FIGURE 4.

(A) Dissolution of the hydrogel after treatment with an aqueous cysteine methyl ester (CME) solution (0.3 m, pH 8.6) via thiol–thioester exchange (B) (Konieczynska et al., 2016). Images were adapted with permission from Konieczynska et al. (2016). Copyright 2016, John Wiley and Sons. (C) Degradation of different nanofibrous hydrogel (1 FHHA, 2 FHHA-S, 3 FHHA/Fe, and 4 FHHA-S/Fe) (Liu et al., 2020a). Crosslinking with Fe³⁺ increased the in vivo stability of hydrogel. FHHA, high molecular weight HA fibers; FHHA-S, thioether grafted high molecular weight HA fibers; FHHA/Fe, Fe³⁺ crosslinked high molecular weight HA nanofibrous hydrogel; FHHA-S/Fe, Fe³⁺ crosslinked thioether grafted high molecular weight HA nanofibrous hydrogel. Images were adapted with permission from Liu et al. (2020a). Copyright 2020, John Wiley and Sons.