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International Journal of Bioprinting 3D bioprinting for vascular system

bioprinting generates discrete droplet accumulation for organ repair and transplantation. Here, we summarize
molding with higher precision. However, due to low driving five prerequisites for 3D printing to construct the
pressure, inkjet bioprinting cannot print materials with microvascular network: good bio-ink performance,
high viscosity or cells with high concentration, which limits high-resolution printing technology, suitable cell source,
its application scope. Photocurable bioprinting, which uses vascular micropattern guiding angiogenesis, and multi-
photosensitive materials for photocuring and stacking layer dimensional vascular network hierarchy appropriate to the
by layer, is a printing method with the highest accuracy and host vascular system.
has been used in the study of microvascular networks .
[14]
The design and development of bio-ink is the key to 2. 3D bioprinting of large-diameter vessels
bioprinting technology. The research, development, and and valves
synthesis of new bio-inks that can balance printability, 2.1. 3D bioprinting of large-diameter vessels
biocompatibility, and mechanical properties are the basis of Large-diameter vessels used for vascular replacement
3D bioprinting applications. There is currently a shortage require good mechanical properties, consistent host
of bio-inks with both good printability and angiogenic anatomy, and high cell survival. There are still some gaps in
activity, which is a major bottleneck for using bioprinting the anatomical correlation and cell survival rate of vascular
systems in blood vessel manufacturing. Hydrogels are grafts based on electrospinning. 3D bioprinting has an
the most commonly used bio-inks for constructing advantage in manufacturing with consistent anatomy
vascular stents because of their excellent biocompatibility. and high cell survival rates, as it can rely on computers to
Biocompatible hydrogels have a 3D network structure accurately model and utilize biocompatible bio-inks.
similar to the extracellular matrix (ECM), which can
promote cell adhesion and growth. Hydrogels contain First, the large-diameter vascular graft used in the
natural and synthetic categories. Naturally derived protein patient’s surgery should have the same anatomical structure
bio-inks, such as collagen, gelatin, and fibrin, generally as the host. The grafts mismatched with the patient’s
support cell adhesion and have good angiogenesis but blood vessels are more dangerous in the large blood
are not mechanically sufficient to be used directly as vessel graft, and 36.8% of patients were re-hospitalized
3D-printed vascular scaffolds [15,16] . Through various within 30 months due to heart failure caused by graft
chemical modifications, synthetic hydrogels, such as mismatch . The resolution of 3D bioprinting technology
[18]
polyethylene glycol and poloxamer, generally have good depends first on computer modeling and printing path
physical and chemical properties but are bioinert materials planning. Kucukgul designed a new computer algorithm
that are not conducive to cell adhesion and growth . to accurately print large-diameter blood vessel structures
[12]
Multi-material printing is the development trend of 3D with living cells through a self-supporting “cake-like”
bioprinting. Bio-inks with printability and angiogenic printing method [19,20] .
activity were produced by selecting different components Second, vascular wall smooth muscle cells are
with different bioactivity and mechanical properties and essential for the long-term stability of the great vessels.
adjusting their concentrations. By carefully regulating bio- Developing bio-ink with good cell compatibility is the key
ink formulation, a cellular microenvironment similar to to improving the survival rate of graft cells. The natural
that of natural blood vessels is constructed .
[17]
ECM contains laminin, fibrin, and cytokines that promote
According to the classification of vessel diameter cell adhesion and proliferation. Oropeza et al. found that
size, this paper summarizes the latest progress of 3D in decellularized ECM (dECM)-printed graft structures,
printing technology in large-caliber blood vessels and arterial smooth muscle cells could grow for a long time with
valves, small-caliber blood vessels, and microvascular no dead zone for 24 h. Because of smooth muscle cells, the
networks, including the advancement of high-resolution macrovascular graft can maintain mechanical elasticity for
[21]
printing technology and the preparation of bio-inks a longer period . Removing the ECM and adding bio-ink
with good mechanical and biological properties. In can significantly improve the cell survival rate of the graft.
addition, we briefly review the methods that promote the Potere et al. optimized the de-cellular protocol of the pig’s
cultivation and maturation of bioprinted vascular grafts. natural aorta and determined the optimal concentration
This review also aims to facilitate the efficient transition of dECM mixed into bio-inks . The printed structure
[22]
of bioprinted grafts from the bioprinting lab to the clinic. showed excellent structural stability and elasticity.
This paper also focuses on constructing a capillary
network with biological functions using 3D bioprinting 2.2. 3D bioprinting of vascular valves
technology and promoting tissue engineering development 3D printing technology provides a new and effective
method for manufacturing biological valves. Cardiac valve

Volume 9 Issue 6 (2023) 259 https://doi.org/10.36922/ijb.0012