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printed hydrogels, which achieved rapid and site-specific cross-linking through

bioorthogonal reactions to construct a more uniform 3D network structure. The

hydrogel exhibits exceptional hyperelasticity, shear-thinning/self-healing properties,
and an extremely low swelling ratio. Besides, the click chemical cross-linking process

effectively avoided the generation of toxic by-products, significantly improved cell

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survival rate and long-term encapsulation stability. Click chemical cross-linking
encompassed a variety of reactions, including Cu-catalyzed azo-alkynyl cycloaddition,

copper-free click reaction, strain-enhanced azo-alkynyl cycloaddition, and sulfyl-

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Michael addition. The combination of click chemical cross-linking and 3D printing
technology created a novel approach for fabricating hydrogels with precise structures

and superior functional properties, thereby offering new opportunities in biomedical

applications. The structure and shape of 3D printed hydrogels could be accurately

designed according to specific requirements, while click chemical cross-linking

ensured the formation of stable 3D network structures during the printing process,

facilitating the fabrication of complex structures with sub-micron precision. However,

limited research has been reported on the preparation of 3D printed hydrogels via click
chemical cross-linking strategy, which to some extent restricts the widespread adoption

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and in-depth advancement of this technology in the field. Jianan Rend et al. developed
a full peptide 3D printed hydrogel platform via a one-step thiolene click chemistry

method, enabling the encapsulation of VEGF165-overexpressing cells at physiological

temperatures and the fabrication of 3D hydrogel scaffolds with precisely controlled

cellular spatial distribution (Figure 3). DLP technology enabled the fabrication of high

resolution (up to 10 μm) and complex 3D structures, such as branching vascular

networks, through layer-by-layer curing, providing a novel idea for the application.

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