One of the most important developments in disease monitoring and diagnosis has been the rapid and accurate assessment of clinical conditions. Diabetes, one of the most prevalent treatable diseases, is one whose control has been greatly augmented due to the availability of simple, rapid glucose tests. Having full knowledge of one’s blood sugar levels lets one administer the proper dose of insulin. While not used long-term, continuous glucose monitoring (not really continuous; it currently takes 288 measurements per day) is used to determine trends in blood sugar levels (identify spikes or rhythms) that would not be noticed with the routine “finger spike” test samples.
Now, folks at MIT (back in the 70’s the mantra was: “MIT PhD, Money”- I am sure you can deduce the tune for said mantra) have developed a prototype light sensor that measures glucose levels transdermally. Right now, the device is a bit big for human applications (the size of a small crash cart), but first you prove the concept, then you can reduce its size. The light source for this device is near infrared (like that used in remote controls for your TV and your car).
Those of you who recall your high school (or college) physics recall that light is comprised of photons. These particles exhibit both wave- and particle-like behavior- and when they hit a somatic cell (body cells), they can be absorbed, traverse through the cell, or scatter. This provides a great deal of information about the contents, shape, and size of the cell. But, doing this test transdermally means one can only penetrate about 1 mm below the surface, and, at that level, one would only be measuring interstitial fluid (the fluid around the blood vessels) glucose levels. There is a lag between the changes of glucose level that occur within the blood and their manifestation interstitially. One must discern the lag time to be able to use any obtained data with certainty.
Ishan Barman and Chae-Ryon Kong, along with their professor Ramachandra Dasari, published just such an initial study in Analytical Chemistry. They found the lag for healthy volunteers to be between 8 and 10 minutes. Once they determined this lag, the light monitor predicted results that were 15 to 30% more accurate; precision increased by at least a factor of 3. It is thought that by redoing this analysis with diabetic patients (whose lag time would be different, since diabetes affects the blood vessels themselves), they can increase the utility of the device dramatically. And, at the same time, they are working on reducing the size of the device to one that can be worn or carried with ease.
This same technological concept could also be adapted to measure other chemicals in the blood, such as cholesterol and alcohol.
A short aside: To all those so inclined: A healthy, happy, and prosperous New Year. To some others: May Eid (terminating festival of Ramadan) bring you peace, happiness, and comfort.