Fluidic Infiltrative Assembly of 3D Hydrogel with Heterogeneous Composition and Function

Abstract

3D hydrogels are powerful, multifunctional materials that are poised to become a building block in next‐generation systems. Modern schemes to print complex 3D hydrogels are advancing rapidly; however, they possess several limitations including—but not limited to—polymer incompatibility or difficulty in imparting continuous heterogeneity in composition or function. Here, a simple strategy of synthesizing programmable hydrogel systems with tunable form and function in 3D is presented. This approach utilizes commercially available stereolithographic printer/resin to fabricate high‐resolution molds followed by the programmed infiltration and gelation of hydrogel prepolymer. This mold is then sacrificed to yield 3D, multifunctional hydrogels exhibiting user‐defined heterogeneity. The approach is compatible with numerous in‐situ gelling polymers and modifiers ranging from interpenetrating networks of organic or synthetic polymers to functional materials possessing dense concentrations of nanomaterials or fluorescent markers. Accessible and versatile, this approach allows the fabrication of complex, multimaterial constructs with tunable 3D environmental responses inaccessible to well‐established hydrogel 3D printing methods.

Bioinspired Multifunctional Cellulose Nanofibril-Based In Situ Liquid Wound Dressing for Multiple Synergistic Therapy of the Postoperative Infected Wound

“…Hydrogels are one of the most common dressing materials used in wound healing after skin tumor surgery. , Hydrogels have elasticity similar to soft tissues owing to their 3D network structure and can support tissue regeneration. , They provide a tissue-like environment for wound healing and keep the wound moist. Moreover, bioactive molecules and drugs can be encapsulated in hydrogels and released through diffusion, further improving the therapeutic effect. , In comparison with aerogels and preformed hydrogels, for the irregular postoperative wounds, the in situ hydrogel has higher drug release efficiency and skin adhesive performance .…”

“…As a wound dressing substrate, flexible, fiber-like cellulose nanofibrils (CNFs) have excellent biocompatibility, highly porous structures, abundant chemical reaction sites, and good machinability. − As a matrix for wound dressings, CNF can be chemically modified to respond to different environmental stimuli, and its drug release behavior can be modulated by controlling these response properties. , Meanwhile, the nanosized CNF can form CNF-based hydrogels with nanocage structures showing an orderly arrangement in multiple dimensions, one of which is similar to the arcuate foot structure of Evarcha arcuate spiders . Consequently, the CNF-based hydrogel, consisting of a lot of water is similar to biological soft tissues, possesses excellent biomimetic stickiness, shape adaptability, film-forming ability, and high drug loading capacity. − Thus, CNF is an excellent substrate for preparing in situ hydrogel wound dressings for irregular tumor postoperative wound healing.…”

“…18,19 Hydrogels have elasticity similar to soft tissues owing to their 3D network structure and can support tissue regeneration. 20,21 They provide a tissue-like environment for wound healing and keep the wound moist. Moreover, bioactive molecules and drugs can be encapsulated in hydrogels and released through diffusion, further improving the therapeutic effect.…”

“…33,34 Meanwhile, the nanosized CNF can form CNF-based hydrogels with nanocage structures showing an orderly arrangement in multiple dimensions, one of which is similar to the arcuate foot structure of Evarcha arcuate spiders. 21 Consequently, the CNFbased hydrogel, consisting of a lot of water is similar to biological soft tissues, possesses excellent biomimetic stickiness, shape adaptability, film-forming ability, and high drug loading capacity. 30−32 Thus, CNF is an excellent substrate for preparing in situ hydrogel wound dressings for irregular tumor postoperative wound healing.…”

Hydrogel injection molding to generate complex cell encapsulation geometries

“…In plastic injection molding, for example, plastic precursor solutions are injected with high pressure into molds to form complex geometries with high fidelity and high reproducibility 11 . To date, complex molding techniques have shown promise with hydrogels alone 12 , but injection molding has not been exploited for the generation of complex cell-laden hydrogel geometries in the clinic or in scaled cell product manufacturing processes. In applications where a single hydrogel and cell type are required in a complex geometry, injection molding has the potential to be an efficient, intuitive, and reproducible approach to generate complex hydrogel constructs.…”