Pre-set extrusion bioprinting for multiscale heterogeneous tissue structure fabrication

Abstract

Recent advances in three-dimensional bioprinting technology have led to various attempts in fabricating human tissue-like structures. However, current bioprinting technologies have limitations for creating native tissue-like structures. To resolve these issues, we developed a new pre-set extrusion bioprinting technique that can create heterogeneous, multicellular, and multimaterial structures simultaneously. The key to this ability lies in the use of a precursor cartridge that can stably preserve a multimaterial with a pre-defined configuration that can be simply embedded in a syringe-based printer head. The multimaterial can be printed and miniaturized through a micro-nozzle without conspicuous deformation according to the pre-defined configuration of the precursor cartridge. Using this system, we fabricated heterogeneous tissue-like structures such as spinal cords, hepatic lobule, blood vessels, and capillaries. We further obtained a heterogeneous patterned model that embeds HepG2 cells with endothelial cells in a hepatic lobule-like structure. In comparison with homogeneous and heterogeneous cell printing, the heterogeneous patterned model showed a well-organized hepatic lobule structure and higher enzyme activity of CYP3A4. Therefore, this pre-set extrusion bioprinting method could be widely used in the fabrication of a variety of artificial and functional tissues or organs.

Bioprinting of Multiscaled Hepatic Lobules within a Highly Vascularized Construct

“…We previously reported that the preset extrusion bioprinting technique could create heterogeneous, multicellular, and multimaterial structures simultaneously, depending on the design of the preset cartridge. [ 15 ] In this study, we designed and fabricated a new preset cartridge that resembles the structure of a human hepatic lobule ( Figure ). A hepatic lobule is a building block of the liver parenchyma, which is composed of hepatocytes arranged in the liver cords within a sinusoid network and a central vein.…”

From Shape to Function: The Next Step in Bioprinting

“…C) Free‐form endothelialized vessels can be obtained via printing with sacrificial gels and further studied to understand angiogenic sprouting in 3D. Reproduced under the terms of the Creative Commons CC‐BY 3.0 License ( https://creativecommons.org/licenses/by/3.0/) . Copyright 2018, The Authors, published by IOPScience.…”

“…Recently, an elegant alternative has been developed to use extrusion technologies to load spatially organized patterns of multiple cell types and microscale vascular structures within a single filament. Instead of coordinating the flow of multiple bioinks from different reservoirs into the printing nozzle, a single, multicompartment cartridge was developed to lodge more than one bioink . As during printing these inks are extruded in parallel from the same nozzle, the produced filament is templated by the geometry and loading pattern in the cartridge.…”

“…With this latter shape, a hexagonal liver lobule model was prepared with HepG2 and endothelial cells, which were then cocultured, and compared to filaments printed with a conventional, single reservoir cartridge, having a single bioink with nonzonally distributed cells. Interestingly, the patterned coculture showed superior maturation of the hepatocytic cells compared to the nonorganized construct, resulting in improved proliferation and ability to respond to the delivery of rifampicin, as a model drug, by increasing the protein expression of cytochrome CYP3A4A, necessary to metabolize the compound . Although the exact mechanism for this improved cell maturation was not identified, this study further highlights the relevance of controlling cell positioning to improve tissue morphogenesis and allow biofabricated constructs to acquire functionalities expressed in native tissues.…”

“…Salient advances in the creation of tissues that exerted native functions in vivo have been achieved with precisely patterned, yet relatively simple architectures . At the same time, an increasing number of studies is emerging, suggesting improved maturation of biofabricated tissues mimicking native structures, particularly when multiple cell types are distributed in precise areas of the produced constructs . Bioprinting itself may help answer such fundamental yet elusive questions.…”