Figure 6.

Orthogonal functionalization of DA cross-linked hydrogels using tetrazine ligation. (A) Schematic depicting covalent modification of DA hydrogels prepared from ELP–fulvene and 8-arm PEG functionalized with maleimides (black) and tetrazines (purple) with a tetrazine-reactive dye (CF640R-BCN, red). (B) Quantification of fluorescence intensity in gels with either excess maleimide or tetrazine moieties and either treated or untreated with tetrazine-reactive dye. ***P < 0.001, one-way ANOVA with Bonferroni post-hoc test. Data are mean ± s.d., n = 4.