title: On-chip diagnosis of subclinical mastitis in cows by electrochemical measurement of neutrophil activity in milk.
abstract: Subclinical mastitis is a common infectious disease affecting dairy cows. To develop an early diagnostic device for this disease, we focused on measuring an increase in the number of neutrophils in raw milk of mastitic cows. Superoxide anions (O(2)(-)), secreted by neutrophils, can be a good indicator of neutrophil concentration, and therefore, the seriousness of the mastitis. In this study, neutrophils in raw milk samples were separated from fat globules in a flow channel using differences in specific gravity and specific adhesion of neutrophils to P-selectin. Neutrophils trapped in the flow channel were subsequently concentrated in an array of micropillars of a working electrode modified with P-selectin and superoxide dismutase. The O(2)(-) secreted from the trapped neutrophils was electrochemically detected. A difference in the detection current was observed between normal and mastitic milk samples. A clear linear relationship between the electric current and cell density was observed.
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Kimura
authors.forename: Junji
authors.initials: J
authors.lastname: Fukuda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tajima
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D000838:Anions / Q000737:chemistry; D002417:Cattle; D045744:Cell Line, Tumor; D055664:Electrochemical Techniques; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000378:metabolism; D005260:Female; D006801:Humans; D008414:Mastitis, Bovine / Q000175:diagnosis*; D008892:Milk / Q000166:cytology; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism*; D019007:P-Selectin / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000032:analysis
chemical_list: D000838:Anions; D004800:Enzymes, Immobilized; D019007:P-Selectin; D013481:Superoxides; D013482:Superoxide Dismutase