Tunicate cellulose nanocrystals reinforced micropatterned hydrogels modulate mitochondrial maturation and...

Culturing cardiomyocytes in vitro with robust contractile capacity remains challenging due to the complex and diverse factors influencing contraction, such as cellular maturity, spatial distribution, and structural orientation. Herein, biomass-derived micropatterned hydrogels are fabricated via UV-induced polymerization, providing an anisotropic microenvironment for cardiomyocyte culture. This enables the precise regulation of mitochondrial networks within individual cardiomyocytes and the oriented organization of multicellular ensembles. As the elastic modulus of the tunicate cellulose nanocrystals (TCNCs) reinforced hydrogel is 50 kPa, the single-cell mitochondrial area increases to 560 μm², providing the energy foundation necessary for cardiomyocyte contraction. Moreover, the orientation degree of cardiomyocytes reaches 80% by precisely tuning the width of the surface microgroove to 40 μm, thereby facilitating the synchronized contractile activity in vitro for more than 10 consecutive days. Finally, flower-shaped bio-actuators driven by oriented cardiomyocytes are constructed to mimic the opening and closing motion of flowers. This work not only establishes a versatile biomimetic platform for engineering anisotropic microenvironments to support in vitro cardiomyocyte culture and maturation but also demonstrates significant potential for applications in biological microactuators.