Hybrid stem cell-derived bioresponsive vesicles for effective inflamed blood-brain barrier targeting delivery

Blood-brain barrier (BBB) dis-integrity, a characteristic of extensive inflammatory encephalopathy, provides the access for brain-targeted drug delivery. Inspired from the bioresponsiveness of stem cell, we conceived of new nano-scale delivery strategy via neural stem cell membrane-derived bioresponsive vesicles (NSC-Lipo) for inflamed BBB target delivery. After recombination of neural stem cell membranes with simple liposomes, the functional ligands, especially very late antigen-4 (VLA-4), were entirely engrafted into NSC-Lipo and equipped the NSC-Lipo with "pass order" to the "selective gate". It bestowed the bioresponsive vesicles with selective target the injured brain microvessel endothelial cells (BMECs) and penetrate into the lesion through the vascular cell adhesion molecule-1 (VCAM-1)/VLA-4 interaction in the post-ischemic mice model. The released anti-inflammatory agent, metformin, could reverse the inflammatory response of BMECs and rapidly recovers BBB's integrity. With the repair of BBB's integrity and down regulation of VCAM-1 expression, the targeting ability of bioresponsive vesicles cease to be in force as well. The bioresponsive vesicles led to enhanced survival rate of ischemic stroke mice (from 30 % to 90 %) after just a single injection compared to metformin loaded bare liposomes.