At the University of Sandiego, engineers have developed a non-invasive wearable skin patch that measures blood pressure, heart rate, lactate, caffeine, and alcohol in sweat and Glucose in interstitial fluid. The stamp-sized patch comes in handy, particularly for patients suffering from blood pressure and diabetes who are the risk of falling ill. It is also highly beneficial for remote patient monitoring, especially during Covid-19, where social distancing is mandatory. The new soft, stretchy skin-patch can be worn on the neck that tracks blood pressure and heart rate. It also measures Glucose, lactate, caffeine, and alcohol in the sweat. The patch is hooked up to an external power source, and it displays the readings via a machine. The stamp-sized wearable patch is the output of the efforts made by the combined efforts of two different research ventures at the UC Sandiego Centre. One group involves scientists working on wearables (Director Wang’s lab), and the other team of engineers are concerned with advanced blood pressure monitors.
Anatomy and Details of the Non-invasive Wearable Skin Patch
The adhesive skin patch is basically a conglomerate of multiple sensors, each associated with measuring a particular parameter. It is a thin sheet containing three main sensors – one is a blood pressure sensor, and the other two are chemical sensors. The blood pressure sensor is present at the center of the patch. It consists of two electric transducers that are attached to the patch via conductive ink. When a voltage is applied to the transducers, it causes them to send ultrasonic waves into the body. These waves, when bounced off the artery, the sensor detects the echoes, which are then translated into a blood pressure reading.
The chemical sensors on the patch include two electrodes that are screen printed on the patch using conductive ink. The chemical sensor on the left is responsible for detecting lactate, caffeine, and alcohol. It works by releasing a drug called Pilocarpine, which induces the release of sweat into the body and thereby detects the chemical substances. The other electrode is screen printed on the left side and is responsible for the detection of the Glucose in the interstitial fluid. When activated, the sensor passes a mild electric current through the skin that triggers the release of interstitial fluid and measures the levels of Glucose in the process. The team is currently working to bring in a newer advanced version of the patch with more sensors to detect a wide array of biomarkers. The research study is published in the journal “ Nature Biomedical Engineering“.