Fig. 4

Dissolution of Ca-alginate hydrogel by CD_lys. (A) Ca-alginate hydrogel, (B) Ca-alginate hydrogel incubated with 18 mg/mL CD_Lys, (C) 18 mg/mL CD_lys, (D) CD_Lys added with Ca²⁺ (final concentration 3mM), (E) surface morphology of Ca-alginate hydrogel, (F) cross section morphology of Ca-alginate hydrogel treated with CD_1/4 for 15 min, (G) cross section morphology of Ca-alginate hydrogel treated with CD_3/4 for 15 min, (H) morphology and (I) EDS mapping of surface of Ca-alginate hydrogel treated with CD_3/4 for 15 min, (J) morphology and (K) EDS mapping of surface of Ca-alginate hydrogel treated with CD_1/4 for 15 min, (L) morphology and (M) EDS mapping of centrifugal precipitation of Ca-alginate hydrogel treated with CD_1/4, (N) XRD spectra, (O) FTIR of calcium precipitations, (P) absorption of CD_lys solutions from ninhydrin tests, (Q) rheological analysis and (R) swelling of hydrogel during degradation by CD_1/4 solutions