目的:检测γ-Fe2O3纳米粒表面油酸的残留量,考察油酸残留量对纳米粒磁共振T1造影效果的影响。方法:采用热分解法制备γ-Fe2O3纳米粒,使用mPEG-P取代γ-Fe2O3纳米粒表面的油酸,得到水溶性的γ-Fe2O3-PEG纳米粒,采用高效液相色谱法测定纳米粒表面残留的油酸,并在7T磁共振成像仪下考察油酸残留量与纳米粒T1造影效果的关联。最后,对体外造影效果最优的样品进行了体内磁共振成像测试。结果:建立了油酸的高效液相色谱检测方法,油酸在10~400 μg/mL浓度范围内具有良好的线性关系(r2 = 1),平均回收率为99.86%。通过改变γ-Fe2O3与mPEG-P的投料比,得到γ-Fe2O3-PEG纳米粒表面油酸残留个数分别为100、83、56、33的样品。体外磁共振成像结果表明,油酸残留量较少的纳米粒拥有更好的T1加权成像性能。小鼠体内血管造影显示,本研究制备的γ-Fe2O3-PEG纳米粒与临床使用的钆类造影剂相比,拥有更好的血管成像效果。结论:本研究成果为热分解法制备的氧化铁纳米粒表面油酸的定量分析提供了一种有效的检测方法,以促进该类纳米粒在生物医学领域的应用。Objective: Detection of residual oleic acid on the surface of γ-Fe2O3 nanoparticles and investigation of its impact on magnetic resonance T1 imaging. Method: We prepared γ-Fe2O3 nanoparticles via thermal decomposition, with mPEG-P replacing the oleic acid on the surface of the nanoparticles to yield water-soluble γ-Fe2O3-PEG nanoparticles. The residual oleic acid on the surface of the nanoparticles was quantified using High-Performance Liquid Chromatography, and the relationship between the amount of residual oleic acid and the T1 contrast effect of the nanoparticles was investigated using a 7T magnetic resonance imaging system. Finally, the vivo magnetic resonance imaging of the sample exhibiting the optimal in vitro contrast effect was conducted. Results: We developed a High-Performance Liquid Chromatography me
