Scientists from the University of Sussex have developed biodegradable health sensors comprised of natural materials. These sensors are both more sensitive than conventional synthetic sensors and are much more environmentally friendly. The details of this research have been published in ACS Sustainable Chemical Engineering.
The new sensors are made entirely of natural materials: seaweed, rock salt, water, and graphene. Consequently, they are entirely biodegradable and have minimal environmental impact. They are also considered “edible electronics,” which are electronics that can be safely consumed by a person for monitoring bodily processes from within the body. Finally, these sensors outperform polymer-based synthetic sensors that are the current standard. Because the natural sensors are more sensitive than their synthetic counterparts, they record a person’s vital signs more accurately. According to the study, their "sustainable graphene algae hydrogels were so sensitive that they could measure an object just 2mg in mass, equivalent to a single rain droplet, impacting their surface." The sensors also have the largest piezoresistive (a change in the electrical resistance as a result of pressure) response of “any hydrogel in the literature,” which makes them ideal for pressure-sensing use cases.
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To create these sensors, the researchers added graphene to a seaweed mixture, resulting in a thin, electrically conductive film. They then soaked the film in a salt bath and the film absorbed the water, becoming a conductive hydrogel from which sensors can be made.
Future development of this technology could revolutionize health monitoring. For instance, the researchers envision these sensors being adapted into a type of “second skin” or temporary tattoo; they would be safe to use, easy to apply, lightweight, and lack the cumbersome wires that some synthetic sensors have.
The technology may have applications in a variety of settings, ranging from consumer-level monitors that joggers wear to clinical-grade sensors used in hospitals.
