Next-Generation Drug Delivery for Neurotherapeutics: The Promise of Stimuli-Triggered Nanocarriers.

Nanotherapeutics have emerged as novel unparalleled drug delivery systems (DDSs) for the treatment of neurodegenerative disorders. By applying different technological approaches, nanoparticles can be engineered to possess different functionalities. In recent years, the developed, stimuli-responsive nanocarriers stand out as novel complex DDSs ensuring selective and specific drug delivery in response to different endogenous and exogenous stimuli. Due to the multifaceted pathophysiology of the nervous system, a major challenge in modern neuropharmacology is the development of effective therapies ensuring high efficacy and low toxicity. Functionalization of the nanocarriers to react to specific microenvironmental changes in the nervous system tissues or external stimulations significantly enhances the efficacy of drug delivery. This review discusses the microenvironmental characteristics of some common neurological diseases in-depth and provides a comprehensive overview on the progress of the development of exogenous and endogenous stimuli-sensitive nanocarriers for the treatment of Alzheimer's and Parkinson's disease.