Fig. 2: Characterization of the GelMA and PDA@GelMA.

A Schematic illustration of the fabricated process of PDA@GelMA. B SEM images. Scale bar: 5 μm. C FTIR spectra. D Surface wettability. E XPS spectra. F The deconvolution of C1s and N1s peaks of GelMA. G The deconvolution of C1s and N1s peaks of PDA@GelMA. H Rheological properties of samples against frequency at 25 °C.