Compositions comprising microalgal
extracellular vesicles (MEVs) formulated for intranasal delivery are provided, whereby upon intranasal administration, the MEVs are transported by a specific
route, to specific regions in the brain via the olfactory nerve after intranasal administration, and to interconnected brain regions through the lateral olfactory tract (LOT). The MEVs are transported via neuronal axonal transport. The MEVs have the ability to cross synapses including: (i) synapses between olfactory sensory neurons (OSNs) and mitral / tufted neurons; (ii) synapses between mitral / tufted neurons and local neurons in multiple brain regions colonized by the lateral olfactory tract (LOT); and (iii) synapses between neurons in brain regions colonized by the LOT and neurons from the frontal cortex,
hippocampus,
thalamus, and
hypothalamus. The compositions contain
extracellular vesicles (MEVs) from microalgae loaded with bioactive cargo for the treatment, detection, diagnosis, or monitoring of diseases, disorders, or conditions of or involving the brain, particularly neuronal delivery of the cargo. The compositions and methods have
multiple applications as therapeutic and diagnostic agents for the treatment, diagnosis, and monitoring of diseases, disorders, or conditions of or involving the brain. The compositions can be used in methods and uses for the treatment of cancers involving the brain, and can be used, for example, to deliver therapeutic agents for psychiatric diseases, disorders, conditions, and to deliver therapeutic agents for neurodegenerative diseases, disorders, and conditions.