The authors describe a way to accumulate single superparamagnetic iron
oxide (SPIO) nanoparticles (NP) at tumor sites. Silanization coating
chemistry was performed on the SPIO which increased the NP size from 8
nm to 87 nm and also left mercapto and amino groups on the surface.
Next, they attached fluorophores and RGD on the surface for imaging and
tumor angiogenesis marker targeting. They were able to target tumor
tissue by placing a Ni wire mesh over the tumor area and using a magnet
to attract the SPIO NP to the tumor site. The half-life of tumor signal
decay in vivo decreased from 6 days to .9 days when no magnetic
targeting and magnetic targeting were compared, respectively.