Bioprinted vascular tissue: Assessing functions from cellular, tissue to organ levels

Abstract

3D bioprinting technology is widely used to fabricate various tissue structures. However, the absence of vessels hampers the ability of bioprinted tissues to receive oxygen and nutrients as well as to remove wastes, leading to a significant reduction in their survival rate. Despite the advancements in bioinks and bioprinting technologies, bioprinted vascular structures continue to be unsuitable for transplantation compared to natural blood vessels. In addition, a complete assessment index system for evaluating the structure and function of bioprinted vessels in vitro has not yet been established. Therefore, in this review, we firstly highlight the significance of selecting suitable bioinks and bioprinting techniques as they two synergize with each other. Subsequently, focusing on both vascular-associated cells and vascular tissues, we provide a relatively thorough assessment of the functions of bioprinted vascular tissue based on the physiological functions that natural blood vessels possess. We end with a review of the applications of vascular models, such as vessel-on-a-chip, in simulating pathological processes and conducting drug screening at the organ level. We believe that the development of fully functional blood vessels will soon make great contributions to tissue engineering and regenerative medicine.

Keywords: Assessment of function; Bioink; Bioprinting; Blood vessel; Vascularized structure.

Graphical abstract

Fig. 1

Function of bioprinted vascular tissues. Assessment and application at cellular, tissue and organ levels.

Fig. 2

Vascular branch formation steps. Reproduced and adapted with permission [80]. Copyright 2011, Springer Nature. A) In response to stimulation with angiogenic factors, quiescent vessels dilate and a particular EC is selected as the tip cell. B) The stem cells after the tip cells form a lumen by proliferation and finally fuse with the adjacent vessels by budding to form a neovascularization. C) After fusion of adjacent vessels, the lumen allows neovascular flow and restoration of quiescence through a series of further complex processes, with the end of vessel branch formation.

Fig. 3

Bioprinting techniques for fabricating vascular structures. A) Extrusion-based bioprinting: extrusion of single-layer tubular structures. Reproduced and adapted with permission [19]. Copyright 2021, John Wiley and Sons. B) Schematic diagram of microfluidic extrusion bioprinting of single and bilayer vascular structure. Reproduced and adapted with permission [11]. Copyright 2022, American Association for the Advancement of Science. C) Sequential fabrication of tissue and organ structures with complex external geometry and vascular structure using microgel biphasic (MB) hydrogel bioink and sacrificial bioink. Reproduced and adapted with permission [98]. Copyright 2023, John Wiley and Sons. D) Projection-based 3D printing system to construct complex vascular network structures. Reproduced and adapted with permission [28]. Copyright 2018, American Chemical Society. E) Continuous 3D printing process using UV-LED induced photopolymerization of photosensitive biomaterials, individually controlled DMD with continuous input of a series of digital masks while moving the printing platform. Reproduced and adapted with permission [29]. Copyright 2017, Elsevier. F) In situ formation of vascularized tissue models using femtosecond laser irradiation of collagen hydrogels.Reproduced and adapted with permission [99]. Copyright 2022, John Wiley and Sons.

Fig. 4

Characterization and use of vascular-associated cellular markers. A)-B) The marker CD31/VE-cadherin/vWF shows cellular junctions between monolayers of ECs. Reproduced and adapted with permission [158]. Copyright 2020, Springer Nature. Reproduced and adapted with permission [164]. Copyright 2016, Proceedings of the National Academy of Sciences. C) The vascular structure is composed of three layers of cells in which collagen IV represents the microvascular basement membrane Reproduced and adapted with permission [152]. Copyright 2018, Springer Nature. D) Confocal images of bifurcated vascular structures after 10 days of perfusion culture were obtained, and they were labeled with CD31, α-SMA, and VE-cadherin to visualize the fusion layer of HUVECs. Reproduced and adapted with permission [103]. Copyright 2022, John Wiley and Sons. E) Classification of vessels by determining the amount of α-actin. Reproduced and adapted with permission [165]. Copyright 2011, Wolters Kluwer Health, Inc. F)The H&E staining and Masson staining of bionic vascular vessel. Reproduced and adapted with permission [17].Copyright 2022, John Wiley and Sons.

Fig. 5

Interaction, growth and anastomosis between large diameter vessels and the capillary network of the surrounding tissue. A) A multi-scale vascular system manufactured using 3D bioprinting technology simulates the process of vessel growth and maturation. Reproduced and adapted with permission [171]. Copyright 2014, Springer Nature. B) Mechanical signals generated by perfusion culture, along with chemical signals such as GFs, synergistically enhance capillary-channel anastomosis. Reproduced and adapted with permission [8]. Copyright 2023, John Wiley and Sons. C) Hydrogels spontaneously form vessels and get attached to tubular scaffolds, allowing the microvascular system to be perfused. Reproduced and adapted with permission [176]. Copyright 2021, John Wiley and Sons.

Fig. 6

Vascular tissue with perfusability and perfusability. A) The vascular network achieved long-term perfusion. The endothelium provided a screen of barrier properties and permeabilities. Reproduced and adapted with permission [151]. Copyright 2016, Proceedings of the National Academy of Sciences. B)–C) Large diameter tubular structures were perfused in a specially designed fluid platform for processing. Reproduced and adapted with permission [157]. Copyright 2018, Elsevier. Reproduced and adapted with permission [189]. Copyright 2009, Elsevier. D) Pericytes-ECs co-localization and generation of new vessels at the tissue interface. Reproduced and adapted with permission [169]. Copyright 2012, American Chemical Society. E) Microvascular network fusion occurred within multicellular spheres. Reproduced and adapted with permission [183]. Copyright 2009, Elsevier. F) Neovascularization of the middle portion connected the vascular channels on both sides and fluorescent bead perfusion indicated blood flow through the neovascular networks. Reproduced and adapted with permission [190]. Copyright 2021, Springer Nature.

Fig. 7

Transplantation of the bioprinted vascular tissue where vascular anastomosis and perfusion occurred. A) The pre-vascularized tissue has a large number of endothelial vessels with RBCs, indicating successful anastomosis of the artificial vessel with the host vessel. Reproduced and adapted with permission [29]. Copyright 2017, Elsevier. B) Integration of the human-derived vascular network with the host vascular network. Reproduced and adapted with permission [206]. Copyright 2018, Springer Nature. C) Bioprinted loaded scaffolds (HUVECs-3LMS-GelMA) induce vascular growth after 4 weeks of subcutaneous implantation, exhibiting durable angiogenic properties. Reproduced and adapted with permission [38]. Copyright 2023, John Wiley and Sons. D) The assembled vascular system was strongly bound to the host tissue and abundant blood perfusion was observed both in the peripheral and central regions. Reproduced and adapted with permission [162]. Copyright 2017, Institute of Physics Publishing. E) Successful perfusion of blood flow following the establishment of anastomoses between the grafted tissue and the carotid artery as well as jugular vein. Reproduced and adapted with permissio [146]. Copyright 2021, John Wiley and Sons. F) Bioprinted conduits enable in vivo implantation into mouse vena cava and achieve perfusion through vascular anastomosis. Reproduced and adapted with permission [11]. Copyright 2022, American Association for the Advancement of Science.

Fig. 8

Applications of bioprinted vascular structure. A)-B) Simple large diameter vascular structures. Reproduced and adapted with permission [189]. Copyright 2009, Elsevier. Reproduced and adapted with permission [119]. Copyright 2019, Elsevier. C) Branched and linear vessels. Reproduced and adapted with permission [208]. Copyright 2022, American Chemical Society. D)-E) Complex multi-branching vascular structures. Reproduced and adapted with permission [204]. Copyright 2019, Elsevier. Reproduced and adapted with permission [208]. Copyright 2017, American Chemical Society. F) Biofabricated heart structures. Reproduced and adapted with permission [209]. Copyright 2019, American Association for the Advancement of Science. G) The renal model simulates albumin uptake and glucose reabsorption in vitro. Reproduced and adapted with permission [210]. Copyright 2019, Proceedings of the National Academy of Sciences. H) Skin model for dermatological modeling and wound healing. Reproduced and adapted with permission [211]. Copyright 2018, John Wiley and Sons. I) Bone tissue enhances osteogenic bone regeneration and vascular cell growth. Reproduced and adapted with permission [212]. Copyright 2016, Institute of Physics Publishing. J) Biomimetic tumor model to study drug diffusion behavior. Reproduced and adapted with permission [188,213]. Copyright 2019, John Wiley and Sons. K) Bionic Vascular and Lymphatic Vessel Models Containing Melanoma Spheroids. Reproduced and adapted with permission [214]. Copyright 2022, Wiley-VCH GmbH. L) Proximal renal tubule chip composed of mature renal tubules and vascular parts. Reproduced and adapted with permission [215]. Copyright 2020, Elsevier. M) Tumors model within a vascularized construct. Reproduced and adapted with permission [179]. Copyright 2018, John Wiley and Sons.