Reactive Oxygen/Nitrogen Species–Scavenging Hydrogels for the Treatment of Inflammatory Diseases

Abstract

Various inflammatory diseases are developed from chronic inflammation. In inflammatory process, reactive oxygen species and reactive nitrogen species play important roles in signaling between immune cells. When inflammation progresses chronically, reactive oxygen species and reactive nitrogen species accumulate excessively in the inflammatory lesions, and they generate chemical species, which are stronger oxidants and damage the surrounding normal tissues, thereby exacerbating inflammation. Therefore, by scavenging overexpressed reactive oxygen/nitrogen species, the oxidative stress caused by them can be reduced, and through this, it is intended to alleviate inflammatory diseases. In this study, moieties that respond to reactive oxygen species and reactive nitrogen species were introduced into biocompatible polymers. And hydrogels formed by the polymers were used to form the injectable scaffold into the inflammatory lesions. Polymerized phenylboronic acid can be combined with polyvinyl alcohol, hydrophilic polymer in which a 1, 3-diol group is present, making phenylboronic ester bond that can scavenges reactive oxygen species. Through this process, phenylboronic esters were formed, and polymers were cross-linked to form a hydrogel. In addition, by introducing an o-phenylene diamine group, a moiety that scavenges reactive nitrogen species, to biocompatible hyaluronic acid, the polymer that scavenges reactive nitrogen species were synthesized. So after all polymers loaded in dual syringe were injected from it, injectable hydrogel was formed. This hydrogel, which can scavenge reactive oxygen/reactive nitrogen species, can be injected locally to the inflammatory area and expected to effectively alleviate inflammation by reducing oxidative stress. In addition, the hydrogel has an excellent ability to load the drug molecules in its porous network. Therefore, if the anti-inflammatory drug is loaded in the hydrogel, the drug will be gradually released and the effect of continuous inflammation treatment will be seen. Through this, it is expected to develop an efficient inflammatory disease treatment system and examine its biological application potential.