title: Evaluation of sensitivity of fluorescence-based asbestos detection by correlative microscopy.
abstract: Fluorescence microscopy (FM) has recently been applied to the detection of airborne asbestos fibers that can cause asbestosis, mesothelioma and lung cancer. In our previous studies, we discovered that the E. coli protein DksA specifically binds to the most commonly used type of asbestos, chrysotile. We also demonstrated that fluorescent-labeled DksA enabled far more specific and sensitive detection of airborne asbestos fibers than conventional phase contrast microscopy (PCM). However, the actual diameter of the thinnest asbestos fibers visualized under the FM platform was unclear, as their dimensions were below the resolution of optical microscopy. Here, we used correlative microscopy (scanning electron microscopy [SEM] in combination with FM) to measure the actual diameters of asbestos fibers visualized under the FM platform with fluorescent-labeled DksA as a probe. Our analysis revealed that FM offers sufficient sensitivity to detect chrysotile fibrils as thin as 30-35 nm. We therefore conclude that as an analytical method, FM has the potential to detect all countable asbestos fibers in air samples, thus approaching the sensitivity of SEM. By visualizing thin asbestos fibers at approximately tenfold lower magnifications, FM enables markedly more rapid counting of fibers than SEM. Thus, fluorescence microscopy represents an advanced analytical tool for asbestos detection and monitoring.
authors.affiliation: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8530, Japan.
authors.forename: Takenori
authors.initials: T
authors.lastname: Ishida
authors.forename: Maxym
authors.initials: M
authors.lastname: Alexandrov
authors.forename: Tomoki
authors.initials: T
authors.lastname: Nishimura
authors.forename: Kenji
authors.initials: K
authors.lastname: Minakawa
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Hirota
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Sekiguchi
authors.forename: Norihiko
authors.initials: N
authors.lastname: Kohyama
authors.forename: Akio
authors.initials: A
authors.lastname: Kuroda
mesh_terms: D000388:Air / Q000032:analysis*; D017632:Asbestos, Serpentine / Q000032:analysis*; D008856:Microscopy, Fluorescence / Q000379:methods*
chemical_list: D017632:Asbestos, Serpentine