Porous silicone paves the way for wearable biosensors that breathe
Biosensors that can be worn on the skin promise some exciting possibilities, with the potential to non-invasively monitor everyday health, and even things like glucose or stress levels. Scientists at Binghamton University have made a breakthrough that could make them more comfortable to wear and the signals they produce a lot clearer, showing off a new type of porous silicone that allows for the evaporation of sweat.
The researchers used a silicone called polydimethylsiloxane (PDMS) as their starting point, which is a material often used in the development of biosensors due to its biocompatibility and pliable nature. What this solid, non-porous material doesn’t offer, however, is breathability, which can cause problems on a couple of fronts.
“In athletic monitoring, if you have a device on your skin, sweat can build up under that device,” says study author Matthew Brown. “That can cause inflammation and also inaccuracies in continuous monitoring applications.”
Brown and his colleagues were able to produce a porous form of PDMS through what’s known as electrospinning, where fluids are first drawn through an electrical field that breaks them down into microscopic fibers. This production method led to the creation of a new material that performed similarly to collagen and elastic fibers of the human epidermis in mechanical testing, while also offering adhesive properties that enable it to stick to human skin.
The team tested out the performance of the porous PDMS through a series of experiments, and confirmed that it allowed sweat to evaporate during exercise and that a high-resolution signal was maintained throughout. A non-porous PDMS being tested alongside it did not allow for the evaporation of sweat and produced a lower resolution signal as a result.
Along with sweat, the porous material also allows for the passage of small molecules and gas. According to the team, this means it could be integrated with body tissues to open up a range of possibilities, including wound-healing, oxygen and carbon dioxide monitoring or even implantable devices that incorporate human cells.
“You can use this in a wide variety of applications where you need fluids to passively transfer through the material – such as sweat – to readily evaporate through the device,” Brown says.
The research was published in the journal Advanced Materials Technology.
Source: Binghamton University