Stiction Mitigation of Nanoparticles in Magnetically Targeted Drug Delivery System

This article addresses the stiction issue of magnetic nanoparticles (MNPs) in a targeted drug delivery system (TDDS). In a magnetically actuated TDDS, the MNPs are guided to the desired blood vessel by steering them from the bifurcation points, using an external electromagnetic actuation (EMA) system. During the steering process, some of the MNPs get stuck to the vessel wall. To overcome this problem, an EMA system is designed using four coils and the corresponding coil parameters are computed to efficiently steer the MNPs in a Y-shaped microchannel. The proposed EMA system operates in two different modes alternately, by switching on and off a pair of coils. In the first mode, the system generates magnetic force responsible for steering the MNPs. In the second mode, it generates a small magnetic force in the reverse direction, which pulls back the MNPs stuck to the vessel walls, thus mitigating the stiction problem. The MNPs that are separated from the sidewalls move ahead with the fluid flow to the desired channel and this guidance mechanism is repeated till the MNPs reach the target point. The experimental validation of the proposed EMA system highlights its practical feasibility to mitigate the stiction issue. Results demonstrate that the magnetophoretic force produced to release the adhered particles in our system is around 99.5% lower than that of an existing EMA system, which aims to address the same issue. Thus, our system provides enhanced efficacy in mitigating the stiction issue by alleviating the detrimental effect of the MNPs getting steered to the undesired outlet.