Fig. 5: Characterization of hydrogels.

a Schematic representation of crosslinking of 8-arm (PEG-SQ)8 (MW = 20,000 g mol−1) via photocycloaddition to form a hydrogel under irradiation of light. Gelation process of a polymer solution (c = 7.5 mM) followed by the evolution of the storage modulus G’ as a function of time; b under irradiation of different wavelengths using an LED light source (WheeLED Mightex); and c irradiation at λ = 470 nm and at different pH values. d G’ values at quantitative gelation from different polymer concentrations between 1 and 10 mM (error bars represent standard deviation from a mean value of 3 measurements). e Temporal control of the gelation process of polymer solution with c = 7.5 mM by switching light on and off at different time intervals.