Targeting the Blood-Brain Barrier with Nano-Biomaterials

The blood-brain barrier (BBB) is the most selective and dynamic boundary that controls the exchange and transfer of molecules between blood circulation and the central nervous system (CNS). The main function of BBB is to shield the brain against substances that could be toxic; however, it also makes it difficult to deliver therapeutic medicines to treat neurological problems. Recent advancements in biomedical nanotechnology have shown great promise to overcome BBB through various mechanisms, including passive diffusion, receptor-mediated transcytosis, adsorptive-mediated transcytosis, and delivery of the drugs into the brain by crossing the BBB and facilitating targeted delivery. Small molecules, nucleic acids, proteins, and even gene-editing tools can now be delivered to parts of the CNS through nanomaterial-based techniques that were previously inaccessible. Various nanoparticle systems like polymeric (Poly(lactic-co-glycolic acid); Poly(butyl cyanoacrylate)), liposomes, cyclodextrins, dendrimers, quantum dots, and nanogels have shown encouraging outcomes in the detection and management of brain tumors, neurocognitive and degenerative disorders, including their diagnosis. The functionalities like surfactants (Polysorbate-80), proteins, and antibodies attached to the nanoparticle surfaces further enhance the BBB traversing by increased circulation time and by interacting with receptors of endothelial cells in the brain. The current chapter reviews the physiology of BBB, nano-biomaterials, and recent developments in the brain-targeted delivery of drugs through BBB and their clinical status. Better awareness of BBB trafficking mechanisms, long-term toxicity assessments, robust clinical evaluation, and regulatory considerations are current challenges in the field. With the potential to revolutionize brain therapy strategies and enhance the quality of life for patients with CNS illnesses, nano-biomaterials offer a promising direction for targeted drug delivery across the BBB.