Fig. 3. Kinetics of PhoCoil gel photodegradation.

(A) Gel softening in response to 405 nm light via oscillatory rheology time sweep. Rheology was conducted at 5% strain and 10 rad s⁻¹ with light intensity set to 10 mW cm⁻² at the gel. G’0 was defined as the storage modulus immediately before light exposure. Three independent gels were measured for each weight percentage. Data is presented as the mean (line) ± SD (shaded area). (B) Control of endpoint stiffness by modulation of light exposure time. 10 wt% gels were exposed to constant 10 mW cm⁻², 405 nm light (blue) or periods of 10 min light on, 10 min light off (gray). (C) Control of softening rate by modulation of light intensity. Three independent 10 wt% gels were measured for each intensity of 405 nm light. Data is presented as the mean (line) ± SD (shaded area). (D) When normalized for light dosage, experimental data from Panel C collapses onto a single curve, indicating PhoCoil photocleavage follows the same light dose-dependency for each intensity. (E) Control of endpoint stiffness by coformulation of PhoCoil with a non-light-responsive network-forming Coil protein. Three independent gels for each formulation were exposed to 10 mW cm⁻2, 405 nm light, with the total molar concentration of protein kept constant across formulations. Data is presented as the mean (line) ± SD (shaded area).