Accelerating Patterned Vascularization Using Granular Hydrogel Scaffolds and Surgical Micropuncture

Abstract

Bulk hydrogel scaffolds are common in reconstructive surgery. They allow for the staged repair of soft tissue loss by providing a base for revascularization. Unfortunately, they are limited by both slow and random vascularization, which may manifest as treatment failure or suboptimal repair. Rapidly inducing patterned vascularization within biomaterials has profound translational implications for current clinical treatment paradigms and the scaleup of regenerative engineering platforms. To address this long‐standing challenge, a novel microsurgical approach and granular hydrogel scaffold (GHS) technology are co‐developed to hasten and pattern microvascular network formation. In surgical micropuncture (MP), targeted recipient blood vessels are perforated using a microneedle to accelerate cell extravasation and angiogenic outgrowth. By combining MP with an adjacent GHS with precisely tailored void space architecture, microvascular pattern formation as assessed by density, diameter, length, and intercapillary distance is rapidly guided. This work opens new translational opportunities for microvascular engineering, advancing reconstructive surgery, and regenerative medicine.

Porous Hydrogels for Immunomodulatory Applications

“…All the tested microgeltemplated porogel bioinks were based on different natural methacryloyl polymers, such as gelatin, hyaluronic acid, chitosan, and dextran, which all exhibited excellent printability with both lattice and tubular structures (Figure 7d). Sheikhi et al utilized a granular hydrogel scaffold (GHS) technique to develop poreforming hydrogels, which used three microgels of different sizes to precisely control the pore architecture of the hydrogel [57]. As shown in Figure 8a, gelatin methacryloyl droplets were first converted to microgels via physical crosslinking at 4 °C, and subsequently, they formed a GHS by photo-crosslinking-induced packing and chemical assembly.…”

“…Microgel templating uses complex extraction steps, particularly if the application requires the template to be completely removed to regulate cell behavior. Sheikhi et al utilized a granular hydrogel scaffold (GHS) technique to develop poreforming hydrogels, which used three microgels of different sizes to precisely control the pore architecture of the hydrogel [57]. As shown in Figure 8a, gelatin methacryloyl droplets were first converted to microgels via physical crosslinking at 4 • C, and subsequently, they formed a GHS by photo-crosslinking-induced packing and chemical assembly.…”

Visible-Light Cross-Linkable Multifunctional Hydrogels Loaded with Exosomes Facilitate Full-Thickness Skin Defect Wound Healing through Participating in the Entire Healing Process

“…13,14 Currently, photoinduced injectable hydrogels based on gelatin methacrylate (Gel-MA) are extensively utilized for wound repair and tissue regeneration owing to their facile handling, biocompatibility, and ability to fill irregular wounds. 15,16 However, single-network Gel-MA hydrogels exhibit inadequate mechanical properties and toughness, rendering them unsuitable for incompressible deep wound repair. Moreover, most photoinduced hydrogels are crosslinked using UV light which may potentially accelerate organ/ tissue aging and exert detrimental effects on cells.…”

“…Hydrogels are considered as highly promising options for wound dressings because of their adjustable physical properties, good biocompatibility, moisture retention capacity, and 3D porous structure resembling the extracellular matrix. − In particular, the injectable hydrogels can be directly administered into the wound site and gelatinized in situ to effectively fill irregular wounds, thereby enhancing tissue adhesion. , Currently, photoinduced injectable hydrogels based on gelatin methacrylate (Gel-MA) are extensively utilized for wound repair and tissue regeneration owing to their facile handling, biocompatibility, and ability to fill irregular wounds. , However, single-network Gel-MA hydrogels exhibit inadequate mechanical properties and toughness, rendering them unsuitable for incompressible deep wound repair. Moreover, most photoinduced hydrogels are cross-linked using UV light which may potentially accelerate organ/tissue aging and exert detrimental effects on cells. , Consequently, the employment of visible light irradiation for cross-linking has attracted much attention in the biomedical field owing to its deeper penetration than UV light and rapid induction of cross-linking under mild conditions. , …”