Photocurable and Temperature-Sensitive Bioadhesive Hydrogels for Sutureless Sealing of Full-Thickness Corneal Wounds

Penetrating corneal wounds can cause severe vision impairment and require prompt intervention to restore globe integrity and minimize the risk of infection. Tissue adhesives have emerged as a promising alternative to suturing for mitigating postoperative complications. However, conventional water-soluble adhesives suffer formidable challenges in sealing penetrating corneal wounds due to dilution or loss in a moist environment. Inspired by the robust adhesion of mussels in aquatic conditions, an injectable photocurable bioadhesive hydrogel (referred to as F20HD5) composed of polyether F127 diacrylate and dopamine-modified hyaluronic acid methacrylate is developed for sutureless closure of corneal full-thickness wounds. F20HD5 exhibits high transparency, wound-sealing ability, proper viscosity, biodegradability, and excellent biocompatibility. It allows in situ cross-linking via visible light, thereby providing sufficient mechanical strength and adhesiveness. In vivo, the adhesive hydrogel effectively closed penetrating linear corneal incisions and corneal injuries with minimal tissue loss in rabbits. During the 56-day follow-up, the hydrogel facilitates the repair of the injured corneas, resulting in more symmetrical curvatures and less scarring in distinction to the untreated control. Thus, bioinspired hydrogel holds promise as an effective adhesive for sealing full-thickness corneal wounds.

In Situ 4d Printing of Polyelectrolyte/Magnetic Composites for Sutureless Gastric Perforation Sealing

In situ bioprinting has emerged as one of the most promising techniques for the sutureless tissue sealing of internal organs. However, most existing in situ bioprinting methods are limited by the complex and confined printing space inside the organs, harsh curing conditions for printable bioinks, and poor ability to suturelessly seal injured parts. 4D printing is a technique in which the shape, properties, or functionality of inks or products can be controllably varied over time under external stimuli. The combination of in-situ bioprinting and 4D printing is a promising technique for tissue repair. Herein, we report the in-situ 4D printing of polyelectrolyte/magnetic composites by gastroscopy for sutureless internal tissue sealing. Using gastric perforation as an example, a gelatin/sodium-alginate/magnetic (GSM) bioink was developed, which can be precisely located by a gastroscope with the assistance of an external magnetic field, solidified in gastric fluid, and firmly adhered to tissue surfaces. The solidified gelatin/sodium alginate/magnetic complexes (GSMCs) along the defect can be attracted by an external magnetic field, resulting in sutureless gastric perforation sealing. The working mechanism of the printed GSMC was explained by a numerical simulation method using the COMSOL software. A demonstration using a porcine stomach with an artificial perforation confirmed the feasibility of sutureless perforation using 4D printing. Moreover, an in vivo investigation on gastric perforation in a rat model identified the biocompatibility by H&E and CD68+ staining. This study provides a new orientation and concept for functionality-modified in-situ 4D bioprinting. This article is protected by copyright. All rights reserved.