Abstract

Noninvasive in vivo measurements of glycemia in 8 living non anesthetized mice were done using a microwave spiral sensor (MSS). The D-glucose concentration in the blood of the animals was measured in the 80–350 mg/dL concentration range using microwaves of frequencies from 4–5 GHz. Aqueous D-glucose solution with concentrations from 0 to 6% was orally injected into the mice and the change in the total glycemia was monitored in real time. In particular, two sets of measurements were done. In the lower frequency regime, using a resonance of about 4.1 GHz, for a 6% blood glucose concentration, there was a frequency shift of 48 MHz and a reflection coefficient S₁₁ change of 15 dB, while in the higher frequency regime, about 5 GHz, the frequency shift was 59 MHz with a S₁₁ change of 1.6 dB. These in vivo results show a signal-to-noise ratio (SNR) of 24 dB and a minimum detectable glucose level was determined to be 10 mg/dL. This is in contrast with in vitro measurements, using the same spiral sensor, which show 32 dB SNR and a minimum detectable glucose level of 5 mg/dL. The results show the utility and sensitivity of the MSS for noninvasive biological investigations of glycemia in living animals.

中文翻译：

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微波螺旋传感器在无创体内评估小鼠血液中的血糖。

摘要

使用微波螺旋传感器（MSS）对8只活着的未麻醉小鼠进行体内无创血糖测量。使用4-5 GHz频率的微波在80-350 mg / dL的浓度范围内测量了动物血液中的D-葡萄糖浓度。将浓度为0％至6％的D-葡萄糖水溶液口服注入小鼠体内，并实时监测总血糖的变化。特别地，进行了两组测量。在较低的频率范围内，使用大约4.1 GHz的共振，血糖浓度为6％时，频率偏移为48 MHz，反射系数S ₁₁变化为15 dB，而在较高的频率范围内，大约为5 dB GHz，使用S _11时的频移为59 MHz变化为1.6 dB。这些体内结果显示信噪比（SNR）为24 dB，最小可检测葡萄糖水平确定为10 mg / dL。这与使用相同的螺旋传感器进行的体外测量相反，该传感器显示32 dB SNR和5 mg / dL的最低可检测葡萄糖水平。结果显示了MSS在活体动物血糖无创生物学研究中的实用性和敏感性。