Tiny, bendable biosensors hold the promise of allowing health-care providers to track patients’ vital signs without them having to be tethered to bulky machines. But the difficulty of squeezing sophisticated circuitry onto surfaces no wider than a postage stamp makes designing such devices especially tricky.
To overcome this challenge, Zhenan Bao, PhD, a professor of chemical engineering at Stanford, and colleagues combined layers of flexible materials into pressure sensors to create a small skin-like heart monitor that can be attached to the wrist with a regular-sized adhesive bandage. A Stanford news release offers more details about the device and its potential uses in health care:
When the sensor is placed on someone's wrist using an adhesive bandage, the sensor can measure that person's pulse wave as it reverberates through the body.
The device is so sensitive that it can detect more than just the two peaks of a pulse wave. When engineers looked at the wave drawn by their device, they noticed small bumps in the tail of the pulse wave invisible to conventional sensors. Bao said she believes these fluctuations could potentially be used for more detailed diagnostics in the future.
Doctors already use similar, albeit much bulkier, sensors to keep track of a patient's heart health during surgery or when taking a new medication. But in the future Bao's device could help keep track of another vital sign.
"In theory, this kind of sensor can be used to measure blood pressure," said [Gregor Schwartz, a post-doctoral fellow and a physicist for the project]. "Once you have it calibrated, you can use the signal of your pulse to calculate your blood pressure."
This non-invasive method of monitoring heart health could replace devices inserted directly into an artery, called intravascular catheters. These catheters create a high risk of infection, making them impractical for newborns and high-risk patients. Thus, an external monitor like Bao's could provide doctors a safer way to gather information about the heart, especially during infant surgeries.
The team's work is described in paper published today in Nature Communications.
Previously: Touch-sensitive, self-healing synthetic skin could yield smarter prosthetics, Beetle wing design inspires ultra-sensitive electronic skin, Stanford researchers develop transparent, stretchable skin-like sensor and Stretchable solar cells could power electronic ‘super skin’