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