The wearable skin sensor that can wirelessly detect the presence of CRP in human sweat. (Credit: Caltech)

A first-of-its-kind wearable skin sensor can wirelessly detect the presence of C-reactive protein (CRP) in human sweat. The sensor will make it easier for patients and medical professionals to monitor their health without the need for more invasive blood tests.

CRP, which is secreted by the liver, is so commonly associated with inflammation that its presence in the bloodstream is a strong indicator of an underlying health condition. The CRP sensor is built upon laser-engraved graphene, a sheet-like form of carbon. The graphene structure contains many tiny pores that create a large amount of surface area. Those pores are embedded with antibodies that bind to CRP and special molecules (redox molecules) capable of generating a small electric current under certain conditions.

The sensor also contains gold nanoparticles that carry with them a separate set of CRP antibodies (detector antibodies). Because each gold nanoparticle contains multiple detector antibodies, they amplify the minuscule signal that a single CRP molecule would otherwise provide.