Fig. 5
Temporally controlling cell behavior using on-demand supramolecular displacement. a Dex-TAB was reversibly functionalized with BMP7-binding desthiobiotinylated VHH (D-@BMP7) to demonstrate the temporally controlled sequestration of BMP7 as visualized using BMP reporter cells. b Encapsulating cells in Dex-TAB did not significantly affect cell viability (i.e., live/dead) on the short-term (0 days) and long-term (7 days). Furthermore, cell viability and metabolic activity (i.e., MTT) were not significantly affected by the post-modification of Dex-TAB with neutravidin, D-@BMP7, and B-@BMP7. “n.s.” indicates no significance (p > 0.1; Kruskal-Wallis ANOVA test). c Bioluminescence analysis of the BMP reporter cells confirmed the reversible sequestration of BMP7 by Dex-TAB hydrogel through its on-demand competitive supramolecular complexation with neutravidin, D-@BMP7, and free biotin. “n.s.” indicates no significance (p > 0.1). Asterisk indicates significance (p < 0.05; Kruskal-Wallis ANOVA test). d Due to its stronger affinity with neutravidin than D-@BMP7, e the growth factor sequestering effect of biotinylated BMP7-binding VHH (B-@BMP7) could not be reversed by free biotin supplementation, thereby confirming the specificity of the desthiobiotin/biotin-based supramolecular displacement mechanism. “n.s.” indicates no significance (p > 0.1). Asterisk indicates significance (p < 0.05; Kruskal-Wallis ANOVA test). All scale bars indicate 100 µm
