Fig. 4

Comparison of hydrogels with and without GO-PL. a Overview of the appearances of both hydrogels. b SEM and the general view of the pore size change of the hydrogel before and after the PTT (scale bar = 100 μm). c Comparison of pore sizes of hydrogels before and after NIR exposure *P < 0.05. Unpaired t-test, two-tailed (n = 6). d SEM of hydrogels at room temperature or treated with mild PTT (scale bar = 500 μm). e, f Young's modulus for the hydrogel samples. g Stress-strain curves were observed over five compression cycles. Comparative analysis of the swelling ratios (h) and volume ratios (i), respectively. j Concentration curve depicting intermittent drug release from the hydrogel. k Cumulative release curve for the continuously released drug from the hydrogel