Precise,
real-time monitoring of temperature in flexible and bioconformable
formats finds applications in healthcare and disease diagnostics.
There is interest in the fabrication of biocompatible and biodegradable
devices that can be safely resorbed inside the body or easily disposed
of in the environment, reducing waste. Here, a fully organic, silk-protein-based
temperature sensor is reported with attractive properties such as
flexibility, transparency, conformability, durability, and biodegradability
together with high sensitivity and accuracy. The sensor is composed
of a flexible, photoactive silk fibroin substrate, on which interdigitated
electrodes are photolithographically micropatterned using a photoactive
silk sericin–PEDOT:PSS conductive ink. A temperature sensitive
layer comprising photoactive silk sericin and rGO is integrated on
the electrodes. Finally, the sensor is sheathed in a fibroin layer
to eliminate interference from humidity. The sensor exhibits a high
sensitivity of −0.99% °C−1 in the temperature
range of 20–50 °C along with excellent stability in humidity
from 10 to 90% RH. It possesses high cycling stability over multiple
heating/cooling cycles. These layers are covalently integrated, improving
mechanical stability and the retention of electrochemical behavior
under deformation. The sensor is shown for the monitoring of surface
temperature, including rapid measurement of skin temperature with
accuracy. Finally, the temperature sensor is able to effectively degrade
over a period of ∼10 days under proteolytic conditions. Such
sensors have potential in personalized healthcare monitoring devices,
improving efficient disease detection and diagnosis.