Temporary In Situ Hydrogel Dressings for Colon Polypectomies

Abstract

Currently, no dressings are utilized after removal of polyps during a colonoscopy rendering these tissue sites susceptible to bleeding, sepsis, and perfusion. We report the design specifications, synthesis, and ex vivo evaluation of in situ polymerized hydrogels as colon wound dressings post polypectomy. The hydrogels exhibited varied properties to include moduli between 100 and 16 000 Pa, dissolution times between 4 h to 7 days or longer, swelling up to 200%, and adhesion to colon tissue from 0.1 to 0.4 N/cm 2 . The hydrogels displayed minimal cytotoxicity, prevented the migration/spread of bacteria, and exhibited rapid gelation, a requirement for application to the lumen of the colon via an endoscope. This work highlights the structure−property relationship of hydrogels prepared from Nhydroxysuccinimide functionalized PEG cross-linkers and hyperbranched polyethylenimines or 4-arm PEG-NH 2 star polymers, and their potential as colon wound dressings.

Advances in Hydrogel Adhesives for Gastrointestinal Wound Closure and Repair

“…Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are well-established interventions to remove early and middle-stage tumors from the gastrointestinal tract and their use reduces the incidence and mortality of GI cancer [ 25 ]. However, adverse events arise from endoscopic resection including intraprocedural bleeding, delayed bleeding, delayed perforation, hemorrhaging, and sepsis [ 25 , 26 , 27 ], with delayed bleeding being the most common and affecting 3–12% of patients [ 28 ]. Clinically, electrocoagulation, argon plasma coagulation, and mechanical clip placement are used to control bleeding and close the mucosal defect post EMR or ESD [ 29 ].…”

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

“…Thiol–thioester exchange reaction with CME occurs at a physiologically relevant pH (7.4) and exhibits increased reaction kinetics at basic pH. The CME concentration controls the dissolution time, where increasing the CME concentration from 0.3 to 0.5 M at pH 7.4 decreases the dissolution time from 1 h to 36 min, respectively [ 79 ]. Cook et al.…”

“…Cook et al . also report a dissolvable hydrogel containing internal ester linkages, susceptible to degradation via hydrolysis [ 79 ]. The hydrogel contains a PEG backbone in the crosslinker, reacted with succinic anhydride to provide internal esters, capped with NHS functional groups.…”

Editorial: Special Issue on Advanced Biomedical Hydrogels

“…Another strategy by Cho and colleagues is the introduction of a tissue adhesive moiety into chondroitin sulfate hydrogels for effective cartilage repair through on-site localization of implanted hydrogels without deformation . Lastly, Grinstaff and colleagues developed wound dressings to be applied after polyp removal to address issues with bleeding, sepsis, and perfusion . Hydrogels were fabricated from poly­(ethylene glycol) and polyethylenimines and investigated for limited toxicity, bacterial growth, and rapid gelation for delivery via an endoscope.…”

“…26 Lastly, Grinstaff and colleagues developed wound dressings to be applied after polyp removal to address issues with bleeding, sepsis, and perfusion. 27 Hydrogels were fabricated from poly(ethylene glycol) and polyethylenimines and investigated for limited toxicity, bacterial growth, and rapid gelation for delivery via an endoscope. Such hydrogel approaches may be useful for numerous applications in tissue repair, where advanced hydrogels provide the appropriate signals for complex tissue repair processes.…”