Soon, wearable device that assesses your health via sweat

A new wearable device may be able to use a person's sweat to provide significant information on the state of their health, scientists say.
A new sensor developed at the Nanoelectronic Devices Laboratory (Nanolab) at Ecole Polytechnique Federale de Lausanne (EPFL) could allow for a tiny adhesive electronic stamp attached to the arm, which can show one's level of hydration, stress or fatigue while jogging.
"The ionic equilibrium in a person's sweat could provide significant information on the state of his health," said Adrian Ionescu, director of Nanolab.
"Our technology detects the presence of elementary charged particles in ultra-small concentrations such as ions and protons, which reflects not only the pH balance of sweat but also more complex hydration of fatigue states.

"By an adapted functionalisation I can also track different kinds of proteins," Ionescu said.
The device is based on transistors that are comparable to those used in advanced microprocessors.

On the state-of-the-art "FinFET" transistor, researchers fixed a microfluidic channel through which the fluid to be analysed flows.
When the molecules pass, their electrical charge disturbs the sensor, which makes it possible to deduce the fluid's composition.
Due to the size of the transistors - 20 nanometres, which is one hundred to one thousand times smaller than the thickness of a hair - it is possible to place a whole network of sensors on one chip, with each sensor locating a different particle, researchers said.

"We could also detect calcium, sodium or potassium in sweat," Ionescu said.
The details of the device are published in the journal ACS Nano.