锰替代型磁性铁蛋白的仿生矿化及酶学和磁学性质研究

Magnetoferritin is a core-shell type superparamagnetic nanomaterial that is produced by biomimetic method and used ferritin as the template. Magnetoferritin has the peroxidase-like catalytic activity, having great value in the biomedicine and high-sensitivity detection. Peroxidase catalytic activity directly affects the sensitivity of detection. In the past, we enhanced the peroxidase catalytic activity of magnetoferritin by increasing the size and cobalt-doped of the core. However, compared with the peroxidase applied in clinical testing, the catalytic activity of magnetoferritin is significantly lower, so the improvement of the peroxidase activity of magnetoferritin is the scientific problem needed to be solved. The project plans to prepare manganese-doped magnetoferritin (MnxFe3-xO4) through the biomimetic synthesis process, and gather the manganese-doped magnetoferritin into polymer. And then we will study the enzymatic properties of monomer and polymer of manganese-doped magnetoferritin, in order to establish a new method to improve the peroxidase activity of magnetoferritin. In addition, the comparative study of various manganese-doping and different polymerization states will provide reference for research on the magnetic properties of similar geological samples.

磁性铁蛋白是以铁蛋白为模板仿生矿化合成的一种核-壳型的超顺磁磁铁矿纳米颗粒，具有类似于过氧化物酶的催化活性，在生物医学和高灵敏度环境检测中具有重大应用价值。过氧化物酶催化活性的高低直接影响检测的灵敏度，过去通过增加磁铁矿核的粒径和掺杂钴元素，可以一定程度地增加过氧化物酶的催化活性。但是目前磁性铁蛋白的催化活性与临床应用的过氧化物酶相比还有较大差距，因此提高磁性铁蛋白的过氧化物酶活性是急需解决的科学问题。项目拟在前期磁性铁蛋白改造的基础上，仿生合成锰替代型磁性铁蛋白(MnxFe3-xO4)，并利用生物素和链霉亲和素使锰替代型磁性铁蛋白发生聚合，研究锰替代型磁性铁蛋白单体和聚合体的酶学性质，建立提高磁性铁蛋白过氧化物酶活的新方法。本研究还将结合磁学测量，研究锰元素掺入以及分散和聚集状态下磁铁矿磁学性质的变化，为地质样品的磁性分析提供参考。

本项目利用基因工程技术改造铁蛋白外壳，融合生物素受体肽，借助宿主菌自主修饰生物素；融合Protein A结合抗体的结构域，使铁蛋白具备结合抗体的能力。利用修饰改造后的铁蛋白仿生矿化合成掺锰的新型多功能纳米材料，既具备较高的类过氧化物酶催化活性，又能结合抗体，成为自带显色标记的抗体展示平台，在免疫组化应用中展现出了替代酶标二抗的应用潜力，简化了免疫组化步骤，提高了实验效率。本项目还系统研究了趋磁细菌磁小体的磁热规律及产热机制。揭示趋磁细菌主要遵循磁滞产热机制，其卓越的磁热效能得益于磁小体的链状排列结构。