Bioadhesive hydrogels demonstrating pH-independent and ultrafast gelation promote gastric ulcer healing in pigs

Abstract

Hydrogels are soft materials used in an array of biomedical applications. However, the in situ formation of hydrogels at target sites, particularly in dynamic in vivo environments, usually requires a prolonged gelation time and results in poor adhesion. These limitations cause considerable loss of both hydrogel mass and encapsulated therapeutic cargoes, thereby compromising treatment outcomes. Here, we report the development of a hydrogel based on thiourea-catechol reaction to enhance the bioadhesion. Compared with classical bioadhesive hydrogels, our hydrogels show enhanced mechanical properties, exceedingly short curing time, and pH-independent gelation with a much lower oxidant concentration. We further report the robust adhesion of our hydrogels to acidic gastric tissues and easy delivery to the porcine stomach via endoscopy. The delivered hydrogels adhered to ulcer sites in vivo for at least 48 hours. Hydrogel treatment of gastric ulcers in rodent and porcine models accelerated ulcer healing by suppressing inflammation and promoting re-epithelization and angiogenesis. The improved retention of proregenerative growth factors and reduced exposure to external catabolic factors after hydrogel application may contribute to the observed therapeutic outcomes. Our findings reveal a promising biomaterial-based approach for treating gastrointestinal diseases.

Injectable Self‐Healing Natural Biopolymer‐Based Hydrogel Adhesive with Thermoresponsive Reversible Adhesion for Minimally Invasive Surgery

“…We further compared the underwater adhesiveness of Gel–GS by using lap‐shear adhesion test. [ 30 ] The results showed that the adhesive strength of the hydrogel decreases after being immersed in phosphate‐buffered saline (PBS), which may be due to weakening of the hydrogen bonding interactions between the hydrogel and tissue (Figure S10, Supporting Information). However, the underwater adhesive strength does not change significantly over time (from 1 to 12 h), which indicated the Gel–CS hydrogel remains adhered to the tissue even underwater.…”

Nanoparticle‐Assembled Vacuolated Coacervates Control Macromolecule Spatiotemporal Distribution to Provide a Stable Segregated Cell Microenvironment

“…The catechol groups in pH 2 buffers were less oxidized than the catechol groups in pH 7.4 buffer as evidenced by the less pronounced quinone peak (around 400 nm) in UV–vis absorption spectra (Figure S9, Supporting Information). [ 16 ] Therefore, the striking contrast between the vacuole stability at pH 2 and pH 7.4 indicates that the fusion‐resistant stability of the vacuoles is due to the consumption of catechol by oxidation at pH 7.4 and the associated increase in cross‐linking density. The significantly increased diameter of vacuoles within N 2 ‐protected NPA (H 1 ) coacervate under a physiological environment (pH 7.4, 37 °C) further revealed the role of catechol–quinone oxidation in stabilizing the vacuoles over time (Figure S10, Supporting Information).…”

Cellulose fibers-reinforced self-expanding porous composite with multiple hemostatic efficacy and shape adaptability for uncontrollable massive hemorrhage treatment

“…Meanwhile, in recent years, plenty of experimental hemostatic materials have been developed and used for rapid wound sealing and bleeding control, including sponges or foams, microspheres or beads, gauzes or zeolites, and functional hydrogels [ 49 , 50 ]. Previous studies have proven that some of these materials show the ability to control mild bleeding of artery or heart and promote wound healing [ 34 , 51 ]. However, because of slow hemostatic performance, low hemostatic efficacy, poor mechanical strength and flexibility, these hemostats are ineffective or unsuitable for treating aortic trauma or large/irregular wounds.…”