Page 271 - IJB-9-6

International Journal of Bioprinting 3D bioprinting for vascular system

4.1. Bio-inks with good performance epithelial cells and stimulate the formation of vascular
Making a printable pro-angiogenic bio-ink includes buds in the wound surface . Bacterial cellulose is an
[47]
mixing multiple hydrogels and chemically modifying organic compound biosynthesized by Gluconacetobacter
a single hydrogel. Substances that improve rheology or xylinus. After dehydration, the bacterial cellulose matrix
elasticity are added to compound bio-inks to optimize the can generate a microchannel structure for cell adhesion
mechanical properties of naturally derived hydrogels. Wu and proliferation in the vascular scaffold and promote the
et al. synthesized a shrinkage glycyrrhizin-methacrylate silk construction of a smooth muscle layer in the vascular wall
(SilkMA) with excellent mechanical properties and mixed (Figure 3B) . De-cellularization of tissues is a promising
[48]
it with GelMA and sodium alginate . They found that the technique that allows the removal of cellular components
[42]
higher concentrations of GelMA (7.5%) and SilkMA (20%) while preserving ECM structure and composition. By
were better suited for cell adhesion and proliferation, and mixing pig ovary dECM solution with seaweed gelatin
by using this method, they rapidly generated an inch-long mixture solution, the printed ovarian 3D scaffold
[42]
blood vessel construct in as little as 3 days . Xanthan showed more positive signals for new angiogenesis, cell
[49]
gum is a microbial extracellular polysaccharide produced proliferation, and survival (Figure 3C) . ECM not
by fermentation engineering, which has good rheology handled thoroughly poses a threat to the body’s immune
and biocompatibility. Muthusamy et al. utilized xanthan response or pathogen transfer. Oliveira et al. solved this
gum as a collagen thickener and found that collagen bio- problem using a cell assembly extracellular matrix (CAM)
ink with 10 pc xanthan gum added has the best printing synthesized from normal skin fibroblasts in vitro . The
[50]
adaptability, shape fidelity, and good capillary network thick structure printed by CAM can support the survival
generation . Laponite is a montmorillonite nanoclay and maturation of capillary networks and successfully
[43]
suspension that self-assembles to form a reversible shear- connect with the host circulatory system to establish
dilute gel. Laponite and alginate nanocomposite showed active perfusion .
[50]
improved rheological properties, printing compatibility, Sacrificial bioprinting is a classic indirect bioprinting
and higher recovery rate after shear under higher clay method. Sacrificial bioprinting of vascularized tissue
concentration, and the constructed bone tissue scaffold removes soluble bio-inks, usually through temperature
showed in vitro angiogenesis ability . Poly (itconic acid- change or enzymatic ablation, leaving behind a perfusable
[44]
co-citrate-co-octanediol) and poly (octanediol-co-maleic channel. Indirect printing is usually bioprinting based on
anhydride-co-octanediol) are synthetic elastic polymers extrusions with low resolution and minimum characteristic
that can be mixed with hydrogels to improve their stability sizes larger than 100 μm, making them less suitable for
and elasticity. Cell traction or body movement prevents the fabricating capillary structures. How to improve the
resulting blood vessels from irreversible deforming . resolution of sacrificial bioprinting is a new research
[45]
Endothelial cells can regulate vascular inflammation direction. Li et al. combined a heat-sensitive polymer
and thrombosis, and rapid endothelialization of early (n-isopropyl acrylamide) with biocompatible GelMA to
[51]
vascular grafts can effectively prevent the blockage of form a heat-responsive hydrogel . In cell culture, the
small-diameter vessels. The biological properties of thermo-responsive hydrogel underwent significant volume
bio-inks are essential for the rapid endothelialization of shrinkage, which effectively triggered the production
vascular grafts. To improve the ability of hydrogel scaffolds of smaller microscale vasculatures, with a minimum
[51]
to promote the formation of microvascular networks, diameter of 50 µm . Thomas et al. have proposed a two-
substances that can induce the adhesion and proliferation component biomaterial system using a photo-crosslinked
[52]
of endothelial cells can be added to the composite bio-ink. methacrylate hyaluronic acid (HAMA) and GelMA .
Natural alginate is biologically inert but can be modified With highly-resolution enzyme-digested photo inks based
with cell adhesion peptides to customize its biological on hyaluronic acid and the complementary enzyme, they
activity with excellent performance, precision, and control. printed vascular structures using stereolithography 3D
[52]
To promote vascular morphogenesis, Barrs et al. modified bioprinting .
alginate scaffolds to promote vascular morphogenesis
using RGD (an integrin-binding peptide for cell adhesion) 4.2. High-resolution printing technology
and vascular endothelial growth factor (VEGF) mimic Currently, most microvascular networks are constructed
peptides (Figure 3A) . Paeonia lactiflora extract is a by an uncontrolled spontaneous induction because
[46]
compound derived from the herb peony that regulates previous printing techniques have not been able to
the inflammatory microenvironment in skin wounds. accurately print microvessels with an internal diameter of
Combining 3% paeoniflorin with a 3D mesh structure fewer than 500 microns. The vascular network formed by
of the scaffold can promote the secretion of collagen by self-assembly, which is less efficient in material exchange

Volume 9 Issue 6 (2023) 263 https://doi.org/10.36922/ijb.0012