改性墨鱼黑色素的制备及体外磁共振成像性能

Preparation and in vitro magnetic resonance imaging performance of modified cuttlefish melanin

从新鲜墨鱼的墨囊中提取黑色素(MNP),对其进行PEG官能化并加载过量Mn^2+,制备一种水溶性磁共振成像(MRI)对比剂MNP-PEG-Mn纳米粒。采用透射电子显微镜(TEM)和马尔文粒度分析仪对MNP-PEG-Mn纳米粒的形貌、粒径以及zeta电位进行表征,并进一步通过cell counting kit-8(CCK8)检测法测试其细胞毒性,最后进行体外弛豫性能测试。结果表明,MNP-PEG-Mn纳米粒为分散性好的球形颗粒,粒径为240 nm左右,zeta电位为-20.2 mV;CCK8检测法数据显示Hep2细胞与MNP-PEG-Mn孵育24 h后存活率均达到80%以上,说明其没有明显的毒副作用,生物安全性好;体外MRI结果可以看出,随着Mn^2+浓度的增加,图像呈现明显的T1信号,与临床对比剂钆双胺相比,MNP-PEG-Mn纳米粒体外成像效果显著增强,其弛豫率r1达到37.09 mM^-1/s,远高于钆双胺的5.248 mM^-1/s。

Melanin(MNP) was extracted from the ink sac of fresh cuttlefish, PEG functionalized and loaded with excess Mn^2+ to prepare a water-soluble magnetic resonance imaging(MRI) contrast agent MNP-PEG-Mn nanoparticles. The morphology, particle size and zeta potential of MNP-PEG-Mn nanoparticles were characterized by transmission electron microscopy(TEM) and Malvern particle size analyzer, and further tested cytotoxicity by cell counting kit-8(CCK8), and finally conducted in vitro relaxation performance test. The results showed that the MNP-PEG-Mn nanoparticles were spherical particles with good dispersity, the particle size was about 240 nm, and the zeta potential was-20.2 mV. The data of CCK8 assay showed that the survival rate of Hep2 cells after incubation with MNP-PEG-Mn for 24 h was more than 80 %, indicating that it had no obvious side effects and had good biosafety. In vitro MRI results showed that MNP-PEG-Mn image had obvious T1 signal with the increase of Mn^2+ concentration. Compared with the clinical contrast agent gadodiamide, the imaging effect of MNP-PEG-Mn nanoparticles in vitro was significantly enhanced, and its relaxation rate r1 reached 37.09 mM^-1/s, which was much higher than gadodiamide 5.248 mM^-1/s.