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3D bioprinting of collagen to rebuild components of the human heart

A 3D printing technique was prepared for constructing complex collagen scaffolds for engineered biological tissues. Collagen gels are controlled by adjusting the pH value, and can provide a resolution of up to 10 microns upon printing. Cells can be embedded into collagen or introduced into the scaffold by embedding a gelatin sphere. Collagen is the main component of the human extracellular matrix. Fabof collagen scaffolds capable of reproducing the structure and function of tissues and organs has proven challenging. We present a 3D bioprinting collagen method using the free-form reversible embedding of a suspended hydrogel (FRESH) to design human heart components of various scales from capillaries to the entire organ. Control of pH driven gelation provides 20 micrometer filament resolution, a porous microstructure capable of rapid cellular infiltration and microvascularization, and mechanical strength for fabrication and perfusion of multiscale vasculature and trefoil lobes. We found that FRESH 3D bioprinted hearts accurately recapitulated patient-specific anatomical structures determined by microcomputed tomography. Ventricles imprinted with human cardiomyocytes show synchronous contraction, directed action potential propagation, and wall thickening of up to 14% during peak contraction.