Currently, glucose levels and blood core temperatures are measured by the invasive devices and methods, and no established non-invasive devices can solve this issue. We developed a sensor to measure multiple physiological parameters noninvasively, by photoacoustic technique together with advanced signal processing algorithm to further enhance reliability. Photoacoustic combines the merits of deep penetration provided by ultrasound, and high contrast provided by laser, to achieve promising measurement results. We integrated and miniaturized the whole sensor, so that it can be portable, and even wearable, targeting the diabetic and cardiovascular patients, in order to improve the quality of health care at home, and even enable close-loop treatment.
Technology Features, Specifications and Advantages
We developed a novel Photoacoustic (PA) glucose monitoring device, consisting of several advanced techniques: vibrational photoacoustic spectroscopy (VPS), novel acoustic resonator to enhance sensitivity, novel signal processing algorithm (multidimensional data fusion and ANN) to enhance accuracy and specificity. The quantized nature of the vibration of chemical bonds provides an effective way for the mapping of specific molecules within a complex tissue environment in a label-free manner. Hence, VPS forms the basis for this sensor to theoretically guarantee sensitivity and specificity based on unique optical absorption.
To address the sensitivity issue, novel super sensitive acoustic resonator is used to pick up extremely weak glucose signals among strong interfering noise signals. To achieve comparable accuracy with a single compact non-invasive device, novel hybrid photoacoustic detection (HPAD) is invented to enhance detection accuracy by 30%~50%, and enables its clinical application. Based on the methods discussed above, the pilot study on human using the PA sensor prototype was conducted on 2 normal subjects, and 8 pre-diabetic subjects, by comparing the blood glucose level (BGL) from non-invasive PA sensor and invasive commercial glucose meter. In phase I, overnight fasting and post-prandial BGLs were investigated, and in Phase II, the meal was replaced by 75g/dL glucose drink for OGTT. The results shown that the mean error achieved is < 20% [mean error = mean (pre/ref-1)] which well proves the functionality of the glucose sensor.
The proposed device is targeted at the continuous and non-invasive/minimally invasive monitoring of glucose and lipids for diabetic patients’ healthcare, which is estimated to be a $58.7 billion market by 2025, according to research and consulting firm GlobalData. Currently, finger-prick devices are used for monitoring, but they are invasive, cause pain, may result in complications such as infections, and the cumulative cost of using these strips is high. The glucose measurement devices from other medtech companies are all invasive based sensors for diabetes monitoring. Though good performance can be achieved, they are not convenient and may even be risky for patient use, not to mention for continuous monitoring. Our proposed sensor, on the other hand, will achieve unprecedented continuous and non-invasive glucose monitoring functionality.
The current gold-standard for glucose measurement are all invasive and require blood sample. The annual cost of invasive glucose monitoring strips is around S$800, excluding the device, and it is not continuous monitoring. Due to its re-usability and reduced risks, the proposed PA sensor is likely to result in a lower health care cost than conventional invasive testing devices. Its ease of use will significantly expand the popularity for clinical usage and reduce the operation costs of the physician.