Reactive Oxygen Species‐Scavenging Nanomedicines for the Treatment of Oxidative Stress Injuries

Abstract

This Progress Report describes a development of two types of reactive oxygen species (ROS)-scavenging nanomedicines for the treatment of oxidative stress injuries, referred to as pH-sensitive redox nanoparticle (RNP(N) ) and pH-insensitive redox nanoparticle (RNP(O) ), which are prepared by self-assembling amphiphilic block copolymers possessing nitroxide radicals as a side chain of hydrophobic segment via amine and ether linkages, respectively. Due to a protonation of amino groups in hydrophobic core, RNP(N) disintegrates in low pH environments such as ischemic, inflamed, and tumor tissues, resulting in increased ROS-scavenging activity because of the exposed nitroxide radicals from the core. Utilizing pH-responsiveness of RNP(N) , it shows remarkable therapeutic effects on oxidative stress injuries such as renal and cerebral ischemia-reperfusion injuries after intravenous administration. Moreover, RNP(N) shows an enhancement of the activity of anticancer drugs by suppression of activation of transcription factors in tumor due to the ROS scavenging. On the other hand, orally administered RNP(O) has notable characteristics such as preferential accumulation in mucosa and inflamed area of gastrointestinal tract and no uptake into blood stream. Based on these characters, RNP(O) shows a remarkable therapeutic effect for the gastrointestinal inflammation without any adverse effects. Thus, ROS-scavenging nanomedicines have therapeutic efficacy in numerous oxidative stress diseases.

Anti‐Oxidizing Radical Polymer‐Incorporated Perovskite Layers and their Photovoltaic Characteristics in Solar Cells

“…Nitroxide radicals, TEMPO, and its polymeric analogue PTMA are redox‐active via one‐electron transfer and catalytically react with two molecules of highly reactive O 2 .− to generate one oxygen molecule and a less reactive hydrogen peroxide molecule (Figure S5). Such mechanism has been previously discussed by us for several redox reactions . The PTMA incorporated into the perovskite could capture O 2 .− formed upon light irradiation and oxygen exposure to suppress the degradation of the perovskite layer significantly, regardless of the type of underlayers.…”

“…Such mechanism has been previously discussedb yu sf or several redox reactions. [50,51,56,57] The PTMA incorporated into the perovskite could capture O 2 C À formed upon light irradiation and oxygen exposure to suppress the degradation of the perovskite layer significantly,r egardless of the typeo fu nderlayers. As described above,t he high-quality perovskite grains formed on incorporation of PTMA also contributed to the durability of the perovskite layer.Amonomeric compound of PTMA, that is, the nitroxide radical molecule TEMPO, was also incorporated in the perovskite.…”

“…Recently, Boudouris and co‐workers reported the high charge‐transporting capability of the TEMPO polymer . The TEMPO polymers have been also studied as an environmentally benign redox catalyst in biomedical and medical applications, where the TEMPO radical eliminates O 2 .− even in the vapor phase …”

“…[48,49] The TEMPO polymers have been also studied as an environmentally benign redox catalyst in biomedical and medical applications, where the TEMPO radical eliminates O 2 C À even in the vapor phase. [50,51] Herein, we incorporated, for the first time, the redox-active TEMPO radical polymer in ap erovskite layer to successfully improve the durability in an oxygen-containinga tmosphere and describedi ts effect in the significant suppressiono ft he degradation of perovskite compounds. Surprisingly, the incorporation of PTMA did not reduce the photocurrenti nt he perovskite layer due to its charge-transporting capability.T he effects of the PTMA as ascaffold for the formation of high-quality perovskitesare also described herein.…”

Nanosized silver (II) pyridoxine complex to cause greater inflammatory response and less cytotoxicity to RAW264.7 macrophage cells

“…From our fluorescence microscopic investigation and flowcytometric analysis, it was clear that the ROS-production ability of AgPyNPs in RAW264.7 cells was slightly inferior compared to AgNPs. This inferior ROS production is due to the antioxidative property of pyridoxine, which scavenges the ROS produced by silver ions [32]. These phenomena motivate our in-depth study to analyse the immune effect of AgPyNPs.…”