Skip to main content
. 2020 Jan 17;6(3):eaay0065. doi: 10.1126/sciadv.aay0065

Fig. 3. Tunable degradation of light-triggerable hydrogel.

Fig. 3

(A) Light intensity drops as a function of distance from the light source and the number of LEDs (365 nm). Inset: Schematic of array placement over light meter sensor. (B) Degradation of oNB-PAAM (4 M PAAM with 0.1 mol % oNB cross-linker) as a function of exposure time and distance from the three-LED array 365-nm light source (n = 3). (C) Effect of changing the percentage of oNB linker on ultraviolet (UV) light responsiveness of 4 M PAAM gels. Increasing the percentage of oNB linker leads to more significant drops in mechanical properties after 45-min degradation at 365 nm (n = 3, P < 0.05). (D) Effect of changing light wavelength from 365 to 405 nm. Shorter wavelengths lead to more significant drops in mechanical properties of 4 M PAAM gels with 0.1 mol % oNB cross-linker after 45-min degradation (n = 3, P < 0.05). (E) In vitro toxicity study on two cell lines (HT29 and Caco-2) of oNB-PAAM gels after degradation compared to negative control (− Control, untreated cells) and positive control (+ Control, cells treated with methanol), showing no significant effect of degradation by-products on cell viability (n = 4, P < 0.05).