Chemically Designed Functional Nanomicelles for Blood–Brain Barrier Crossing

The blood-brain barrier (BBB) is a specialized semipermeable structure that restricts the exchange of materials between central nervous system parenchyma and blood vessels. Nanocarriers have shown the potential to cross the BBB via receptor-mediated transcytosis (RMT) or adsorption-mediated transcytosis (AMT), though efficiency remains limited. Here, we report two different polymer nanomicelles of 20-60 nm size that efficiently cross the BBB via either RMT or AMT. We have tested their performance in a transwell-based model, tumor spheroid model, and <i>in vivo</i> mice model. We found that lower numbers of receptors per nanomicelle are critical for RMT and direct membrane penetration property of nanomicelle is critical for AMT. Transcytosis can be enhanced by 8-10 times using the optimized nanomicelles that leads to 8 times enhanced penetration in tumor spheroid and 26-35 times enhanced delivery to deep brain tissue. These polymer nanomicelles can be used as nanocarrier for <i>in vivo</i> delivery of therapeutic biomolecules in brain.