The Biosensors of the Future Can Be Drawn on With an Ordinary Ball-Point Pen

​The biosensors of the future could come ​courtesy of a ballpoint pen. Special sensor-outfitted inks may be simply drawn onto skin like an elementary school tattoo, offering capabilities ranging from blood sugar monitoring to the detection of environmental toxins. Such inks are now a real, if experimental thing, courtesy of researchers at the University of California, San Diego, who've published their work on "do-it-yourself electrochemical biosensors" in the ​current issue of Advanced Healthcare Materials.

The idea is pretty much just what it sounds. Roll on some enzyme-laden sensor ink and it will react with the body's chemistry in this or that way. Using a Bluetooth-enabled ​potentiostat, it could even be possible for the results to be beamed directly to a device or cloud service. It's easy enough then to imagine whole sensor networks implemented with simple doodles of electrochemically reactive inks.

For a diabetic used to pricking their finger on a regular basis, such a capability could be huge. Blood glucose monitoring is one of the things UCSD researchers implemented in their study, with the other being on-leaf detection of the industrial chemical phenol, a compound found in sunscreens and some cosmetics that also happens to be corrosive and pretty dangerous at the right concentrations. The ink could be modified in any number of ways to detect more substances.

Other ideas, for example, include sensing pollution in the forms of heavy metals or pesticides, detecting the presence of chemical warfare agents or explosives, but also really any other situation where knowing the chemical background of some surface or environment might be useful. If something is electrochemically reactive in some way, it can theoretically be sensed.

"Unlike prefabricated sensors, this approach empowers the end user with the ability of 'on-demand' and 'on-site' designing and fabricating of biocatalytic sensors to suit their specific requirement," the UCSD researchers write in the current study. "The bio­active pens produce highly reproducible biocatalytic traces with minimal edge roughness. The composition of the new enzymatic inks has been optimized for ensuring good biocatalytic activity, electrical conductivity, biocompati­bility, reproducible writing, and surface adherence." A single biopen could replace 500 glucose test strips, they note.

Becoming a cyborg (loosely) is as easy as scribbling.