Magnetic Relaxation Imaging of Magnetic Nanoparticle Distributions

摘要

We have developed a fluxgate scanner for the two-dimensional magnetic relaxation imaging of magnetic nanoparticle distributions at the inner surface of cell culture bags for human stem cell growth. In magnetorelaxometry (MRX), the magnetic moments of superparamagnetic nanoparticles are aligned by an external magnetic field of the order of a few mT, and after switching off the magnetic field the decay of the net magnetic signal is measured. Due to their different relaxation time constants, bound and unbound nanoparticles can be distinguished without washout steps of unbound ones. In our setup, we employ a cylindrical wire-wound coil for the magnetization and a racetrack fluxgate for the detection. An x-y-table shifts the sample by maximum 200 mm in x-direction and 150 mm in y-direction with typical scan steps of 1 mm. The vertical distance of the sensor to the sample amounts to approximately 100 μm. First scanning results on especially prepared cell contact plates demonstrate the suitability of the MRX scanner for the two-dimensional characterization of functionalized surfaces.