Surface Active Ligands for Enhanced Brain Targeting of Nanoparticles

Brain disorders such as Alzheimer’s disease, Parkinson’s disease, epilepsy, glioma, depression, and anxiety are affecting the cognitive ability, senses, memory, mood, and emotional behavior of affected people and are the second leading sources of deaths across the globe. The current treatments with the conventional delivery systems alleviate the symptoms of these disorders and fail to achieve sufficient drug concentration in the brain which ultimately limits the therapeutic efficacy due to the presence of the blood–brain barrier (BBB). Therefore, researchers are working constantly to improve the therapeutic efficacy of administered drugs by different targeting approaches. In this context, the passive targeting approach has been explored in the past few decades for brain targeting and found several limitations such as the pathophysiological condition of disease and off-targeting effects. Hence, researchers are working on an active targeting approach with the use of surface active ligands such as transferrin, lactoferrin, antibodies, aptamers, peptides, and cell-penetrating peptides for active brain targeting. The surface active ligands are attached to nanocarriers that will interact with the endothelial cells of BBB which ultimately facilitates drug transport to the brain by different physiological mechanisms. Thus, in this book chapter, the surface active ligands used for the active targeting of the brain are described briefly. Further, the studies reported by using ligand-receptor and ligand-transporter mediated transcytosis mechanisms for brain targeting using nanoparticles are discussed in detail in this compilation.