新型仿生纳米颗粒用于体外癌症病理诊断

Cancer diagnostic reagent with high sensitivity and specificity is the key to cancer therapy and treatment successfully. We have previously reported that iron oxide nanoparticles exhibit peroxidase activity that can catalyze the oxidation of peroxidase substrates to produce a color reaction, similar to that of natural peroxidases. On the basis of these findings, we biomimetically synthesized a novel magnetoferritin nanoparticles with a iron oxide core encapsulated in a recombinant human ferritin protein shell, which can specifically target and visualize tumour tissues. The protein shell binds specifically to tumour cells, while the iron oxide core exhibits peroxidase activity that visualizes the tumours in the presence of chromogen substrates. Compared with traditional immunohistochemistry which generally involves multi-step incubation of primary antibody, secondary antibody or enzyme labeled third antibody, our novel method employs one step incubation of one reagent since it achieves tumours targeting and visualization in one step. This application intends to use this novel biomimetic nanoparticles for tumour tissues detection. We will systematically investigate the interactions between magnetoferritin nanoparticles and tumor cells, and analyze the sensitivity and specificity of tumour tissue staining. With the implementation of this project, this novel biomimetic nanoparticles have the potential to become a novel diagnostic reagent for the rapid identification of tumours with high sensitivity and specificity, which then will help improve the diagnostic level of our country and promote the integration of the fields of nanotechnology and biological medicine.

高灵敏、高特异的肿瘤诊断试剂是其治愈的关键。本实验室在发现氧化铁纳米颗粒具有类酶活性的基础上（Nature Nanotech 2007, 2:577），利用人体生物矿化原理仿生合成了一种集肿瘤特异识别与显色于一体的双功能癌症诊断试剂-仿生纳米铁蛋白。这种新型仿生纳米铁蛋白由蛋白壳及氧化铁纳米内核组成。其中，蛋白壳主动靶向肿瘤细胞，能够区分正常细胞和癌细胞，氧化铁纳米内核具有类过氧化物酶催化活性，能够同辣根过氧化物酶(HRP)底物反应显色。因此，这种新诊断试剂兼肿瘤识别与显色一步完成，无需一抗、二抗或是HRP等酶或信号分子的标记，与传统的免疫组化相比，具有操作简单、经济、灵敏度高的特点。本项目将在分子、细胞、组织及临床等多个层面全面评价其用于癌症病理诊断的可行性；揭示其肿瘤主动靶向机制，发现肿瘤新靶点；发展新肿瘤组织诊断技术；帮助提升我国肿瘤诊断水平，促进纳米技术和生物医药等领域的交叉融合。

高灵敏、高特异的肿瘤诊断试剂是癌症治愈的关键。本项目首次发现了人的重链H亚基铁蛋白具有天然的肿瘤识别特性，并阐明了铁蛋白与转铁蛋白受体（TfR1）介导的肿瘤识别机制，体外仿生制备了该铁蛋白纳米粒子。该纳米粒子由磁性氧化铁纳米内核及铁蛋白外壳两部分组成的双功能纳米小体，蛋白壳能够特异识别肿瘤细胞，氧化铁纳米内核能够催化氧化底物使肿瘤显色，区分正常细胞和肿瘤细胞。通过对临床1500余例的标本筛查，验证其灵敏性为95%，特异性为97%，与目前临床诊断金标准的免疫组化方法相一致。本项目基于以上研究工作开发了基于纳米铁蛋白的肿瘤病理诊断技术及试剂盒，并实现了6千万的技术成果转让，发表SCI论文3篇，申请国家发明专利4项，PCT 2项，专利授权1项，全面完成计划书规定的内容和指标。