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Multicomponent bioprinting based on microfluidic printheads

A B C

D E F

G H I

Figure 7. Printing heterogeneous constructs through coaxial microfluidic printheads. (A) Schematic of the coaxial microfluidic printhead.
(B) Photograph of the coaxial microfluidic printhead. Scale bar=1 cm. (C) Heterogeneous grid structure (25 layers) printed through using
the coaxial microfluidic printhead. Scale bar=2 mm. (D) Schematic of rotating substrate for creating concentric ring “on-the-fly.” (E and F)
Fabrication of a heterogeneous concentric ring. Scale bars are 2 mm and 1 mm, respectively. (G) Fabrication of multicellular (H9C2 and
HUVEC) concentric rings through coaxial microfluidic printhead. Scale bar=4 mm. (H and I) Fluorescence microscopy image (top view)
of multicellular rings. Scale bars are 1 mm and 500 µm, respectively.

did not move while the collecting substrate rotated and constructs spatially incorporated with different
along printhead as the center. Figure 7E and F shows a materials such as particles and cells. Moreover, the
heterogeneous concentric ring with the yellow-coded and constructs consisting of continuous compositional
green-coded alginate hydrogel at the inner and outer side, gradient can be fabricated by dynamically altering the
respectively. As a proof of concept, a multicellular concentric flow rates during printing, which is difficult for the
ring was fabricated “on-the-fly” with the diameter of about multicomponent system with separated printheads to
8 mm (Figure 7G). Most of the red H9C2s distributed at the achieve. It was found that the rotating printhead enabled
inner side, while green HUVECs mainly distributed at the printing the filaments of heterogeneous morphology
outer side (Figure 7H and I). This printing method shows along different printing directions. The coding of
the promise to fabricate artificial vessels with multilayer in diverse materials on the printed filaments could offer
an “on-the-fly” way, especially those with large diameters a new way to create functional constructs. Coaxial
such as the inferior vena cava whose internal diameter is microfluidic printheads could significantly improve
approximately from 1.7 cm to 2 cm. the cross-linking condition. Further exploration of
printing multimaterial/cellular concentric rings through
4. Conclusion the rotating collecting substrate will allow fabrication
of artificial vessels efficiently. The proposed method
Here, we demonstrated a multicomponent bioprinting is able to print heterogeneous construct with different
technique based on microfluidic printheads for components as designed flexibly, which shows promise
printing heterogeneous constructs. The microfluidic for a various applications including tissue engineering
printhead enables printing of heterogeneous filaments and soft robots.

46 International Journal of Bioprinting (2019)–Volume 5, Issue 2