报告名称：《Towards the Oxidative Capacity of Atmospheric   Particles through the Development of Real-time Reactive Oxygen Species   Monitors》

时  间：2017年11月9日上午10时

地  点：暨南大学南校区学院楼会议室（1044）

报告内容简介如下：

WHO has estimated that atmospheric pollution is responsible for more than 7 million premature deaths each year. A large contributor to this mortality is due to atmospheric particulate matter (PM), with PM being linked to lung cancer, cardiovascular disease, and lung disease. A proposed mechanism to explain these health outcomes is through oxidative stress, wherein PM generated through combustion processes introduce a group of free radicals known as reactive oxygen species (ROS) to the body. These ROS impede cell function creating oxidative stress, which can lead to inflammation and cell death.

To investigate this hypothesis, instrumentation to accurately measure particulate matter ROS concentrations, or the oxidative load of particles, are essential. The ideal system should be: sensitive to a wide range of species; collect ultrafine PM with high efficiency; and collect and measure rapidly. Quantification of ROS is a difficult problem both chemically and physically. In order for measurement to take place, PM containing ROS must in most cases be collected into a liquid containing a chemical probe. The degree to which this probe reacts with the PM sample is measured in order to ascertain a value for the concentration of ROS, which is termed oxidative load.

Several systems have been developed to address this, using both commercially available and in-house designed instrumentation coupled with a variety of chemical probes for the detection of ROS. Some probes, including POHPAA, ascorbic acid, and DTT, are only sensitive to narrow ranges of ROS species; making them unsuited for quantification of total ROS activity.In addition, an in-house designed probes based on profluorescent nitroxides (PFN) have also been used (Stevanovic et al, 2012).

Beyond the implementation of a chemical probe, there are several properties of ROS and combustion aerosols which make oxidative load measurements difficult. The high reactivity of ROS causes them to react readily with the atmosphere and other surroundings; leading to ROS on ultrafine particles having estimated half-lives of under 15 minutes. Therefore, delays between capture and measurement typical of filter collection methodologies can lead to significant underestimations in ROS concentrations. This indicates that the best approach for ROS measurement is to collect particles directly into liquid for analysis and immediately apply a chemical probe. As the combustion processes emit particles that are predominantly in the ultrafine size range (< 100 nm) and are also very hydrophobic capturing into a liquid further complicates the process. These attributes make direct collection into liquid a difficult process.