PSI Grafted Amphiphilic Polymers Modified SPIONs MRI Contrast Agent Preparation And Characterization

Nuclear magnetic resonance imaging (MRI) has become a useful technique in clinical diagnostics. Due to their remarkable magnetic properties and low toxicity, surperparamagnetic iron oxide nanopaticles (SPIONs) are the most intensively investigated. In this paper, two novel amphiphilic polymers were successful prepared, their main chain was PSI, and modified SPIONs by self-assembly. Stable micelles were prepared and used for magnetic resonance imaging (MRI) testing.In this paper, we design and synthesis of poly (aspartic acid) (PSI) as the main chain, then introduced mPEG-Amine and poly (caprolactone) (PCL) segments for the side base of two novel amphiphilic polymers. The main contents as follows:(1) Firstly, magnetic nanoparticle core oleic acid-coated hydrophobic SPIONs were prepared by thermal decomposition of iron(III) acetylacetonate (Fe(acac)3), oleic acid and oleylamine. Then, PSI were prepared by thermal polymerization, used ethanol amine for ring-opening of PSI, then graft PCL, finally DGA was used to complete of the ring-opening. We got the amphiphilic polymer PSI-g-(PCL/DGA) links of peptide bond. Finally, the polymeric micelles PSI-g-(PCL/DGA)@Fe3O4-ol was obtained by self-assembly.The modified nanoparticles were subjected to detailed characterization using DLS, TEM measured the average particle size of the magnetic nanoparticles is 75 nm; the VSM were measured at room temperature and the saturation magnetization was 42.2 emu g'1. Cytotoxicity test (MTS) to prove that in the cell of L929 has low toxicity. The result of ICP show that its iron content is 4.91%. Through Siemen Trio TIM 3 T the transverse relaxation rate 12 was 334.0 mM-1s-1. So the nanocomposites may be used as a MRI contrast agent. By 240 min MRI tracking results, whether in KM mice heart, liver, IVC, kidney, bladder, the contrast effect is enhanced, and the observed in vivo metabolic process is slow.(2) PSI-g-(PCL/mPEG/DGA)@Fe3O4-ol micelles was prepared by self-assembly. The modified nanoparticles were subjected to detailed characterization using DLS, TEM measured the average particle size of the magnetic nanoparticles is 35 nm; the VSM were measured at room temperature and the saturation magnetization was 35.6 emu g-1. Cytotoxicity test shows that when the iron content is below 120 ?g/mL, there had no obvious effect on L929, the iron content is equal to 200 ?g/mL, the cell survival rate was 80%, it has low toxicity.The result of ICP show that its iron content is 12.5%. Through Siemen Trio TIM 3 T the transverse relaxation rate r2 was 263.0 mM-1s-1. By 240 min MRI tracking results, whether in KM mice heart, liver, IVC, kidney, bladder, the contrast effect is enhanced, and there are still increase in 240 min.(3) P(HEA-co-SI)/Fe3O4@NH2 was designed and synthesized. The modified nanoparticles were subjected to detailed characterization using DLS and its has average particle of 35 nm; And through the FT-IR, Raman characterization for its structure. The result of ICP show that its iron content is 6.2%. Through Siemen Trio TIM 3 T the transverse relaxation rate r2 was 18.2 mM-1s-1.In addition, all of the polymer above were characterized by 1H-NMR, FT-IR, GPC to subject there molecular structure, molecular weight and PDI. The modified nanoparticles were subjected to detailed characterization using DLS, TEM, XRD, VSM and MRI.