Catalytic DNA Biosensor for Toxic Metal Ions

描述(由申请人提供)：将探索一种开发催化DNA生物传感器的一般方法，用于现场、实时和经济有效地同时检测和定量多种重金属离子，如汞、镉和铅。接触这些金属离子会给人类带来严重的健康影响，如对大脑和肾脏的损害，以及癌症。它们还可能对儿童的神经和大脑发育造成不利影响，对儿童的影响往往是不可逆转的。因此，迫切需要用于这些金属离子的便携式传感器，用于家庭、农村或偏远地区的临床应用，以及反恐战争中的第一反应人员，其中现场、实时和具有成本效益的检测和量化至关重要。这一第一阶段的应用解决了如何将一种成功的方法设计用于一种金属离子的传感器应用于其他金属离子的传感器，以及如何提高这些传感器的选择性的关键问题。它建立在PI实验室最近的一项成功的基础上，其中基于催化DMA展示了高灵敏度和选择性的铅荧光和比色传感器。在第一阶段，将研究将这一方法作为一般议定书应用于另外两种重金属，即汞和镉的可行性。具体地说，一种称为体外选择的组合生物学技术将被用于选择汞(11)和镉(11)特定的催化DMA。在采用负选择策略来提高所选DNA分子的选择性后，将构建汞和镉的荧光传感器和比色传感器，并分别将荧光团/猝灭剂和金纳米颗粒附着到催化DNA分子上进行测试。在第一阶段实现这些目标后，将在第二阶段选择针对砷和铬的催化DNA，并将开发这些重金属离子的原型传感器套件，用于测试和销售环境监测和医疗诊断应用中的传感器。

DESCRIPTION (provided by applicant): A general method of developing catalytic DNA biosensors for on-site, real-time, and cost-effective detection and quantification of multiple heavy metal ions, such as mercury, cadmium and lead, simultaneously will be explored. Exposure to these metal ions can bring severe health effects to human beings, such as damages to brain and kidneys, and cancers. They can also cause adverse effects on neural and brain development in children and the effects in children are often irreversible. Therefore there is an urgent need of portable sensors for these metal ions for household uses, for clinical applications in rural or remote areas, and for first-responders in the war against terrorism, where on-site, real-time, and cost-effective detection and quantification are critical. This Phase I application addresses critical issues of how to apply a successful method in designing sensors for one metal ion to those of other metal ions, and how to enhance selectivity of those sensors. It is built upon a recent success in the PI's lab where highly sensitive and selective fluorescent and colorimetric sensors for lead have been demonstrated based on catalytic DMA. In phase I, the feasibility of applying this method as the general protocol to the two other heavy metals, namely mercury and cadmium, will be investigated. Specifically, a combinatorial biology technique called in vitro selection will be carried out to select Hg(ll)- and Cd(ll)-specific catalytic DMA. After negative selection strategies are used to improve the selectivity of the selected DNA molecules, fluorescent and colorimetric sensors for mercury and cadmium will be constructed and tested by attaching fluorophore/quencher and gold nanoparticles, respectively, to the catalytic DNA molecules. After achieving these goals in Phase I, catalytic DNA specific for arsenic and chromium will be selected in Phase II and the prototype sensor kits for these heavy metal ions will be developed for testing and marketing the sensors in environmental monitoring and medical diagnostic applications.