Photoelectrocatalytic inhibition of amyloid self-assembly by hematite photoanode

Abstract

The abnormal self-assembly of $\beta-amyloid$ ($A\beta$) peptides into $\beta$-sheet-rich amyloid aggregates and subsequent accumulation in the brain are pathological hallmark of Alzheimer’s disease (AD). Various kinds of photo-active inhibitor have been introduced to suppress the $A\beta$ aggregation using light sources

however, their application has been limited due to their incomplete metabolism in human body and poor permeability to blood brain barrier. Recently, there has been a report that the development of micrometer-scale implantable LED module has been successful, which motivated us to develop photoelectrode-based therapy of AD. Herein, we report on visible light-active hematite ($\alpha-Fe_2O_3$)-based photoanode as an inhibitor for suppression of $A\beta$ aggregation. The synthesized hematite photoanode has a suitable band gap (2.1eV) to absorb visible light and showed effective photoelectrocatalytic activity generating reactive oxidative species(ROS) including superoxide ion(O2·-) and hydroxyl radical(OH·). We demonstrated that when applying a bias and LED to the hematite photoanode, it exhibited effective inhibitory effect on $A\beta$ aggregation owing to hole-derived radical, OH·. Modification of hematite photoanode using co-catalyst, Co-Pi, accelerated the production of OH· and inhibitory effect on $A\beta$ aggregation. Moreover, the hematite photoanode is not only biocompatible, but also effective in suppressing $A\beta-induced$ cytotoxicity. This work gives hints to the potential of utilizing the visible light-active hematite photoanode as an inhibitor of $A\beta$ aggregation for treatment of AD in the future.