光微流回音壁微泡腔用于无标记检测水中铅离子浓度研究

In recent years, the incidents of pollution of heavy metal ion in drinking water keep occurring and threaten the health of human beings, especially children. Therefore, the method to detect the concentration of heavy metal ions in water more efficiently and quickly becomes an urgent problem to be solved. According to the major requirements for the environment, population and health by the “Outline of the National Program for Long-and Medium-Term Scientific and Technological Development”, this program is focused on studying the detection the heavy metal-lead ion concentration in aqueous solution based on optofluidic whispering-gallery-mode (WGM) microcavity. The sensitivity of the traditional optical WGM microcavity sensor is limited due to that it relies on evanescent wave outside the microcavity. While, our previous works showed that optofluidic microbubble resonator could break this limitation and obtain higher sensitivity and lower detection limit. Utilizing optofluidic microbubble resonator which possesses the natural micro fluidic channel and has characteristics of high quality factor, low mode volumes, high circulating power density, high sensitivity and low detection limit, we study on regulation and enhancement of the sensitivity in optofluidic microbubble resonator and surface modification technique to detect the lead ion concentration in aqueous solution for features of rapid, label-free, specific and real-time. This program exploits a new method to label-free detect the lead ion in aqueous solution and will provide theoretical basis and technical accumulation for the application of detecting the concentration of heavy metal ion in aqueous solution based on optofluidic microbubble resonator.

近年来，饮用水中重金属离子污染事件频发，严重威胁着人类特别是儿童的健康。因此如何能更高效、快速检测水中重金属离子的浓度成为一个亟待解决的问题。本项目根据国家中长期科学和技术发展规划纲要对环境、人口与健康提出的重大战略需求，利用光微流回音壁模式微泡腔研究水溶液中重金属-铅离子浓度超标污染的检测问题。传统光学回音壁模式微腔传感器依靠腔外倏逝波传感而导致灵敏度受到限制。前期工作表明，光微流微泡腔可以突破这一限制，从而达到更高的灵敏度和更低的探测极限。本课题利用光微流微泡腔天然的微流通道，结合其高品质因子、低模式体积、高能量密度等特点，通过研究微流微泡腔传感灵敏度调控和增强、微流腔壁表面修饰技术，完成水溶液中极低铅离子浓度的快速、无标记、特异性和实时检测。本项目开拓了无标记检测水溶液中铅离子浓度的新方法，将为发展光微流微腔在重金属离子污染检测的应用提供理论基础和技术积累。

近年来，饮用水中重金属离子污染事件频发，严重威胁着人类特别是儿童的健康。因此如何能更高效、快速检测水中重金属离子的浓度成为一个亟待解决的问题。本项目根据国家中长期科学和技术发展规划纲要对环境、人口与健康提出的重大战略需求，利用光微流回音壁模式微泡腔研究水溶液中重金属-铅离子浓度超标污染的检测问题。主要研究内容如下，通过调控微泡腔壁厚和选择性激发，模式体折射率灵敏度达265.2 nm/RIU；采用GR-5 DNAzyme来修饰微腔内壁，并结合模式自参考技术，水溶液中铅离子探测极限达到3.1 pg/L (15 fM)，这一探测极限比原申请书低3个数量级，比世卫组织要求的安全饮用水标准低6个数量级（10 μg/L）；实现了对水溶液中铅离子的快速检测，检测时间低至20 s；测试了8种竞争金属离子（钠离子、钙离子、锌离子、钾离子、铜离子、三价铁离子、二阶铁离子、锰离子），铅离子响应较其他重金属离子信号比在20：1以上，能够实现特异性检测；通过测试闽江水源保护区的河水，验证河水没有受到铅污染，展示了该传感器在饮用水铅污染监测的能力；为简化实验装置和推动传感装置便携化，实现了基于光微流微腔的荧光型铅离子传感器，该装置无需熔锥光纤耦合，全部为自由空间光路。此外，还开展了液滴型微腔传感器、开放式微盘激光化学传感器及液态金属芯光微流微腔传感平台等研究。通过本项目的实施，推动了高品质微流微泡腔在重金属污染检测技术和饮用水资源监测以及其他生化传感领域的应用。