that by 2040, neurodegenerative diseases will surpass cancer as the second reason of death after cardiovascular diseases in such aged populations. [1,2] As per a 2017 report, neurological diseases cost the United States of America about $800 billion annually and this number is expected to increase even further over the coming years as the percentage of aged citizens increases. [3] Unlike most other major diseases, the pace of drug development and delivery in case of neurodegenerative diseases has been stationary, partially due to lack of biomarkers that can diagnose such diseases long before the neurological symptoms arise and the challenges associated with identification of targets for drugs that can terminate or minimize neurodegeneration. Most importantly, delivering new cerebral therapeutic agents is impeded by the extensive and robust blood-brain barrier (BBB) which prevents the vast majority of drugs from crossing to the brain after systemic administration. During brain infections, intracerebral hemorrhage, or in neurodegenerative disorders, the BBB is altered in such a way that it allows easy access of inflammatory inducing molecules that may cause adverse neuronal damage. [4] Given the importance of early diagnosis and treatment of neurodegenerative diseases, new drug delivery technologies have appeared in the last decade.As shown in Scheme 1, unique nanomaterials have been reported and several nanosized drug delivery systems including liposomes, dendrimers, carbon nanotubes (CNTs), inorganic and hybrid nanoparticles, and polymeric micelles have gained attention and have been tested for targeted drug delivery not only for neurodegenerative diseases but also for several other ailments. [5][6][7][8][9][10] The discovery of MCM-41 was recognized as a major breakthrough in materials science and since then mesoporous silica nanoparticles (MSNs), thanks to their superior physiochemical properties such as large porosity, high surface areas, low toxicity, controllable sizes, and wide range of morphologies compared to conventional nanoparticles (NPs) have emerged as favorable tools in biomedical applications as nanocarriers for encapsulation and delivery of therapeutic medicines. [11][12][13][14] Designing biocompatible MSNs and their multifunctional derivatives for drug transport as well as theranostics is one of the hottest areas of research in the field of nanobiotechnology and nanomedicine. [15][16][17][18][19] High loading capacity, acceptable biocompatibility, and limitless possibilities of surface functionalization for specific cellular recognition Mesoporous silica nanoparticles (MSNs) have gained wide attention for their role in biomedicine and as drug delivery vehicles. Their structural tunability, high surface area, and easy functionalization impart significant advantages over conventional materials. In this Review, recent advances in the synthesis, drug delivery, and therapeutic roles of MSNs in the treatment of various neurodegenerative and neuroinflammatory diseases are presented. The intention is to...
