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

项目总结 空气中颗粒物的氧化能力与氧化物质的生成有关。 在体外和体内都应激。近年来，流行病学研究表明，由 细胞氧化应激与哮喘、慢性阻塞性肺疾病等几种常见病 慢性阻塞性肺病(COPD)、阿尔茨海默氏症和其他神经系统疾病。尽管最近的研究已经确定了短期的 颗粒物暴露的峰值是健康威胁的重要因素，目前可获得的化学品和在- 测定周围颗粒物氧化能力的体外分析需要大量样品，因此需要很长时间。 采样周期，通常为24至48小时。 建议开发一种气溶胶氧化能力在线监测仪，以提供在线， 空气中颗粒物产生活性氧物种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，可以直接将颗粒收集到 少量液体。气溶胶收集器使用水冷凝生长技术，允许 将小至10纳米的颗粒收集到效率为90%的浓缩水悬浮液中。这个 收集到的颗粒物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和不可溶的成分 颗粒物直接进入小体积的水中，并现场分析此样本，以提供即时、 时间分辨分析。直接收集和快速分析还减少了与长滤镜相关的伪影 采集期和提取。准确和准确地表征气溶胶氧化潜势的能力 将提供更完整的数据集，以便更好地评估可能的不利因素 与暴露在周围颗粒物中引起的氧化应激反应有关的结果。 在第一阶段，我们通过开发实验室原型来演示我们的方法，该原型在 实验室的重复性和灵敏度，并成功地运行了3天的无人值守，提供3小时 环境颗粒物的ROS容量的时间分辨率。在第二阶段，我们将使一个可移植的、健壮的 和全自动化系统，用于无人值守的现场操作。具体目标是：一)制定一项契约和 我们第一阶段化学模块的更敏感版本；ii)将该化学模块与改进的 商用液体斑点采样器的版本；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)系统性能演示 在田间条件下。

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.