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complement each other and jointly affect the quality and speed of wound healing.

Studies have shown that the expression of VEGF is obviously lower than that of normal

wounds, which seriously hinders the migration ability of endothelial cells and the
formation of tubular structures, leading to the blockage of angiogenesis, which in turn

leads to insufficient blood supply in the wound, limited delivery of nutrients and oxygen,

and poor discharge of metabolic waste, which seriously delays the healing process 116,117
.
3D printing technology mainly builds hydrogel scaffolds with bionic multi-level

channels and fully interconnected micronetworks by precisely manipulating the spatial

structure of biomaterials, simulating the structural and functional characteristics of the

natural vascular system from both physical topology and cellular microenvironment

levels, thereby promoting angiogenesis and tissue regeneration. Yongxiang Luo et al. 118

utilized 3D printing technology to construct a hydrogel scaffold with a fully

interconnected microchannel network that mimics the structure of natural blood vessels,

guiding the directional arrangement of endothelial cells and angiogenesis. This

achieved the integrated and precise manufacturing of macropores and microchannels,

enhancing nutrient transport and cell survival capabilities. This hydrogel scaffold has
demonstrated the ability to promote blood vessel growth towards the central region both

in vivo and in vitro, solving the problem of insufficient vascularization in traditional

119
tissue engineering. The 3D-printed hydrogel prepared by Shahabaj S. Mujawar et al.
provided an ideal physical scaffold for cell migration and vascular growth through its

precisely fabricated interconnected porous structure. The aloe vera extract carried in it

can actively release bioactive factors that promote angiogenesis, effectively reduce

inflammation and oxidation, and synergistically optimize the wound microenvironment.

Ultimately, it efficiently promotes vascularization and achieves high-quality tissue

repair by accelerating granulation tissue formation, collagen deposition and epithelial

regeneration, while reducing scar formation.

Hydrogels can provide physical topological guidance and support for endothelial

cell migration and tubular structure formation by precisely simulating the three-

dimensional porous structure and mechanical properties of ECM. Its high water content

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