Tubular Bioartificial Organs: From Physiological Requirements to Fabrication Processes and Resulting Properties. A Critical Review

Abstract

In this featured review manuscript, the aim is to present a critical survey on the processes available for fabricating bioartificial organs (BAOs). The focus will be on hollow tubular organs for the transport of anabolites and catabolites, i.e., vessels, trachea, esophagus, ureter and urethra, and intestine. First, the anatomic hierarchical structures of tubular organs, as well as their principal physiological functions, will be presented, as this constitutes the mandatory requirements for effectively designing and developing physiologically relevant BAOs. Second, 3D bioprinting, solution electrospinning, and melt electrowriting will be introduced, together with their capacity to match the requirements imposed by designing scaffolds compatible with the anatomical and physiologically relevant environment. Finally, the intrinsic correlation between processes, materials, and cells will be critically discussed, and directives defining the strengths, weaknesses, and opportunities offered by each process will be proposed for assisting bioengineers in the selection of the appropriate process for the target BAO and its specific required functions.

The effect of bioactivity of airway epithelial cells using methacrylated gelatin scaffold loaded with exosomes derived from bone marrow mesenchymal stem cells

“…This concept simplifies the step of culturing stem cells in vitro and planting them into grafts. It also saves operating costs and time for future clinical practice, especially for patients who urgently need alternative treatments 4,39 . Its theoretical basis is to cultivate the cell‐scaffold complex in the bioreactor in vitro and then transplant it in situ in vivo, using the receptor's own environment as a natural bioreactor to promote the regeneration of transplanted tissue 8 .…”

Polymeric reinforcements for cellularized collagen-based vascular wall models: influence of the scaffold architecture on the mechanical and biological properties

“…More advanced techniques, include solution electrospinning (SES), three-dimensional (bio)printing (3D(B)P) and melt electrowriting (MEW) ( Holland et al, 2018 ; Robinson et al, 2019 ; Jeong et al, 2020 ). Each one of them has its strengths and weaknesses, and will influence the resulting properties of the fabricated tubular construct ( Pien et al, 2021b ). SES and MEW are techniques that enable the production of nano- and micro-scale fibers, respectively, constituting an advantage with regard to mimicking the natural ECM in terms of hierarchical organization and properties ( Bhardwaj and Kundu, 2010 ; Kade and Dalton, 2021 ).…”

“…Both 3D(B)P and MEW offer the possibility to design complex geometries through computer aided design ( Sears et al, 2016 ; Robinson et al, 2019 ). All three techniques present unique advantages to process materials serving tissue engineering applications, including vTE ( Pien et al, 2021b ).…”

Melt Electrowriting of a Photo‐Crosslinkable Poly(ε‐caprolactone)‐Based Material into Tubular Constructs with Predefined Architecture and Tunable Mechanical Properties

“…[28,29] Initially, MEW was established on planar collectors, but meanwhile, it has transitioned toward the fabrication of 3D tubular geometries [30,31] as various applications in regenerative medicine rely on such structures (including blood vessels, urethra, and ureters, intestine, nerve, etc.). [32] Therefore, research has been devoted toward the elaboration of methods to improve the design and fabrication of tubular scaffolds by exploiting specialized printer set-ups and mandrel collectors. [30,31] In this regard, the advantages of MEW (onto a rotating mandrel collector) offer great potential as they enable the generation of predefined architectures with high resolution, high porosity (i.e., >87%) [33] and interconnectivity due to the small fiber diameters.…”