Enhanced brain retention time of MPI tracer via antibody conjugation

Abstract

Hyperthermia guided by Magnetic Particle Imaging (MPI) is an emerging technique for targeted thermal therapies, including blood–brain barrier opening and localized tumor ablation. However, this technique works best for locally injected magnetic nanoparticles, but faces limitations with intravenous administration. Floating with circulation, the tracers often traverse the target region too quickly, succumbing to heat loss by blood cooling, thus failing to achieve sufficient localized thermal doses. This limitation reduces the efficacy of MPI-guided hyperthermia for precision applications in sensitive tissues such as the brain. Here, we propose a strategy to immobilize the magnetic nanoparticles at the brain capillary level via antibody conjugation specific to the vascular endothelium allowing future localized heating experiments. We present initial experimental proof showing the feasibility of this approach by increasing retention times of particles in the brain evidenced by extended local blood half-life.