黑色素-纳米硒的制备及其性质

以黑芝麻黑色素为模板剂和还原剂制备黑色素-纳米硒，对黑色素-纳米硒的制备工艺进行优化，并表征其结构和形貌，之后进一步探讨其缓释特性、体外抗氧化能力，评价其对红细胞和内皮细胞EAhy926氧化损伤的保护作用，通过肺癌细胞A549模型和海虾致死实验探讨其抑癌活性和生物相容性。结果表明黑色素-纳米硒合成的最适条件为：0.3 mg/mL黑色素溶液与0.555 mg/mL二氧化硒溶液体积比为9∶5，反应pH 7,40℃避光磁力搅拌(400 r/min)反应5 h。X射线光电子能谱结果表明Se⁴⁺可被全部还原。红外结果表明黑色素结构中羧基及共轭结构可能参与了反应。同步光散射仪表征黑色素-纳米硒粒径约为200 nm，性质稳定，能较好地分布于水分散体系中。黑色素-纳米硒在人工模拟胃液环境中可稳定存在2 h，具有一定的pH值稳定性，在人工模拟肠液环境中可缓慢释放，能实现在肠液中的长效缓释。体外抗氧化结果表明黑色素-纳米硒对2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除率和总还原力显著优于二氧化硒。黑色素-纳米硒能显著抑制H₂O₂

Preparation and Properties of Melanin-Nanoselenium Complex

In this work, black sesame melanin was used as template and reducing agent to prepare a melanin-nanoselenium complex. The preparation process was optimized, and its structure and morphology were characterized. Also, its antioxidant capacity in vitro was tested, and its protective effect on oxidative damage of red blood cells and EAhy926 endothelial cells was evaluated. Its anticancer activity and biocompatibility were investigated by using lung cancer cell line A549 and shrimp killing experiment. The results showed that the optimum conditions for the synthesis of melanin-nanoselenium complex were as follows: volume ratio of melanin solution (0.3 mg/mL) to selenium dioxide solution (0.555 mg/mL) 9:5, pH 7, and reaction time 5 h with magnetic stirring (400 r/min). The results of X-ray photoelectron spectroscopy (XPS) showed that Se4+ was completely reduced. The results of infrared (IR) spectroscopy indicated that the carboxyl and conjugate structures of melanin might be involved in the reaction. According to the results of characterization by synchronous light scattering, the particle size of the melanin-nanoselenium complex was approximately 200 nm, and it was stable and could be well distributed in water dispersion system. The complex remained stable for 2 h in simulated gastric juice, and was pH tolerant. It could be released slowly in simulated intestinal juice, thus having the potential for long-term sustained release. In vitro antioxidant results showed that the scavenging capacity against 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation and total reducing power of the complex were significantly better than those of selenium dioxide. The complex significantly inhibited hemolysis of red blood cells and oxidative damage of EAhy926 endothelial cells induced by hydrogen peroxide, and had inhibitory activity on lung cancer cells. The toxicity of this complex was weaker than that of selenium dioxide, whose semi-lethal concentration (LC50) values were 347.393 and 19.781 µg/mL, respectively. This study is meaningful for guiding further research on melanin resources and the preparation of melanin-nanoselenium complex, and also provides a theoretical basis for the use of melanin-nanoselenium complex as a dietary selenium supplement.