The hot field of research now in medical electronics is developing non-invasive sensors to measure the health parameters of human body. One such development in this week is development of paper-thin skin like sensor to sense heart beat. Engineers at Stanford university have combined layers of flexible materials into pressure sensors to create a wearable heart monitor thinner than a currency note. The flexible skin-like monitor can be worn under an adhesive bandage on the wrist, is sensitive enough to help doctors detect stiff arteries and cardiovascular problems.
To make the heart monitor both sensitive and small, The researcher Zhenan Bao, a professor of chemical engineering at Stanford team used a thin middle layer of rubber covered with tiny few microns sized pyramid bumps. When pressure is put on the device, the pyramids deform slightly, changing the size of the gap between the two halves of the device. This change in separation causes a measurable change in the electromagnetic field and the current flow in the device.
The more pressure placed on the monitor, the more the pyramids deform and the larger the change in the electromagnetic field. Using many of these sensors on a prosthetic limb could act like an electronic skin, creating an artificial sense of touch.
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.
These sensors are also said to help in measuring blood pressure in future.