A Biomimetic Upconversion Nanobait-based Near Infrared Light Guided Photodynamic Therapy Alleviates Alzheimer's Disease by Inhibiting Β-Amyloid Aggregation.

Aberrant β-amyloid (Aβ) fibrillation is the key event in Alzheimer's disease (AD), the inhibition and degradation of which are recognized as a promising therapeutic strategy to alleviate the nerve damage of AD. Photodynamic therapy (PDT) holds great potential for modulation of Aβ self-assembly, which is nevertheless limited by the inefficient utilization of reactive oxygen species (ROS). Herein, we design and fabricate an erythrocyte membrane-modified core-shell upconversion nanoparticle (UCNP/Cur@EM) as a biomimetic nanobait to improve the PDT efficiency in AD. The upconversion nanoparticle with the outlayer of mesoporous silica is synthesized to load a high amount of the photosensitizer (curcumin), the unique optical feature of which can trigger curcumin to generate ROS upon near-infrared light irradiation. Integration of erythrocyte membrane enables the biomimetic nanobait to attract Aβ peptides trapped in the phospholipid bilayer, restraining the growth of Aβ monomers to form aggregates and improving the utilization rate of ROS to degrade the preformed Aβ aggregates. In vivo studies demonstrate that UCNP/Cur@EM irradiated by near-infrared light enables to decrease Aβ deposits, to ameliorate memory deficits and to rescue cognitive functions in the APP/PS1 transgenic mouse model. A biocompatible and controllable way is provided here to inhibit amyloid protein-associated pathological process of AD. This article is protected by copyright. All rights reserved.