基于DNA/MoS2水凝胶及结构转换型DNA探针的有机磷阻燃剂生物标志物的荧光传感方法

Organophosphate flame retardants (OPFRs) emerging as substitutes to polybrominated diphenyl ethers have been widely used and released into the surrounding environment gradually. In addition, exposure to OPFRs may exert adverse health effects to ecological safety and human health, such as carcinogenicity, neurotoxicity and embryo toxicity. Studies showed OPFRs are readily metabolized in the body to their diester metabolites, such as BDCIPP (bis(1,3-dichloro-2-propyl) phosphate) and DPHP (diphenyl phosphate). Therefore, it is of great significance to develop a novel sensor in realizing highly selective, highly sensitive and rapid analysis for OPFRs or its derivatives. In combination with the excellent recognition ability of OPFRs metabolite binding aptarmer obtained by SELEX method, and high sensitivity of designed structure-switching signaling aptamer based on the screened binding aptarmer, we are developing a novel fluorescent sensor in realizing highly sensitive, highly selective and rapid analysis for metabolic biomarkers of OPFRs in human body. Its detecion mechanism is purposed as follows: the strong Van der Waals force between MoS2 and ssDNA(eg. aptamer or designed structure-switching signaling aptamer) can lead to the gelation of MoS2 nanosheets, thus forming the DNA/MoS2 hybrid hydrogel. After soaking in the target molecule, the interaction between the formed double-stranded DNA (dsDNA) and MoS2 is so weak that the dye-labeled probe is away from the surface of MoS2, leading to the fluorescent change in the system. The main research contents include the preparation, characterization, sensing performance and recognition optimization of DNA/MoS2 hybrid hydrogel based fluorescent biosensor, and further illustrating the relationship between the microscopic structure of the sensor, the preparation methods and the recognition performance. This research will provide a powerful technique in the detection of OPFRs derivatives and play an important role in assessing the OPFRs exposure status in human.

有机磷阻燃剂(OPFRs)在人体内的暴露水平检测备受关注。尿液中OPFRs的代谢产物BDCIPP和DPHP可作为OPFRs的生物标志物。本项目以BDCIPP或DPHP为靶分子，采用SELEX法筛选其适配体，构建包含该适配体的结构转换型DNA荧光探针，基于单链DNA与二硫化钼(MoS2)纳米片间的范德华力，以该探针为交联剂制备DNA/MoS2水凝胶，鉴于适配体对OPFRs生物标志物的特异性识别引起的DNA探针构象变化及DNA/MoS2水凝胶与单双链DNA之间范德华力的差异性，导致DNA探针荧光基团的有效释放，通过检测体系荧光强度的变化，实现OPFRs生物标志物的高灵敏、高选择性、快速检测。研究内容包括DNA/MoS2水凝胶传感器的制备表征、检测性能及识别条件优化、传感方法的检测机理。所构建的DNA/MoS2水凝胶传感器将为正确评估OPFRs在体内的暴露水平提供技术支撑。

有机磷阻燃剂(OPFRs)在人体内的暴露水平检测备受关注。尿液中OPFRs的代谢产物BDCIPP 和DPHP可作为OPFRs的生物标志物。本项目结合单层MoS2纳米材料、金属纳米粒子、壳聚糖水凝胶和生物分子识别技术，开发了一系列基于单层MoS2纳米复合材料的电化学/比色传感方法，以及基于MoS2水凝胶宏观三维结构的比色/DNA适配体荧光传感方法，实现了对目标物质的灵敏和特异性检测；采用磁珠-SELEX技术筛选了OPFRs生物标志物DPHP适配体并构建结构转换型DNA探针；鉴于适配体对目标物的特异性识别引起的DNA探针构象变化及壳聚糖-MoS2/DNA水凝胶与单双链DNA之间范德华力的差异性，导致DNA 探针荧光基团的有效释放，通过检测体系荧光强度的变化，实现靶标/生物标志物的高灵敏、高选择性、快速检测。进一步探索了开发的荧光传感方法的通用性，通过更换识别元件实现了对其他目标物的检测，提升了该方法的适用领域和实际意义。本研究结果可为污染物的高灵敏性、高特异性、快速的定量检测技术研发提供理论和技术支撑。