Three Kinds Of Magnetic Nanoparticles As MRI Contrast Agent Exploration Research

Objective To prepare the different coating material superparamagneticiron oxide nanoparticles(SPIOs):sodium oleate-SPIOs、chitosan-SPIOs anddextran-SPIOs, and characterization. Investigate their invivo toxicity andassessment its effect as a contrast agent for magnetic resonance imaging, inorder to further optimize MRI contrast agent formula provides theexperimental basis.Methods The SPIOs were prepared by coprecipitation and theirproperties were measured. By dynamic light scattering, transmissionelectron microscopy and vibration magnetometer, observation their particlesize distribution on the morphology structure and magnetic propertiescharacterization.Seventy two SD rats were divided into fourgroups,including control group, sodium oleate-SPIOs group、chitosan-SPIOs group and dextran-SPIOs. The SPIOs solution was injectedvia the tail vein at a dose of100μmol/kg after anesthetized by10%chloralhydrate. Six rats of each group were killed at1days、3days and14daysafter exposure. The blood biochemical indicators of liver and kidney function were analyzed with an automatic biochemical analyzer.32SD ratswere randomly divided into the four groups, The SPIOs solution wasinjected via the tail vein after baseline imaging with a1.5T GE MRI and3.0inches coil at different times(10min、30min、60min、3h、6h). Using aSE T2map、FRFSE T2WI sequence. The relaxation times for three differentSPIOs concentrations were measured and the influence of T2values atdifferent time points through the student t test.Results We successful preparation of sodium oleate-SPIOs, chitosan-SPIOs and dextran-SPIOs. Dynamic light scattering and TEM show thatFe3O4nanoparticles uniformity is good, all is ranged from10-20nm sizeclass of spherical crystal.Vibration magnetometer testing results show thatthe SPIOs have super paramagnetic nature. The normal situation of ratswere good and no rats died, only sodium oleate SPIOs group TP content in1day and day14ALP content is higher than the control group, the othermajor blood biochemical indexes in each experimental group comparedwith control group no statistical difference (P>0.05). The SPIOs solutionwas injected via the tail vein after10min MRI scans showed that threedifferent modified materials of SPIOs can significantly reduce the liversignal, but chitosan-SPIOs reduce the liver signal more obvious. The SPIOssolution of the same concentration of three kinds of similar size differentdecoration material was injected via the tail vein after MRI enhancementscanning, all of them can shorten T2relaxation time, different time points after T2values to reduce, chitosan group decreased fastest, about30min ofreach the lowest peak. There are no difference between the three groups ofpeak, chitosan group and dextran group’s T2values rise significantly about6h, and sodium oleate group’s T2values are rising but has significantdifference with the other two groups. Shorten the T2relaxation time eachgroup and the control group has significant difference(P<0.05）. Contrastdifferences between groups in terms of tmax and clearance has significantmeaning(P<0.05）.Conclusions Sodium oleate, chitosan and dextran modified Fe3O4nanoparticles have superparamagnetism.Three groups SPIOs have lesscytotoxicity to the rat. Three kinds of modified materials SPIOs can shortenT2relaxation time and cause the change of the magnetic resonance signal.But chitosan-SPIOs reduce the liver signal more obvious and it has shortesttime to the T2value tmax and in vivo clearance rate, etc. Chitosan isconsidered to be a better surface modification of materials.