Brain-targeted delivery of protein using chitosan- and RVG peptide-conjugated, pluronic-based nano-carrier.

Brain-targeted delivery of drug or imaging agent is hard to achieve efficiently due to the infiltrative nature of the blood-brain barrier (BBB). Moreover, delivery of therapeutic proteins to brain tissue is further limited by the size and physic-chemical properties of proteins. In this work, we developed a chitosan-conjugated Pluronic-based nano-carrier with a specific target peptide for the brain (rabies virus glycoprotein; RVG29) and applied for the protein delivery to the brain. The in-vivo brain accumulation of the nano-carrier in mice followed i.v injection was optically monitored with Cy5.5-conjugation to the nano-carrier, and the result showed that the Pluronic-based nano-carrier conjugated with both chitosan and the peptide was very efficient for the accumulation in brain tissue and was remarkably better than the nano-carrier conjugated with the peptide only. β-galactosidase, a model protein, was also delivered and accumulated efficiently in the brain by loading in the nano-carrier, analyzed by the bio-distribution of β-galactosidase. The delivered protein in the brain also maintained its bioactivity. Therefore, RVG29- and chitosan-conjugated Pluronic-based nano-carrier could be potentially useful for the diagnosis and therapy of brain diseases.