| Summary: | 碩士 === 中原大學 === 醫學工程研究所 === 95 === Vital signs and physiological parameters are important measurements reflecting physical conditions of human body. For some chronic illnesses, periodically measuring physiological parameters is essential. However the measurement procedures can be painful and tiresome. Taking diabetes patients as an example, daily finger pricks for blood sugar monitor is a must to assure patients’ normal physical conditions. From the patient’s point of view, this is not only a physically pain but also a mentally torture. Thus, to minimize any further burdens to the patients, the blood meter designs must be user friendly, compact and accurate.
A miniaturized wireless glucose biosensor based on electrochemistry technique was developed in this course. It involves an external controller and an implant unit. They are linked by radio frequency (RF) techniques where power and signals can be transmitted wirelessly and bi-directionally. The RF settings used in this study were 820 kHz, 46.3 W (rms) and 1200 bps for carrier frequency, output power and data transmission, respectively. Through a series of bi-directional transmission studies in air, the results indicated the power received by the implant unit to assure its proper function must be no less than 76.5 mW. Yet, the distance limit was no greater than 3.2 cm; otherwise, the power obtained in the implant dropped significantly. In the sensing studies, the media used between the controller and the implant were either air or pork and was 3.0 cm apart. All measurements were recorded via the bi-directional transmission fashion. The current sensitivity of the implant sensing circuitry was able to achieve 20 nA. For the concentration of the hydrogen peroxide in 0.002 ~ 0.1 mM, the response curve was almost a perfect line with a linearity of 0.999. When the glucose concentration of 1 ~ 12 mM was applied the response curve was alike a line with a linearity of 0.997. An in-vivo study on the developed system was carried out as well. The internal unit was hermetically packed by PDMS and was then implanted in a male rat. The response current signals received wirelessly upon the injections of ascorbic acid confirmed that the system has a potential to become an implantable biosensor.
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