Time-varied magnetic field enhances transport of magnetic nanoparticles in viscous gel

Aim: The potential of magnetic nanoparticles (MNPs) to deliver various forms of therapy has not been fully realized, in part due to difficulties in transporting the carriers through soft tissue to different target sites. The aim of this study was to demonstrate that transport of MNPs through a viscous gel can be controlled by a combined AC (time-varying) magnetic field and static field gradient. Materials & methods: MNP velocity and transport efficiency were measured in a viscous gel at various settings of magnetic field and magnetite loadings. Results: Combined application of an AC magnetic field with the static field gradient resulted in a nearly 30-fold increase in MNP transport efficiency in viscous gel for 30% (w/w) magnetite-loaded particles as compared with static field conditions. Conclusion: The 'oscillating' effect of an AC magnetic field greatly improves the ability to transport MNPs within soft media by decreasing the effective viscosity of the gel.