A Wireless Biosensing Device

Abstract

In this work we have evaluated the feasibility of magnetostrictive materials in the realization of a wireless biosensing device. The measuring concept is composed of two major components that are the miniaturized sensor element and the external instrumentation for the electromagnetic excitation of the sensor and for receiving the bioinformation. For evaluation purposes a suitably cut piece of a magnetostrictive metal ribbon was used as the sensor's transducer element. To wirelessly excite this piece and to read its resonance frequency a novel instrumentation was designed and manufactured. This instrumentation provides means to realize the measurement with a much less expensive construction than those reported in the literature. To excite the sensor a magnetic field impulse is sent towards it. This sets the sensor to a vibration and as a vibrating magnetostrictive piece it creates a dumping magnetic field, which then can be collected with a receiver coil. The given concept was demonstrated and is presented here. The biosensing property for the sensor element can be achieved by utilizing another-environmentally responsive-material in connection with the magnetostrictive material as a coating. From the measurement point of view the interaction between a physiological environment and the coating results in a change of the resonance frequency of the sensor element that can then be detected and taken as the representative signal. The instrumentation can be used to measure for example temperature, viscosity, mechanical properties of coatings, pH of a medium, and several other physical, chemical and thus environmental and physiological parameters-wirelessly.