Fig. 2

Temporal control over biotinylated hydrogel. a Dextran was modified with tyramine and biotin to yield the injectable polymer Dex-TAB. b The phenolic hydroxyl groups in Dex-TAB could be enzymatically crosslinked in situ via the formation of C–C and C–O bonds (red bonds) using horseradish peroxidase (HRP) as catalyst and H₂O₂ as oxidizer. This effectively resulted in a dextran-based hydrogel with biotin available for orthogonal post-functionalization. c Dex-TAB (blue) and not Dex-TA (gray) could be post-functionalized with fluorescent streptavidin-FITC in a stable manner, as demonstrated using fluorescence recovery after photobleaching (FRAP). d On-demand supramolecular complexation and in situ displacement of biochemical moieties within Dex-TAB was demonstrated using D-FITC, B-ATTO, and pristine biotin (e, f), which was quantified using time-lapse fluorescence confocal microscopy analysis. All green data indicate D-FITC. All red data indicate B-ATTO. All error bars indicate ± standard deviation (n = 4). All scale bars indicate 10 µm