Hybrid Dry Powders for Rapid Sealing of Gastric Perforations under an Endoscope.

Effective wound sealing is key to prevent postoperative complications arising from gastric endoscopic submucosal dissection (ESD). Accurate delivery of the adhesive to wet and dynamic tissues and rapid action of the adhesive onsite should be considered for endoscopic operation. A hybrid dry powder (HDP) strategy, characterized by decoupling of powder gelation and tissue adhesion, for rapid sealing of wet tissues is presented. HDPs carrying oppositely charged polyelectrolytes become a hydrogel layer over the target tissue by absorbing the surrounding water and forming strong electrostatic interactions between heterogeneous components. Strong adhesion is realized through hydrogen bonding between the adhesive component, poly(acrylic acid), and the tissue. Wet tissue adhesion can be achieved in a few seconds (adhesion strength of ∼30 kPa to porcine skin). Notably, the HDP-assembled hydrogel can maintain a low swelling rate and resist degradation in acidic aqueous environments (pH 1). Furthermore, HDPs can be delivered to target tissues by spraying via an endoscope. The results of in vivo experiments indicate that healing of gastric ESD perforations by sealing with the powder-assembled hydrogel is as effective as that by sealing with clips. This strategy is expected to facilitate the development of fast-acting hydrogel-based adhesives for endoscopic operation.