Early, Non-Invasive Sensing of Sustained Hyperglycemia in Mice Using Millimeter-Wave Spectroscopy

Abstract

Diabetes is a very complex condition affecting millions of people around the world. Its occurrence, always accompanied by sustained hyperglycemia, leads to many medical complications that can be greatly mitigated when the disease is treated in its earliest stage. In this paper, a novel sensing approach for the early non-invasive detection and monitoring of sustained hyperglycemia is presented. The sensing principle is based on millimeter-wave transmission spectroscopy through the skin and subsequent statistical analysis of the amplitude data. A classifier based on functional principal components for sustained hyperglycemia prediction was validated on a sample of twelve mice, correctly classifying the condition in diabetic mice. Using the same classifier, sixteen mice with drug-induced diabetes were studied for two weeks. The proposed sensing approach was capable of assessing the glycemic states at different stages of induced diabetes, providing a clear transition from normoglycemia to hyperglycemia typically associated with diabetes. This is believed to be the first presentation of such evolution studies using non-invasive sensing. The results obtained indicate that gradual glycemic changes associated with diabetes can be accurately detected by non-invasively sensing the metabolism using a millimeter-wave spectral sensor, with an observed temporal resolution of around four days. This unprecedented detection speed and its non-invasive character could open new opportunities for the continuous control and monitoring of diabetics and the evaluation of response to treatments (including new therapies), enabling a much more appropriate control of the condition.

Non-Invasive Glucose Sensing Technologies and Products: A Comprehensive Review for Researchers and Clinicians

“…The advantages of using mmW or MW sensing techniques is that they are highly sensitive with a fast response in real-time, are flexible, consume low power, are easy to manufacture, are robust, small in size, portable, and cost-effective, and measurements can be taken without precise alignment [99][100][101]. Spectral mmW occur between 30 and 300 GHz (or 1 and 10 mm), where, in particular, a W-band spectrometer (75-110 GHz) in the mmW spectrum has been shown to be an effective technique for in vivo glucose monitoring through skin tissue [102][103][104]. However, it is important to note that mmW and MW are not safe for continuous glucose monitoring, as repeat exposure could cause damage to the tissue due to their penetration depth [25].…”