title: Ultrasensitive detection of proteins and sugars at single-cell level.
abstract: Each cell produces its own responses even if it appears identical to other cells. To analyze these individual cell characteristics, we need to measure trace amounts of molecules in a single cell. Nucleic acids in a single cell can be easily amplified by polymerase chain reaction, but single-cell measurement of proteins and sugars will require de novo techniques. In the present study, we outline the techniques we have developed toward this end. For proteins, our ultrasensitive enzyme-linked immunosorbent assay (ELISA) coupled with thionicotinamide-adenine dinucleotide cycling can detect proteins at subattomoles per assay. For sugars, fluorescence correlation spectroscopy coupled with glucose oxidase-catalyzed reaction allows us to measure glucose at tens of nM. Our methods thus offer versatile techniques for single-cell-level analyses, and they are hoped to strongly promote single-cell biology as well as to develop noninvasive tests in clinical medicine.
authors.affiliation: R&D Department, BL Co., Ltd. , Izunokuni, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watabe
authors.affiliation: R&D Headquarters, TAUNS Laboratories, Inc., Izunokuni, Japan; Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Morikawa
authors.affiliation: Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University , Sanuki, Japan.
authors.forename: Mugiho
authors.initials: M
authors.lastname: Kaneda
authors.affiliation: R&D Headquarters, TAUNS Laboratories, Inc. , Izunokuni, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Nakaishi
authors.affiliation: Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University , Sanuki, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Nakatsuma
authors.affiliation: Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University , Sanuki, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Ninomiya
authors.affiliation: Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido , Ishikari-Tobetsu, Japan.
authors.forename: Teruki
authors.initials: T
authors.lastname: Yoshimura
authors.affiliation: Graduate School of Pharmaceutical Sciences, Hokkaido University , Sapporo, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Miura
authors.affiliation: Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University , Sanuki, Japan.
authors.forename: Etsuro
authors.initials: E
authors.lastname: Ito
keywords: HIV-1 p24; adiponectin; fluorescence correlation spectroscopy; insulin; thio-NAD cycling