If you’ve ever spent a significant amount of time in hospital you’ll know that one of the worst parts about the experience is having your blood pressure monitored continuously throughout the day. This usually involves strapping a medical device to the patient’s arm that either automatically inflates and deflates on a set schedule, or the patient needs to be woken up regularly to get for blood pressure measurements.
Now, it looks like this could soon be about to change. Engineers from the University of California San Diego have developed a soft, stretchy skin patch that can be worn on the neck to continuously track the number of vitals. The skin patch can track blood pressure and heart rate while measuring the wearer’s levels of glucose as well as lactate, alcohol or caffeine.
It is also the first wearable device that can monitor cardiovascular signals and multiple biochemical levels in the human body at the same time. Researchers behind the wearable believe it can be used to help people with underlying medical conditions to monitor their own health regularly.
In terms of the patch itself, the device is made from a thin sheet of stretchy polymers that can conform to the skin. It is equipped with a blood pressure sensor and two chemical sensors—one that measures levels of lactate (a biomarker of physical exertion), caffeine and alcohol in sweat, and another that measures glucose levels in interstitial fluid.
The blood pressure sensor sits near the centre of the patch. It consists of a set of small ultrasound transducers that are welded to the patch by a conductive ink. A voltage applied to the transducers causes them to send ultrasound waves into the body. When the ultrasound waves bounce off an artery, the sensor detects the echoes and translates the signals into a blood pressure reading.
The chemical sensors are two electrodes that are screen printed on the patch from conductive ink. The electrode that senses lactate, caffeine and alcohol is printed on the right side of the patch; it works by releasing a drug called pilocarpine into the skin to induce sweat and detecting the chemical substances in the sweat. The other electrode, which senses glucose, is printed on the left side; it works by passing a mild electrical current through the skin to release interstitial fluid and measuring the glucose in that fluid.
Take a look at the Skin Patch below:
According to Joseph Wang, a professor of nanoengineering at UC San Diego and co-corresponding author of the study, “We can collect so much information with this one wearable and do so in a non-invasive way, without causing discomfort or interruptions to daily activity.”
Picture: UC San Diego News Center