Figure 4.

a) Programmable shape changes of trilayer CHA (O10M20A/GelMA/O10M45A) with encapsulated cells undergoing chondrogenesis and biochemical quantification of DNA content and GAG/DNA at each time point. *p < 0.05 compared to groups D1, D2, and Ctrl2. b) Programmable shape changes of trilayer CHA with encapsulated cells undergoing osteogenesis and biochemical quantification of DNA content, ALP/DNA, and calcium/DNA at each time point. ^*,#,& p < 0.05 compared to all groups with a different symbol or lacking a symbol. Ctrl1 stands for GelMA only hydrogel bar cultured in chondrogenic media at D21 (in (a)) or osteogenic media at D28 (in (b)), and Ctrl2 stands for trilayer hydrogel bar cultured in growth media at D21 (in (a)) and D28 (in (b)). c) Shape changes of GelMA/O10M45A bilayer derived from the O10M20A/GelMA/O10M45A trilayer during 3‐week culture in chondrogenic media: preprogrammed shape morphing (group 1), shape inversion at W1 by Ca²⁺ stimulation and subsequent culture to D21 (group 2), and shape recovery at W2 by EDTA and subsequent culture to D21 (group 3). d) DNA content and GAG/DNA ratios of all conditions at D21. Ctrl1 stands for GelMA only hydrogel bar cultured in chondrogenic media at D21. Ctrl2 stands for bilayer (GelMA/O10M45A) hydrogel bar cultured in growth media at D21. *p < 0.05 compared to all other groups. GRP1, GRP2, and GRP3 stand for group 1, group 2, and group 3, respectively. Black scale bars in the hydrogel photographs indicate 2 mm. Data are presented as mean ± SD, N = 3. Statistical tests were performed using one‐way ANOVA.