Multicomponent bioprinting of heterogeneous hydrogel constructs based on microfluidic printheads.

Multimaterial bioprinting provides a promising strategy to recapitulate complex heterogeneous architectures of native tissues in artificial tissue analogs in a controlled manner. However, most of the existing multimaterial bioprinting techniques relying on multiple printing nozzles and complicate control program make it difficult to flexibly change the material composition during the printing process. Here, we developed a multicomponent bioprinting strategy to produce heterogeneous constructs using a microfluidic printhead with multiple inlets and one outlet. The composition of the printed filaments can be flexibly changed by adjusting volumetric flow rate ratio. Heterogeneous hydrogel constructs were successfully printed to have predefined spatial gradients of inks or microparticles. A rotary microfluidic printhead was used to maintain the heterogeneous morphology of the printed filaments as the printing path direction changed. Multicellular concentric ring constructs with two kinds of cell types distribution in the printed filaments were fabricated by utilizing coaxial microfluidic printhead and rotary collecting substrate, which significantly improves the printing efficiency for multicomponent concentric structures. The presented approach is simple and promising to potentially print multicomponent heterogeneous constructs for the fabrication of artificial multicellular tissues.