用于连续监测汗液中重金属的穿戴式超声电化学传感器研究

Environmental pollution insensibly causes the accumulation of heavy metal toxins in human body. Their overloading can cause diseases such as cancers. Wearable electrochemical sensor shows the potential to monitor heavy metals in sweat in real-time, continuously and noninvasively, which will benefit the predictable management of human health. Current wearable electrochemical sensors suffer from the electrode biofouling and low sensitivity. In this project, we propose to modify the Au electrode surface with Au nanoparticles and combine wearable electrochemical sensors with miniaturized ultrasound transducer (MEMS ultrasound). MEMS ultrasound in-situ removes the bio-molecules adsorbed on the electrode surface. Nanoparticles as well as ultrasound stirring synergistically improve the sensor’s detection sensitivity towards microvolume sweat samples. To avoid the exfoliation of nanoparticles from the electrode surface, the Au nanoparticles will be attached on the electrode surface through Au-Au metal bond and Au-SH chemical bonds. We will systematically study the correlation between MEMS ultrasound force and nanoparticle/electrode adhesion and the influence of ultrasound frequency, density towards biofouling on the electrode surface. Reconciling the strong attachment of nanoparticles and complete removal of biofouling on the electrode surface, in the end, we will develop a continuous, noninvasive, reliable, and highly sensitive strategy for monitoring heavy metals in human sweat. This research will build up new avenues for the research and development of wearable sweat sensors.

环境污染导致重金属毒素在体内悄无声息地堆积，当达到一定含量时会诱发癌症等疾病，穿戴式电化学传感器有望实时连续无创地检测汗液中的重金属，利于人们管理自身健康。现阶段穿戴式电化学传感器检测汗液中重金属面临的瓶颈是电极表面结垢和检测灵敏度低。本项目提出利用Au纳米粒子修饰Au薄膜电极，将微型超声换能器（MEMS超声）和穿戴式电化学传感器结合，通过MEMS超声原位剥离电极表面的生物污垢，协同纳米材料和超声搅拌提高传感器对微量样品的检测灵敏度。为防止超声导致纳米粒子脱落，本项目将以Au-Au键和Au-SH键的方式在电极表面修饰纳米粒子，研究MEMS超声作用力与纳米粒子/电极界面结合力的关系，考察超声频率、强度对电极表面污垢的清除规律，开发纳米粒子能稳定附着的修饰方法和表面污垢能完全清除的超声处理方案，实现单一传感器多次可靠灵敏检测汗液中重金属Cd、Pb和Hg的目标，为穿戴式汗液传感器研发提供新思路。

可穿戴汗液传感器是近些年来个人健康监测领域研究的重点。由于现阶段环境污染导致重金属毒素在人体内逐渐堆积，甚至达到一定含量时会诱发癌症等疾病，可期望利用穿戴式汗液电化学传感器实时、连续、无创地检测汗液中的重金属，利于人们深入了解自身健康状况并及时进行管理。现阶段可穿戴汗液电化学传感器检测重金属离子主要受限于电极表面结垢和检测灵敏度低两大主要问题。本课题针对上述问题展开研究,通过研究微型超声器件本身的性能特点出发，探索不同频率、不同结构的超声器件在发出的声学力的异同点；此外通过Au纳米粒子修饰Au薄膜电极提高传感器自身检测性能，并探究电化学传感器在汗液中的污染机制及汗液速率检测，最终研发出耦合微型超声器件和电化学传感器的自动化重金属离子检测系统。该系统通过将数字微流控与电化学传感器集成，实现对重金属离子浓度的准确测量以及废物移除的连续操作；通过超声器件与电化学传感器的集成，大幅增强目标物质向电化学传感器表面的质量传输，实现电化学传感灵敏度呈数量级的提高；针对实际汗液样品检测中传感器的钝化现象，利用固态装配型谐振器原位祛除污垢层，几乎能够完全恢复传感器的电化学活性，并实现连续多次稳定的检测。该课题助力我们探索可持续穿戴式汗液传感器系统，为实现单一传感器多次可靠灵敏检测汗液中重金属的目标奠定了坚实的基础，为穿戴式汗液电化学传感器研究领域提供新思路。