手性单壁碳纳米管近红外荧光探针的构建及其在生物标志物检测中的应用

Single-wall carbon nanotubes (SWCNTs) intrinsically fluoresce in near-infrared (NIR) region. This unique property makes it possible to use them as NIR fluorescent probes. The label-free NIR fluorescent probes allow for direct detection of biomarkers without the need of adding extra tagging molecules and also reduce the possible autofluorescent affection from background in tissue or biological fluids at UV or visible wavelengths. The reported SWCNTs fluorescent probes were mainly constructed based on as-synthesized or enriched carbon nanotubes. The reduced fluorescence intensities of the probes affected by the interactions between tubes made the probes less sensitive and limited their further applications...In this project, a separation method considering aqueous two-phase partition and high speed countercurrent chromatography will be developed to fractionate different single-chiral SWCNTs. The NIR fluorescent probes with high selectivity are prepared based on the fluorescent properties of the chiral SWCNTs and their discriminatively binding abilities with functional molecules. Different molecules including aromatic boronic acids, xanthine oxidase, and single strand DNA are selected to non-convalently functionalize the separated single-chiral SWCNTs as NIR fluorescent probes. Then, typical biomarkers such as glucose, xanthine, and hydrogen sulfide will be set as models. The intensity variation of the fluorescent probes changed by biomarkers make the quickly quantitative determinations of these biomarkers happen. The proposed separation method of chiral SWCNTs advances in simplicity and effectiveness. The constructed NIR fluorescent probes are characterized with high fluorescent intensity and can avoid the interference from autofluorescent background in tissue or biological fluids. The proposed strategy of how to construct NIR fluorescent probes based on single-chiral SWCNTs will be potential for quickly and sensitively quantitative determination of target biomarkers.

单壁碳纳米管在近红外光谱区有较强荧光信号，可避免生物基底对紫外可见区荧光检测的干扰及检测中繁琐的标记步骤，非常适合生物标志物检测。已有单壁碳纳米管荧光探针以生长混合物或粗分离物为基础构建，不同手性碳管间的相互作用易使荧光信号减弱或淬灭，测定灵敏度低，限制其在生物标志物检测中的应用。本课题采用双水相高速逆流色谱技术，分离得到多种单一手性单壁碳纳米管。利用不同种手性体的荧光特性及其与修饰分子结合能力的差异，构建高选择性近红外荧光探针。以芳香取代硼酸、黄嘌呤氧化酶和单链DNA等构建非共价修饰探针，选取典型生物标志物，如葡萄糖、黄嘌呤、硫化氢等，根据测定前后探针荧光信号的变化实现标志物的快速检测。所建立的手性单壁碳纳米管分离方法简便高效，构建的近红外荧光探针荧光信号强，抗生物基底干扰。本课题提出的以单一手性单壁碳纳米管构建近红外荧光探针的研究思路可为生物标志物的快速灵敏检测提供一种新的方法和技术。

单壁碳纳米管（SWCNTs）在近红外光谱区有较强荧光信号，可避免生物基底对紫外可见区荧光检测的干扰及检测中繁琐的标记步骤，非常适合生物标志物检测。已有单壁碳纳米管荧光探针以生长混合物或粗分离物为基础构建，不同手性碳管间的相互作用易使荧光信号减弱或淬灭，测定灵敏度低，限制其在生物标志物检测中的应用。单一手性SWCNTs是构建荧光探针和检测功能得以实现的物质基础，如何高效地从生长产物中分离得到手性体已成为研究顺利进行的瓶颈之一。. 本课题首先建立了单一手性SWCNTs的分离方法，该方法以聚合物双水相系统为基础，通过添加合适浓度表面活性剂、盐和酸，使具有不同手性结构的SWCNTs在两相间逐步分配，以此达到单一手性SWCNTs的分离。之后，以分离所得的单一手性（6，5）SWCNT为基础材料，将苯硼酸衍生物、葡萄糖氧化酶、卡那霉素适配体、单链DNA等分子非共价修饰至SWCNT表面，构建了近红外荧光探针。并对葡萄糖、过氧化氢、多巴胺、核黄素、卡那霉素以及活性氧（氮）等生物标志物分子进行了检测。所构建的近红外荧光探针检测方法具有灵敏、快速、抗干扰的特点。本课题所建立的检测方法有望为典型生物标志物的检测提供一种新的解决思路。. 最后，本课题还采用分离所得单一手性（6,5）SWCNT搭载了紫杉醇、胆酸和盐酸阿霉素等药物，制备了药物与SWCNT的复合物，并研究了复合物对于肿瘤细胞的抑制作用。结果表明与单一手性（6,5）SWCNT形成的复合物具有比药物更强的肿瘤细胞抑制作用。该方法有望为SWCNTs负载药物提供新的研究思路。