Nanozyme-based strategies for efficient theranostics of brain diseases

Oxidative stress emerges as a critical mechanism underlying the development and progression of various brain diseases, arising from either increased generation of reactive oxygen species (ROS) or dysfunction of the antioxidant defense system. Nanozymes, possessing enzymatic catalytic capabilities alongside the physicochemical characteristics of nanosized materials, have showcased extraordinary promise in regulating the production or scavenging of ROS. Consequently, nanozymes have been utilized to detect the basic level and dynamic changes of neurochemical biomarkers closely related to physiological and pathological brain conditions, as well as to mitigate oxidative damage and facilitate the penetration of the blood-brain barrier. As such, nanozymes have emerged as a promising tool for developing diagnostic and therapeutic approaches for various neurological disorders. This review offers a comprehensive overview of the catalytic mechanisms exhibited by nanozymes, which have demonstrated tremendous potential in the effective diagnosis and treatment of brain disorders. Through summarizing the emerging methods for applying nanozymes, this review aims to provide directions on the rational design of nanozymes for the theranostics of brain diseases. Additionally, this review seeks to address the current challenges and delineate future directions for the advancement of this field.