The proposed project will develop and demonstrate a miniaturized, portable aerosol sampler that will collect a series of time- and location-resolved personal exposure samples for conducting research into the relationships among environmental exposure, genetics and health. It will also develop a bench-top assay unit that will perform colorimetric assays for endotoxin on the collected samples. The sampler will employ an array of novel micro-channel collectors, and, when combined with a position-monitor (GPS) and activity monitor (accelerometer), will collect a time-series of exposure samples that will be time- and location- stamped to allow researchers to fully characterize the exposure history of subjects as they travel through their environment. The sampling unit will be extremely small, light-weight and battery operated to allow it to be carried in a back-pack even by a 10-year old child. This device will significantly improve the ability to localize exposure events in space and time and will provide a critical tool for use in resolving uncertainties about the relationships between exposure and human health impacts. Each sampling unit will contain a carousel holding an array of micro-channel collectors which will collect samples at 30 minute (or shorter) intervals. The carousel will hold up to 48 collectors allowing samples to be collected over a 24 hour period. Once all the samples have been collected, the carousel will be transferred to the bench-top assay unit which will perform assays on all of the collected samples, greatly reducing the workload associated with the analysis of the numerous samples collected during a typical epidemiological study. This aerosol sampling and detection apparatus will be integrated with automation technology developed by the Pacific Northwest National Laboratory (PNNL) to produce a self-contained portable personal exposure sampling unit and a bench-top assay unit. Enertechnix will be responsible for the aerosol sampling and microfluidic components and for system integration. PNNL will adapt its automation, power management, and position- and motion- sensing technologies for use in the PEM. The University of Washington (UW) will assist in the implementation of an endotoxin assay employing a miniature colorimetric readout unit developed by FAR Sciences. Prototypes will be developed and, in collaboration with the UW, will be field tested in a variety of environments to demonstrate the performance of the sampler and bench-top assay unit. This system will be the first to provide a highly efficient aerosol to microfluidics interface and the first to provide automated, time- and space-resolved sampling in a portable package.
There is a growing awareness that exposure to environmental contaminants such as fine particulate matter and diesel particulates can trigger or exacerbate diseases such as asthma and cardiovascular disease, but there is still much uncertainty about the importance of specific factors and the relationship between disease and exposure. Asthma affects between 14 and 15 million people in the United States, about 4.8 million of whom are children;its incidence worldwide has doubled in the last 15 years;and it is responsible for 100 million person-days of restricted activity and 5000 deaths per year, amounting to $8.1 billion in direct health related costs. Endotoxin, a ubiquitous component of gram-negative bacteria, is an important bioactive environmental factor that can induce asthma symptoms: bronchoconstriction, airways inflammation and airways hyper-responsiveness. Endotoxin levels, which are known to be highly variable in space and time, have been correlated with asthma symptoms and disease severity. The proposed project will develop an improved personal exposure monitor that can be used to obtain space- and time-resolved measurements of endotoxin contained in airborne particles in a portable device that can be used in studies to develop a better understanding of the relationships between exposure and human health impacts.