According to new atlas, although we have seen skin patches that can detect individual substances in blood, a new skin patch has more functions. It can measure glucose, alcohol and lactic acid at the same time, and can have a variety of applications**
The device was designed by a team of engineers at the University of California, San Diego - based on previous research, the thick coin shaped prototype device consists of two connected parts.
At the bottom is a disposable array of microneedles, each about one-fifth the width of human hair. When the whole device is pressed on the skin, these needles painlessly penetrate the upper layer of the skin and make contact with the stroma surrounding the skin cells. The concentration of chemicals in the liquid is consistent with that in the blood.
At the top is a reusable box that includes electronic devices - including batteries, electrical sensors, microprocessors and Bluetooth modules. The box and the microneedle array are almost always connected together unless the used array is pulled down and replaced with a new one.
There is an enzyme on the tip of the microneedle, but not all needles have the same enzyme - some microneedles react with glucose in the stroma, while others react with alcohol and lactic acid. In all cases, the reaction produces a small current whose intensity varies with the level of chemicals detected in the stroma.
Therefore, by analyzing which needles are transmitting current -- and how strong -- it is possible to determine how much glucose, alcohol and lactic acid are currently in the blood. This information is wirelessly transmitted to an application on the smartphone and displayed on the screen.
The ability to measure glucose is certainly useful for patients with diabetes, and real-time measurement of alcohol in blood can provide users with an objective means to know whether they drink too much. In addition, people with diabetes can check these two readings because drinking alcohol reduces glucose levels.
At the same time, monitoring lactic acid can help athletes understand the degree of muscle fatigue they are experiencing. Similarly, this information may be useful for patients with diabetes because physical activity affects the body's ability to regulate glucose.
In testing the technology, five volunteers wore the device on their upper arms while eating, drinking and exercising. Its glucose, alcohol and lactic acid readings were found to be closely related to those obtained by commercial blood glucose monitors, respiratory alcohol detectors and laboratory blood lactic acid measurements, respectively.
Professor Patrick Mercier, co-author of a paper on the study, said: "in terms of clinical effectiveness and relevance, we start with a really good place for this technology. This reduces the barriers to clinical transformation."
The device is currently being commercialized by aquilx, a derivative of the University of California, San Diego.