Measuring blood glucose concentrations still requires direct access to blood, whether through a finger prick or via a continuous glucometer. MIT scientists working with colleagues at Samsung Advanced Institute of Technology in South Korea are reporting that they’ve developed a non-invasive blood glucose measurement device that may finally turn a long-held goal of medicine into reality.
The researchers, using a machine about the size of a printer, showed that it is possible to use Raman spectroscopy, a safe and non-invasive imaging technique, to measure the amount of glucose blood contains right through the skin.
Raman spectroscopy relies on spotting the visual signatures of light as it is scattered by various molecules, allowing to identify what those molecules are. Using near-infrared light, one can penetrate and assess the molecular composition of the interstitial fluid a couple millimeters below the surface of the skin, and the glucose within it is correlated to blood glucose levels. One major problem is that glucose is relatively rare, so its signal is hard to pick out from all the other molecules that are surrounding it.
“When you are measuring the signal from the tissue, most of the strong signals are coming from solid components such as proteins, lipids, and collagen. Glucose is a tiny, tiny amount out of the total signal,” said Jeon Woong Kang, one of the researchers of the study appearing in journal Science Advances. “Because of that, so far we could not actually see the glucose signal from the measured signal.”
Now the team was able to measure the glucose signal directly by shining light onto the skin at one angle and picking up the returning light from a different angle, an approach that was surprisingly effective. It resulted in a much better performance and lets the team pickup glucose Raman peaks while ignoring a lot of the signal coming from other components.
They verified their approach in lab pigs, but because their device is still quite big and bulky, there’s quite a bit of work still left to be done to scale it down so it is small enough for use by everyday people. “This is the first time that we directly observed the glucose signal from the tissue in a transdermal way, without going through a lot of advanced computation and signal extraction,” said Peter So, another researcher of this technology.
Study in journal Science Advances: Direct observation of glucose fingerprint using in vivo Raman spectroscopy