A Bioprinted Tubular Intestine Model Using a Colon‐Specific Extracellular Matrix Bioink

Abstract

Tremendous advances have been made toward accurate recapitulation of the human intestinal system in vitro to understand its developmental process, and disease progression. However, current in vitro models are often confined to 2D or 2.5D microarchitectures, which is difficult to mimic the systemic level of complexity of the native tissue. To overcome this problem, physiologically relevant intestinal models are developed with a 3D hollow tubular structure using 3D bioprinting strategy. A tissue-specific biomaterial, colon-derived decellularized extracellular matrix (Colon dECM) is developed and it provides significant maturation-guiding potential to human intestinal cells. To fabricate a perfusable tubular model, a simultaneous printing process of multiple materials through concentrically assembled nozzles is developed and a light-activated Colon dECM bioink is employed by supplementing with ruthenium/sodium persulfate as a photoinitiator. The bioprinted intestinal tissue models show spontaneous 3D morphogenesis of the human intestinal epithelium without any external stimuli. In consequence, the printed cells form multicellular aggregates and cysts and then differentiate into several types of enterocytes, building junctional networks. This system can serve as a platform to evaluate the effects of potential drug-induced toxicity on the human intestinal tissue and create a coculture model with commensal microbes and immune cells for future therapeutics.

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“…For example, Jang and colleagues used porcine heart, liver, and colon dECM and further fabricated these into light-sensitive bioinks and further bioprinted them into microtissues with controllable sizes ( Kang et al, 2022 ). In another report the same group employed porcine colon dECM to bioprint a tubular intestine model to recapitulate the human intestinal system in vitro ( Han et al, 2022 ).…”

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“…( F,G ) 3D coaxial bioprinting assisted with photocrosslinking. Reproduced from Han et al ( 61 ) with permission from the publisher.…”

“…3D bioprinting using hydrogel bioink with cells in TE applications is categorized into four types according to their ink-dispensing method: laser-assisted printing, stereolithography, inkjet printing, and microextrusion printing ( 87 ). Harnessing bioprinting has established a new pillar of engineering intestinal tissues in vitro ( 58 , 59 , 61 , 88 , 89 ). Lian et al ( 59 ) described an embedded bioprinting strategy using a dual-layered support base to produce a vertical array of intestinal villi with dimensions close to the native tissue (100–200 µm in diameter and ≈2 mm in length) ( Figure 3D ) ( 90 ).…”

“…Although tubular structures of epithelial organs have been of great interest to TE researchers ( 72 , 96 – 105 ), there have only been a few studies on the subject of culturing intestinal epithelial cells (IECs) on the inner surface of the hollow structure until recently. Unique advantages that such hollow tubular shapes can offer in intestinal models include (a) accessibility to both the apical and basolateral side of the intestinal epithelium, which is necessary to study trans-epithelial transport ( 106 ); (b) extending the lifespan of the intestinal tissue model via perfusion through the lumen ( 107 ); (c) intraluminal oxygen gradient, which is critical in the mutual interaction between intestinal microbiomes and altered epithelium condition ( 108 ); (d) accelerated differentiation of IECs ( 61 , 71 ). In this regard, subsequent sections explore representative fabrication methods for 3D hollow tubular intestinal models.…”

“…This approach was further developed by Han et al ( 61 ) to enhance the intestine-specific functions of the model based on the dERS bioink ( Figure 3F ). The hollow tubular intestinal model was fabricated again with Caco-2 and colon dERS but some important printing parameters (e.g., initial cell density, bioink, and photoinitiator concentration) were fine-tuned.…”