Influence Of Aggregation Of Ferrofluid On Targeting Of Magnetic Drug

As an important drug carrier for magnetic drug targeting, ferrofluid could beconcentrated at a defined target site with the aid of permanent magnetic field, andreleased nanoparticle-banded drug, which enhanced drug concentration in the targetand at the same time reduced the toxicity to normal tissues. This paper focused onstudying in-vitro ferrohydrodynamics and in-vivo targeting, so as to seek after anapproach to the targeting of magnetic carriers.Based on the experiment of in vitro simulating the human circulatory, the paperstarted with the Kozeny equation, and established an improved model or so-calledpoly-microspheres model. Considering the variations in the size of one singlemicrosphere formed by nanoparticles, the proposed model improved the defects ofmono-microsphere model. Results from the poly-microspheres model could becompared with the experimental results, which demonstrated the cause of aggregationsuccessfully. From the curve of radius of microspheres, we can figure out that theradius of microspheres decreased with ferrofluid flowing close to the magnetic pole.Then applying newton law of viscosity and boundary later theory of fluids, the paperanalyzed the movement of non-uniform ferrofluid exposed to the magnetic field,through which it was concluded that non-uniformity benefited the retaining offerrofluid. According to MTT colorimetry in the experiment on in-vitro cytotoxicity, wegained two toxicity curves including B16 cell and MA891 cell, which showed that thedenser ferrofluid was, the more cytotoxicity it would produce. The experiment ofin-vivo toxicity was achieved by mensurating half lethal dose(namely LD50) offerrofluid in mice, and we got LD50=838.98mg/kg. It was shown that ferrofluid couldbe a safe drug carrier with the limitation of dosage. It also gived the reason fordetermining the dosage of later experiments. Finally we injected ferrofluid in veininto mice, and exposed the tumor site exactly to the magnetic pole for 30 minutes.Then the distribution of ferrofluid was checked by MRI. It was proved that ferrofluidor magnetoliposomes could be targeted successfully to the tumor site with the aid ofmagnetic field. All above results showed advantage evidence for extending andapplication of magnetic drug targeting.