功能化磁纳米颗粒检测体液中游离DNA的方法建立及临床应用研究

Cell free DNA is partially degraded endogenous DNA, which is released by tumor cells or apoptotic cells into the body fluid and dissociates from extracellular. Currently, cell free DNA can be used as a non-invasive biomarker for tumor early diagnosis, evaluation of tumor progression, and prenatal diagnosis. However, the available methods of cell free DNA detection are far from enough for clinical applicability and sensitivity and patient coverage. This issue focuses on the detection of cell free DNA in body fluids (mainly blood and urine), based on the characteristics of negative charge and restrictive molecular weight of cell free DNA, we look forward to construct DNA-based linear magnetic nanoparticles, macromolecular proteins exclusion type magnetic nanoparticles and reversed micelles-supramolecular solvent combined magnetic nanoparticles, in order to enrich and separate cell free DNA quickly, efficiently and at a low-cost in body fluids.

体液中游离DNA是由肿瘤细胞或凋亡细胞释放进入体液中，游离于细胞外的发生部分降解的内源性DNA。目前，游离DNA可以作为肿瘤早期诊断、肿瘤进行性评估和产前诊断的非侵入性评估的生物标志物，但是现有的游离DNA检测方法对于临床适用性和灵敏度及患者覆盖率远远不够。本课题关注体液（主要是血液和尿液）中游离DNA的检测，构建基于DNA的负电荷特性的DNA特异性的线型磁纳米颗粒，及构建基于游离DNA的特征性分子大小的大分子蛋白质排阻型介孔磁纳米颗粒和反相胶束超分子溶剂联合型磁纳米颗粒，以期可以迅速、高效、低成本的富集分离体液中的游离DNA。

游离DNA（ctDNA）是一种游离在体液中的DNA，已有研究表明血液和尿液中游离的DNA与某些疾病的发生发展有着密切联系。外周血中ctDNA浓度极低，血液和尿液中的蛋白质也对ctDNA提取造成一定干扰，高效、迅速、价格低廉的提取体液中ctDNA是关键。本课题成功合成了带正电荷的多氨基磁纳米颗粒，证实了对DNA有很好的萃取能力。在此基础上，合成了介孔型的多氨基磁纳米颗粒，不但增加了磁纳米颗粒表面氨基基团密度，提高了对DNA的提取能力，而且可控的介孔尺寸还能够对ctDNA有较好的提取能力。此外，本课题利用六氟异丙醇作为氢键供体，构建的低共熔试剂能够简单、快捷、高效提取血液中DNA。