title: Novel endotoxin assay by laser light-scattering particle-counting method.
abstract: Exposure of Limulus amoebocyte lysate to endotoxin under stirring produced light-reflective particles that appeared to be coagulin polymers. A laser light-scattering particle counter, the PA-200, detected these particles sensitively. The PA-200 detected endotoxin at a concentration as low as 0.00015 EU/ml in 71 min, whereas the minimum endotoxin concentration measured by a turbidimeter, ET-2000, was 0.0005 EU/ml in 138 min. Moreover, PA-200 was much less affected by the presence of colored substances and refractive materials than was ET-2000. We propose that the high sensitivity, speed, and high interference tolerance of the laser light-scattering particle-counting method make it more useful than the widely used turbidimetric method for quantitative endotoxin assay.
authors.affiliation: Electronics and Optics Research Laboratories, Kowa Company Ltd., 3-3-1 Chofugaoka, Chofu, Tokyo, Japan. k-mitumt@kowa.co.jp
authors.forename: Kotaro
authors.initials: K
authors.lastname: Mitsumoto
authors.forename: Katsumi
authors.initials: K
authors.lastname: Yabusaki
authors.forename: Koji
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Shirasawa
authors.forename: Toru
authors.initials: T
authors.lastname: Obata
mesh_terms: D000818:Animals; D004731:Endotoxins / Q000032:analysis*; D005217:Fat Emulsions, Intravenous / Q000737:chemistry; D006454:Hemoglobins / Q000737:chemistry; D007834:Lasers; D008027:Light; D008033:Limulus Test / Q000379:methods*; D016015:Logistic Models; D010783:Photometry / Q000379:methods*; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D004731:Endotoxins; D005217:Fat Emulsions, Intravenous; D006454:Hemoglobins