Temporary In Situ Hydrogel Dressings for Colon Polypectomies

Fast-Gelling Polyethylene Glycol/Polyethyleneimine Hydrogels Degradable by Visible-Light

The treatment of burn wounds remains a clinical challenge due to the need for repeated dressings changes. Therefore, the development of a dressing system that can be atraumatically removed from the wound bed can be considered a breakthrough and improve treatment times. In this work, the development of an injectable, fast-gelling hydrogel is proposed that can change its mechanical properties when exposed to visible light. The hydrogels are prepared by a "click" amino-yne reaction between poly(ethylene glycol) (PEG) functionalized with propiolic acid and the amino groups of poly(ethyleneimine) (PEI). The hydrogels exhibit a fast gelation time, which can be adjusted by changing the weight percentage and molecular weight of the precursors. They also exhibit good swelling ability and adhesion to living tissues. More importantly, their mechanical properties changed upon irradiation with green light. This loss of properties is achieved by a 1 O2 -mediated mechanism, as confirmed by the degradation of the β-aminoacrylate linker. Moreover, the in vitro cell compatibility results of the hydrogels and their degradation products show good cytocompatibility. Therefore, it is believed that these hydrogels can be considered as materials with great potential for an innovative strategy for the treatment of burn wounds.

Advances in Hydrogel Adhesives for Gastrointestinal Wound Closure and Repair

Millions of individuals undergo gastrointestinal (GI) tract surgeries each year with common postoperative complications including bleeding, perforation, anastomotic leakage, and infection. Today, techniques such as suturing and stapling seal internal wounds, and electrocoagulation stops bleeding. These methods induce secondary damage to the tissue and can be technically difficult to perform depending on the wound site location. To overcome these challenges and to further advance wound closure, hydrogel adhesives are being investigated to specifically target GI tract wounds because of their atraumatic nature, fluid-tight sealing capability, favorable wound healing properties, and facile application. However, challenges remain that limit their use, such as weak underwater adhesive strength, slow gelation, and/or acidic degradation. In this review, we summarize recent advances in hydrogel adhesives to treat various GI tract wounds, with a focus on novel material designs and compositions to combat the environment-specific challenges of GI injury. We conclude with a discussion of potential opportunities from both research and clinical perspectives.

Hydrogels for the management of second-degree burns: currently available options and future promise

Burn wounds result from exposure to hot liquids, chemicals, fire, electric discharge or radiation. Wound severity ranges from first-degree injury, which is superficial, to fourth-degree injury, which exposes bone, tendons and muscles. Rapid assessment of burn depth and accurate wound management in the outpatient setting is critical to prevent injury progression into deeper layers of the dermis. Injury progression is of particular pertinence to second-degree burns, which are the most common form of thermal burn. As our understanding of wound healing advances, treatment options and technologies for second-degree burn management also evolve. Polymeric hydrogels are a class of burn wound dressings that adhere to tissue, absorb wound exudate, protect from the environment, can be transparent facilitating serial wound evaluation and, in some cases, enable facile removal for dressing changes. This review briefly describes the burn level classification and common, commercially available dressings used to treat second-degree burns, and then focuses on new polymeric hydrogel burn dressings under preclinical development analyzing their design, structure and performance. The review presents the follow key learning points: (1) introduction to the integument system and the wound-healing process; (2) classification of burns according to severity and clinical appearance; (3) available dressings currently used for second-degree burns; (4) introduction to hydrogels and their preparation and characterization techniques; and (5) pre-clinical hydrogel burn wound dressings currently being developed.