Direct analysis of airborne mite allergen (Der f1) in the residential atmosphere by chemifluorescent immunoassay using bioaerosol sampler.

Abstract Dermatophagoides farinae allergen ( Der f 1) is one of the most important indoor allergens associated with allergic diseases in humans. Mite allergen Der f 1 is usually associated with particles of high molecular weight; thus, Der f 1 is generally present in settled dust. However, a small quantity of Der f 1 can be aerosolized and become an airborne component. Until now, a reliable method of detecting airborne Der f 1 has not been developed. The aim of this study was to develop a fiber-optic chemifluorescent immunoassay for the detection of airborne Der f 1. In this method, the Der f 1 concentration measured on the basis of the intensity of fluorescence amplified by an enzymatic reaction between the labeled enzyme by a detection antibody and a fluorescent substrate. The measured Der f 1 concentration was in the range from 0.49 to 250 ng/ml and a similar range was found by enzyme-linked immunosorbent assay (ELISA). This method was proved to be highly sensitive to Der f 1 compared with other airborne allergens. For the implementation of airborne allergen measurement in a residential environment, a bioaerosol sampler was constructed. The airborne allergen generated by a nebulizer was conveyed to a newly sampler we developed for collecting airborne Der f 1. The sampler was composed of polymethyl methacrylate (PMMA) cells for gas/liquid phases and some porous membranes which were sandwiched in between the two phases. Der f 1 in air was collected by the sampler and measured using the fiber-optic immunoassay system. The concentration of Der f 1 in aerosolized standards was in the range from 0.125 to 2.0 mg/m 3 and the collection rate of the device was approximately 0.2%.