Evaluations in live animal models: (a) upper: image of a bioresorbable multilayer photonic cavity structure implanted inside a surgically opened pocket at a subcutaneous region of a mouse. Lower: image of the surgical suture to close the pocket with the device implanted; (b) reflection spectra obtained using a fiber-coupled spectrometer pressed against the skin above the device. Placing the mouse onto a heating blanket increased the body temperature, as captured with the device and with a commercial sensor (Neurolog, Inc.); (c) measured positions of resonant peaks as a function of temperature. The plot indicates a linear relation between these peaks and the temperature; (d) calibrated temperature measured by the bioresorbable device compared with those obtained using a commercial thermometer; (e) reflection spectra of a bioresorbable multilayer photonic cavity collected in real-time while implanted in the subcutaneous region of an awake mouse housed at room temperature (23°C); (f) calculated standard deviation of peak positions extracted from these spectra. The measurements of resonant peaks at short-wavelength regime (from 500 nm to 600 nm) show a lower standard deviation induced by motion artifact, compared with those at long-wavelength regime (from 600 nm to 800 nm).