Transcranial application of magnetic pulses for improving brain drug delivery effi ciency via intranasal injection of magnetic nanoparticles

As the blood–brain barrier (BBB) hinders efficient drug delivery to the brain, drug delivery via the intranasal pathway,bypassing the BBB, has received considerable attention. However, intranasal administration still has anatomical and physiologicallimitations, necessitating further solutions to enhance effectiveness. In this study, we used transcranial magneticstimulation (TMS) on fluorescent magnetic nanoparticles (MNPs) of different sizes (50, 100, and 300 nm) to facilitateMNP’s transportation and delivery to the brain parenchyma. To validate this concept, anesthetized rats were intranasallyinjected with the MNPs, and TMS was applied to the center of the head. As the result, a two-fold increase in brain MNPdelivery was achieved using TMS compared with passive intranasal administration. In addition, histological analysis thatwas performed to investigate the safety revealed no gross or microscopic damages to major organs caused by the nanoparticles. While future studies should establish the delivery conditions in humans, we expect an easy clinical translation interms of device safety, similar to the use of conventional TMS. The strategy reported herein is the first critical step towardseffective drug transportation to the brain. KCI Citation Count: 0