title: Passive fluidic chip composed of integrated vertical capillary tubes developed for on-site SPR immunoassay analysis targeting real samples.
abstract: We have successfully developed a surface plasmon resonance (SPR) measurement system for the on-site immunoassay of real samples. The system is composed of a portable SPR instrument (290 mm(W) × 160 mm(D) × 120 mm(H)) and a microfluidic immunoassay chip (16 mm(W) × 16 mm(D) × 4 mm(H)) that needs no external pump system. An integrated vertical capillary tube functions as a large volume (150 μL) passive pump and a waste reservoir that has sufficient capacity for several refill operations. An immunoassay was carried out that employed the direct injection of a buffer and a test sample in sequence into a microfluidic chip that included 9 antibody bands and 10 reference reagent bands immobilized in the flow channel. By subtracting a reliable averaged reference sensorgram from the antibody, we effectively reduced the influence of the non-specific binding, and then our chip successfully detected the specific binding of spiked IgG in non-homogeneous milk. IgG is a model antigen that is certain not to be present in non-homogeneous milk, and non-homogeneous milk is a model of real sample that includes many interfering foreign substances that induce non-specific binding. The direct injection of a real sample with no pretreatment enabled us to complete the entire immunoassay in several minutes. This ease of operation and short measuring time are acceptable for on-site agricultural, environmental and medical testing.
authors.affiliation: NTT Microsystem Integration Laboratories, Atsugi 240198, Japan. horiuchi.tsutomu@lab.ntt.co.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Horiuchi
authors.forename: Toru
authors.initials: T
authors.lastname: Miura
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Iwasaki
authors.forename: Michiko
authors.initials: M
authors.lastname: Seyama
authors.forename: Suzuyo
authors.initials: S
authors.lastname: Inoue
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Takahashi
authors.forename: Tsuneyuki
authors.initials: T
authors.lastname: Haga
authors.forename: Emi
authors.initials: E
authors.lastname: Tamechika
mesh_terms: D000818:Animals; D000941:Antigens / Q000032:analysis; D002138:Calibration; D007118:Immunoassay / Q000295:instrumentation*; D007074:Immunoglobulin G / Q000032:analysis; D008024:Ligands; D016014:Linear Models; D044085:Microfluidics / Q000295:instrumentation*; D008892:Milk / Q000737:chemistry*; D012212:Rheology; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D000941:Antigens; D007074:Immunoglobulin G; D008024:Ligands