The human brain is guarded by one of biology's most selective security systems, and it turns away nearly every large-molecule drug that tries to get in. Cracking the blood-brain barrier (BBB) has become one of the most competitive races in modern biotech, with the first approved transferrin-receptor "shuttle" biologic now on the market and multibillion-dollar licensing deals reshaping the field.
The blood-brain barrier is a highly selective, dynamic interface between the circulating blood and the central nervous system (CNS). It is not a single wall. It is a living, multicellular structure built into the walls of the brain's blood vessels, and it decides which nutr...
