新型特异性寡核苷酸-靶效应DNA水凝胶对饮用水中痕量Pb2+、Hg2+的净化机制研究

Long exposure to the trace heavy metals in water, especially lead and mercury, can result to serious health hazards with the accumulation and biomagnification. The aim of the project is to develop a novel target effect DNA hydrogel based on the specific oligonucleotide technique (MSO-DNA Gel) to selectively and sensitively absorb the trace Pb2+ and Hg2+ in water for efficient water purification. This work mainly involves that, Synthesis and optimization of the MSO-DNA Gel including the stability of the DNA nanostructure unit and the activity of the target gene sequence, and their influences on the efficiency of the DNA Gel, and the performance indexes of the system of the target gene sequence-coordination chemistry-DNA Gel, the purification efficiency and dynamic characteristics of the MSO-DNA Gel in specifically removal of Pb2+ and Hg2+ in water, the effect of the water quality to the MSO-DNA Gel in specifically removal of Pb2+ and Hg2+ in water and the mechanism of regeneration of the DNA Gel. In addition, according to the coexistence of multiple heavy metal ions and organics in water and the requirements of high selectivity and sensitivity of an absorbent for the trace level heavy metal ions in water, several key scientific issues such as the design, optimization and regeneration of the MSO-DNA Gel, which could influence the efficiency of the DNA Gel, will be deeply studied. It will provide a novel concept and technique and theoretical foundation for research and development of the deep purification of the trace heavy metal in the water.

长期暴露于饮用水中痕量的铅、汞也会对人体健康造成严重危害，近年来研究多集中于新型纳米生物分子材料的研究，但利用DNA水凝胶（DNA Gel）吸附研究的报道并不多见，而重金属特异性寡核苷酸DNA水凝胶（MSO-DNA Gel）尚未见报道，且其对饮用水中痕量Pb2+、Hg2+的净化机制也不明确，本研究拟采用凝胶电泳、圆二色谱、流变学、原子荧光等手段，尝试MSO特异性捕获Pb2+、Hg2+的同时生成DNA Gel，达到选择性去除Pb2+、Hg2+的目的，考察MSO-DNA Gel体系设计、优化、再生等关键问题，探寻其净化机制，以期获得一种高效去除水中Pb2+、Hg2+的水质深度净化方法。主要内容包括： MSO-DNA Gel合成与优化； MSO-DNA Gel选择性去除水中Pb2+、Hg2+的效能及动力学特征研究；水质对MSO-DNA Gel去除Pb2+、Hg2+的影响及再生机制研究。

开发特异性寡核苷酸-靶效应DNA水凝胶是一种集水中痕量重金属去除和重金属识别为一体的新型水质净化技术。以DNA为骨架的水凝胶净化饮用水技术具有更环保、安全的特点。研究以构建可选择性去除水中痕量Pb2+、Hg2+的DNA水凝胶为目标，设计含有可特异性结合目标金属离子的寡核苷酸序列作为黏性末端的DNA单链，基于Watson-Crick碱基配对形成Y型DNA单体，再进一步捕获重金属离子并通过碱基错配协调化学机制形成DNA水凝胶，通过分析重金属的含量变化以及水凝胶的主要特性参数，确定DNA水凝胶对重金属的净化机制。.以构建高效的特异性寡核苷酸-靶效应DNA水凝胶并明确其作用机制为目标，系统考察了含有不同特异性碱基序列的DNA单链组合在Y型DNA单体-DNA水凝胶形成过程中的功能性和稳定性，明确了3DNA单链组为最佳的DNA水凝胶构成单元体系。基于对重金属的去除效果，量化了黏性末端上特异性碱基序列与重金属去除效率的关联，明确特异性碱基序列长度对目标重金属的去除作用以及对DNA水凝胶形成的影响，阐明特异性寡核苷酸-靶效应DNA水凝胶的形成机制进而明确对其的调控机制。.围绕DNA的功能作用，通过利用DNA在不同介质表面上的电化学响应强弱程度考察DNA的电化学稳定性和生物活性，分析影响DNA功能性的主导因素（比表面积、生物亲和性、惰性材料），进而有效调控DNA与介质材料结合作用效率和应用效果。并利用传感器方法具体考察了Pb2+-反式裂解8-17 DNA酶的二级结构、Hg2+-富含胸腺嘧啶的寡核苷酸的特异性性能，明确了特异性寡核苷酸在多种环境水样下均能保持正常的活性功能，并且对痕量重金属具有极其灵敏的响应能力，可适用于构建特异性DNA水凝胶。