Raman devices show promise for blood glucose testing

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Advances in Raman spectroscopy could one day make invasive blood glucose tests a thing of the past

A non-invasive spectroscopic device for monitoring blood glucose levels has been found to be just as effective as invasive techniques by an evaluative study conducted by researchers from the University of Missouri School of Medicine and the Massachusetts Institute of Technology (MIT). The results were recently published online by Analytical and Bioanalytical Chemistry.

Diabetics usually test blood glucose by pricking a finger, but this could soon be unnecessary thanks to a new device developed at MIT. The Raman spectrometer is able to measure the chemical composition of skin and determine blood glucose levels without pricking a finger to collect a blood sample.

‘With diabetes on the rise, the development of an accurate, efficient and inexpensive alternative method to test blood glucose levels is an urgent clinical need,’ said Dr Anandhi Upendran, director of biomedical innovations at the MU School of Medicine Institute for Clinical and Translational Science and co-author of the recent study.

The new device delivers laser light via a fibre-optic cable to a wristband worn by the person being tested. The spectrometer can detect fat, protein, collagen and glucose molecules in the skin.

The glucose present in the blood causes a shift in wavelength in the laser light that can be detected and used to measure glucose levels.

In the published study, Evaluation of accuracy dependence of Raman spectroscopic models on the ratio of calibration and validation points for non-invasive glucose sensing, the researchers measured blood glucose levels of 20 healthy, non-diabetic adults prior to drinking a glucose-rich beverage. Blood glucose levels were then measured at intervals over the next 160 minutes using three methods: spectroscopy via the new wristband, an IV blood test, and a finger prick. The results showed that the spectrometer measured glucose values as accurately as the finger prick test.

‘This is a technology that we have been pioneering for more than 20 years,’ said Dr Jeon Woong Kang, a research scientist at MIT’s Laser Biomedical Research Centre and a co-author of the study. ‘We know that handheld skin prick tests are not always accurate and may be uncomfortable for patients. The gold standard is intravenous blood testing, but frequent blood draws may not be an option for many patients. We were pleased to find that our initial results show Raman spectroscopy can measure glucose levels that are comparable to the finger stick devices. We hope that we can refine this method to be a non-invasive continuous glucose monitoring sensor.’

The Raman spectrometer developed by the University of Missouri School of Medicine and MIT

With more testing, the researchers hope spectroscopy can become an alternative method to test glucose levels in patients in clinical care settings who are not capable of frequent blood draws and, one day, in other settings as the technology becomes smaller and more portable. Future studies will examine the accuracy of the technology in patients with diabetes.

Primary funding for the study has been provided by the National Institutes of Health, the Samsung Advanced Institute of Technology, and the Office of Medical Research at the MU School of Medicine.

Getting ready for launch

RSP Systems, a company also developing non-invasive technology for testing blood glucose levels, has recently announced that it has raised €10.35 million across a Series B funding round. The investment follows an initial Series A funding round of €4.6 million in the first half of 2016, and a €2.4 million grant in November 2016 by the European Union under Horizon 2020. The Series B investment will be used to fund clinical trials using the company’s device, GlucoBeam, and to prepare the device for regulatory approval and market launch in Europe.

GlucoBeam is based on critical depth Raman spectroscopy, RSP’s clinically validated technology, which offers improvements over standard Raman spectroscopy for measuring concentrations of various substances in the interstitial fluid – the tissue fluid surrounding the cells of the body – non-invasively through the skin. The technology defines a specific depth beneath the skin where glucose can be measured.

In May 2018 the company published its first article, ‘Non-invasive monitoring of glucose successfully demonstrated in home-use’, in Plos One, which was written in collaboration with acknowledged leaders within the field of diabetes. The article reports on the development of a Raman spectrometer that was used in the home of diabetic patients to test glucose levels non-invasively. This study, the first of its kind conducted in a home environment, has demonstrated accuracy at levels comparable to continuous glucose monitors currently on the market.

Existing and new investors contributed to RSP’s latest funding round. Among the new investors is Trumpf Venture, the corporate venture arm of the Trumpf Group, a manufacturer of laser technology.

RSP System’s CEO, Andreas Jenne, said: ‘We are grateful for the loyal support of existing shareholders and are excited to have attracted new and equally savvy shareholders in this second closing. The participation of Trumpf Venture points to the fact that we are on track towards sourcing, production, and commercialisation; the timing of this could not have been better.’

Dr Dieter Kraft, managing director of Trumpf Venture, commented: ‘We are very happy to be part of the RSP support team. RSP Systems is expected to be the breakthrough innovator the medical industry has waited decades for. For Trumpf the investment allows insights to new application areas of photonic systems where we can bring additional value, based on our knowledge.’

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