On-line Measurement of the Capacity of Airborne Particulate Matter to Generate Reactive Oxygen Species

项目摘要 空气中颗粒物的氧化能力与氧化物的产生有关， 在体外和体内均受到应力。近年来，流行病学研究已经发现， 细胞氧化应激与几种常见疾病如哮喘、慢性阻塞性肺病 （COPD）、阿尔茨海默氏症和其他神经系统疾病。尽管最近的研究发现， 颗粒物暴露高峰是健康威胁的重要因素，目前可用的化学品和 确定周围颗粒氧化能力的体外测定需要大量样品，因此需要很长时间。 采样周期，通常为24至48小时。 提出了一种气溶胶氧化能力的在线监测器的开发， 气载粒子产生活性氧物质能力的时间分辨评估 （ROS）。我们的方法结合了在第一阶段优化的化学模块，用于在线测量 气溶胶的氧化能力，以及我们公司的新颗粒生长技术，将颗粒直接收集到 少量液体。气溶胶收集器采用水冷凝生长技术， 将小至10 nm的颗粒收集到浓缩的水悬浮液中，效率> 90%。的 收集的颗粒的氧化电位将使用通常称为 DTT（二硫苏糖醇）测定。我们的方法有效地收集了可溶性和不溶性成分， 颗粒物质直接进入少量水中，并在现场分析该样品， 时间分辨分析直接收集和快速分析还减少了与长过滤器相关的伪影 收集期和提取期。能够准确表征气溶胶的氧化潜力， 将提供更完整的数据集，以便更好地评估可能的不利影响。 与暴露于环境颗粒物引起的氧化应激反应有关的结果。 在第一阶段，我们通过开发一个实验室原型来展示我们的方法，该原型在 实验室的再现性和灵敏度，并成功地运行无人值守3天，提供3小时 环境颗粒物ROS容量的时间分辨率。在第二阶段，我们将制作一个便携，坚固， 和全自动化系统，用于无人值守的现场操作。具体目标是：（一）制定一项契约， 我们的第一阶段化学模块的更敏感的版本; ii）将该化学模块与改进的 iii）扩展分析能力，以区分 金属和有机物对颗粒氧化能力的贡献; iv）系统性能的证明 在现场条件下。

Project summary The oxidative capacity of airborne particulate matter has been correlated with the generation of oxidative stress both in-vitro and in-vivo. In recent years, epidemiological studies have associated damaged caused by cellular oxidative stress with several common diseases such as asthma, chronic obstructive pulmonary disease (COPD), Alzheimer's and other neurological diseases. Even though recent studies have identified short-term peaks in particulate matter exposures as important factors in health threat, currently available chemical and in- vitro assays to determine the oxidative capacity of ambient particles require large samples, and hence long sampling periods, typically 24 to 48 hours. Proposed is the development of an on-line monitor of the oxidative capacity of aerosols to provide on-line, time-resolved assessment of the capacity of airborne particles to generate reactive oxygen species (ROS). Our approach combines a chemical module optimized in Phase I for on-line measurement of the oxidative capacity of aerosol, and our firm's new particle growth technology to collect particles directly into small volumes of liquid. The aerosol collector uses the water condensational growth technology that allows collection of particles as small as 10 nm into concentrated water suspensions with efficiencies >90%. The oxidative potential of the collected particles will be measured using the chemical assay commonly known as the DTT (dithiothreitol) assay. Our approach efficiently collects both soluble and insoluble constituents of particulate matter directly into a small volume of water, and analyzes this sample in-field to provide immediate, time-resolved analysis. The direct collection and rapid analysis also reduces artifacts associated with long filter collection periods and extraction. The ability to characterize the oxidative potential of aerosols accurately and in a time-resolved manner will provide a more complete data set for better assessing possible adverse outcomes related to oxidative stress responses resulting from exposure to ambient particulate matter. In Phase I, we demonstrated our approach by developing a laboratory prototype that was validated in the laboratory for reproducibility and sensitivity, and that successfully ran unattended for 3 days, providing 3-hour time resolution of the ROS capacity of ambient particulate matter. In Phase II, we will make a portable, robust and fully automated system for unattended field operation. Specific aims are: i) development of a compact and more sensitive version of our Phase I chemical module; ii) integration of this chemical module with an improved version of the commercially available Liquid Spot Sampler; iii) extension of analysis capability to distinguish the contribution of metals and organics to particle oxidative capacity; iv) demonstration of the system performance under field conditions.