Applications of Nanotechnology in the Diagnosis and Therapy of Stroke.

Stroke is a leading cause of death and disability worldwide. The classification of stroke subtypes is difficult but critical for the prediction of clinical course and patient management, and limited treatment options are available. There is an urgent need for improvements in both diagnosis and therapy. Strokes have rapidly evolving phases of damage involving unique compartments of the brain, which imposes severe limitations for current diagnostic and treatment procedures. The rapid development of nanotechnology in other areas of modern medicine has ignited a widespread interest in its potential for the field of stroke. An important feature of nanoparticles is the relative ease in which their structures and surface chemistries can be modified for specific and potentially multiple, simultaneous purposes. Nanoparticles can be synthesized to carry and deliver therapeutics to specific cellular or subcellular compartments; they can be engineered to provide enhanced contrast for imaging based on the detection of changes in the blood flow; or possess ligand-specific chemistries which can facilitate diagnosis and monitor the treatment response. More specifically for a stroke, nanoparticles can be engineered to release their payload in response to the distinct extracellular processes occurring around the clot and in the ischemic penumbra, as well as aid in the detection of pathological hallmarks present at various stages of stroke progression. These capacities allow targeted release of disease-modifying agents in the affected brain tissue, increasing treatment efficacy, and limiting unwanted side effects. While nanospheres, liposomes, and mesoporous nanostructures all emerge as future prospects for stroke treatment and diagnosis, much of this potential is yet to be clinically realized. This review outlines aspects of nanotechnology identified as having potential to revolutionize the field of stroke.