The targeting of endothelial progenitor cells to a specific location within a microfluidic channel using magnetic nanoparticles.

A common problem with the in vivo therapeutic applications of cells is that cells can rapidly disappear into the circulatory system after an injection. Magnetic nanoparticles can be used to solve this problem. Bacterial magnetic nanoparticles were used in this study for targeting stem cells at a specific location within a microfluidic channel. Magnetic nanoparticles were isolated from Magnetospirillum sp. AMB-1 and delivered to endothelial progenitor cells (EPCs). Cellular uptake of magnetic nanoparticles and their functional feasibility was characterized in vitro. The environment of a human blood vessel was simulated using a microfluidic channel. Magnetic nanoparticle-incorporated EPCs were injected into a microchannel and the flow rate of cells was uniformly controlled by use of a syringe pump. EPCs were effectively targeted to a specific location within the microchannel by an external magnetic field (about 400 mT). About 40% of EPCs were efficiently targeted with a flow rate of 5 microl min(-1) when 10 microg of magnetic nanoparticles were used per 10(4) cells. This microfluidic system provides a useful tool towards a better understanding of the behavior of magnetic nanoparticle-incorporated cells within the human circulatory system for clinical use.