3D Bioprinting of Human Hollow Organs

Abstract

3D bioprinting is a rapidly evolving technique that has been found to have extensive applications in disease research, tissue engineering, and regenerative medicine. 3D bioprinting might be a solution to global organ shortages and the growing aversion to testing cell patterning for novel tissue fabrication and building superior disease models. It has the unrivaled capability of layer-by-layer deposition using different types of biomaterials, stem cells, and biomolecules with a perfectly regulated spatial distribution. The tissue regeneration of hollow organs has always been a challenge for medical science because of the complexities of their cell structures. In this mini review, we will address the status of the science behind tissue engineering and 3D bioprinting of epithelialized tubular hollow organs. This review will also cover the current challenges and prospects, as well as the application of these complicated 3D-printed organs.

Keywords: 3D bioprinting; bioinks; biomaterials; hollow organs.

Fig. 1

Steps of 3D bioprinting

Fig. 2

Simplified illustrations of 3D bioprinting types: A inkjet bioprinting, B laser-assisted printing, C extrusion bioprinting, and D Stereolithographic printing. Recreated from Mahfouzi et al. (29)

Fig. 3

Application of 3D bioprinting

Fig. 4

Structure of lungs and various pulmonary cells along with their location; reprinted with permission from Chang et al. (49), Copyright Wiley 2008

Fig. 5

Printed hydrogel containing the lung subunit during RBC perfusion and ventilation of air sacs; reprinted with permission from Grigoryan et al. (54), Copyright 2019 Science by CC BY 4.0

Fig. 6

The 3D bioprinted lungs’ structure

Fig. 7

Human heart structure

Fig. 8

Schematic concept diagram of 3D bioprinting of the heart. The patient’s omentum tissue is taken, and the cells are isolated from the extracellular matrix, before being processed into a customized thermosensitive hydrogel. The pluripotent reprogrammed cells are then differentiated into endothelial and cardiomyocyte cells before being encapsulated in a hydrogel to produce the bioinks used in 3D printing. The bioinks are then used to create vascularized patches and complicated cellularized structures, which are subsequently printed. The autologous designed tissue that emerged can be implanted back into the patient to replace or repair diseased or damaged organs with minimal risk of rejection. Reprinted with permission from Noor et al. (88); Copyright Wiley 2019

Fig. 9

A 3D-printed heart. B Freshly printed heart. C Post extraction heart; reprinted with permission from Noor et al. (88); Copyright Wiley 2019

Fig. 10

Schematic concept illustration of 3D bioprinted hollow tissue fabrication methods: A urethra graft, B esophagus graft, C intestinal epithelium construct, D dual-headed extrusion bioprinting, and E organoid printing. Reprinted with permission from Galliger et al. (48)

Fig. 11

A–D 3D bioprinting urethra printing, crosslinking, and immersion in media. Reprinted with permission from Zhang et al. (98)