{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T12:05:05Z","timestamp":1769601905075,"version":"3.49.0"},"reference-count":39,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2012,5,29]],"date-time":"2012-05-29T00:00:00Z","timestamp":1338249600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>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) x 160 mm(D) x 120 mm(H)) and a microfluidic immunoassay chip (16 mm(W) x 16 mm(D) x 4 mm(H)) that needs no external pump system. An integrated vertical capillary tube functions as a large volume (150 \u03bcL ) 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, environmentaland medical testing.<\/jats:p>","DOI":"10.3390\/s120607095","type":"journal-article","created":{"date-parts":[[2012,5,29]],"date-time":"2012-05-29T11:48:24Z","timestamp":1338292104000},"page":"7095-7108","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Passive Fluidic Chip Composed of Integrated Vertical Capillary Tubes Developed for On-Site SPR Immunoassay Analysis Targeting Real Samples"],"prefix":"10.3390","volume":"12","author":[{"given":"Tsutomu","family":"Horiuchi","sequence":"first","affiliation":[{"name":"NTT Microsystem Integration Laboratories, Atsugi 240198, Japan"}]},{"given":"Toru","family":"Miura","sequence":"additional","affiliation":[{"name":"NTT Microsystem Integration Laboratories, Atsugi 240198, Japan"}]},{"given":"Yuzuru","family":"Iwasaki","sequence":"additional","affiliation":[{"name":"NTT Microsystem Integration Laboratories, Atsugi 240198, Japan"}]},{"given":"Michiko","family":"Seyama","sequence":"additional","affiliation":[{"name":"NTT Microsystem Integration Laboratories, Atsugi 240198, Japan"}]},{"given":"Suzuyo","family":"Inoue","sequence":"additional","affiliation":[{"name":"NTT Microsystem Integration Laboratories, Atsugi 240198, Japan"}]},{"given":"Jun-ichi","family":"Takahashi","sequence":"additional","affiliation":[{"name":"NTT Microsystem Integration Laboratories, Atsugi 240198, Japan"}]},{"given":"Tsuneyuki","family":"Haga","sequence":"additional","affiliation":[{"name":"NTT Microsystem Integration Laboratories, Atsugi 240198, Japan"}]},{"given":"Emi","family":"Tamechika","sequence":"additional","affiliation":[{"name":"NTT Microsystem Integration Laboratories, Atsugi 240198, Japan"}]}],"member":"1968","published-online":{"date-parts":[[2012,5,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1493","DOI":"10.1021\/ac010903q","article-title":"A strip liposome immunoassay for Aflatoxin B1","volume":"74","author":"Ho","year":"2002","journal-title":"Anal. Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1345","DOI":"10.1046\/j.1365-2036.2003.01577.x","article-title":"Review article: Clinic-based testing for Helicobacter pylori infection by enzyme immunoassay of faeces, urine and saliva","volume":"17","author":"Kabir","year":"2003","journal-title":"Aliment. Pharmacol. Ther."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"98","DOI":"10.1021\/ac034694g","article-title":"An analytical device for on-site immunoassay. demonstration of its applicability in semiquantitative detection of Aflatoxin B1 in a batch of samples with Ultrahigh Sensitivity","volume":"76","author":"Pal","year":"2004","journal-title":"Anal. Chem."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1191","DOI":"10.1039\/b800297e","article-title":"Silane-dextran chemistry on lateral flow polymer chips for immunoassays","volume":"8","author":"Aronsson","year":"2008","journal-title":"Lab Chip"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1016\/j.bios.2008.06.045","article-title":"Towards on-site pathogen detection using antibody-based sensors","volume":"24","author":"Skottrup","year":"2008","journal-title":"Biosens. Bioelectron."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"963","DOI":"10.1016\/S0956-5663(98)00008-6","article-title":"Separation-free electrochemical immunosensor for rapid determination of atrazine","volume":"13","author":"Keay","year":"1998","journal-title":"Biosens. Bioelectron."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"4641","DOI":"10.1021\/es001099c","article-title":"On-site immunoanalysis of nitrate and nitroaromatic compounds in Groundwater","volume":"34","author":"Charles","year":"2000","journal-title":"Environ. Sci. Technol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"704","DOI":"10.1021\/es990815b","article-title":"On-site detection of explosives in Groundwater with a fiber optic biosensor","volume":"34","author":"Bakaltcheva","year":"2000","journal-title":"Environ. Sci. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1061","DOI":"10.1021\/ac0157268","article-title":"Demonstration of four immunoassay formats using the array biosensor","volume":"74","author":"Sapsford","year":"2002","journal-title":"Anal. Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"106","DOI":"10.1016\/S0925-4005(00)00718-8","article-title":"Novel spectral fiber optic sensor based on surface plasmon resonance","volume":"74","author":"Homola","year":"2001","journal-title":"Sens. Actuat. B: Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"791","DOI":"10.1016\/j.snb.2004.11.069","article-title":"Compact surface plasmon resonance (SPR) immunosensor using multichannel for simultaneous detection of small molecule compounds","volume":"108","author":"Kawazumi","year":"2005","journal-title":"Sens. Actuat. B: Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1016\/j.snb.2005.09.025","article-title":"Miniaturized portable surface plasmon resonance immunosensor applicable for on-site detection of low-molecular-weight analytes","volume":"115","author":"Kim","year":"2006","journal-title":"Sens. Actuat. B: Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"519","DOI":"10.1016\/j.bios.2006.07.030","article-title":"A miniaturized germanium-doped silicon dioxide-based surface plasmon resonance waveguide sensor for immunoassay detection","volume":"22","author":"Huang","year":"2006","journal-title":"Biosens. Bioelectron."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"5525","DOI":"10.1021\/ac060480y","article-title":"On-chip enzyme immunoassay of a cardiac marker using a microfluidic device combined with a portable surface plasmon resonance system","volume":"78","author":"Kurita","year":"2006","journal-title":"Anal. Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1016\/j.bios.2007.07.001","article-title":"Towards integrated and sensitive surface plasmon resonance biosensors: A review of recent progress","volume":"23","author":"Hoa","year":"2007","journal-title":"Biosens. Bioelectron."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1382","DOI":"10.1016\/j.bios.2006.06.012","article-title":"Self-assembled PEG monolayer based SPR immunosensor for label-free detection of insulin","volume":"22","author":"Gobi","year":"2007","journal-title":"Biosens. Bioelectron."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.ab.2006.10.040","article-title":"Higher-throughput, label-free, real-time molecular interaction analysis","volume":"361","author":"Rich","year":"2007","journal-title":"Anal. Biochem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"701","DOI":"10.1016\/j.bios.2007.08.010","article-title":"Novel miniature SPR immunosensor equipped with all-in-one multi-microchannel sensor chip for detecting low-molecular-weight analytes","volume":"23","author":"Kim","year":"2007","journal-title":"Biosens. Bioelectron."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"4225","DOI":"10.1021\/ac702632y","article-title":"Postcolumn renewal of sensor surfaces for high-performance liquid chromatography-surface plasmon resonance detection","volume":"80","author":"Du","year":"2008","journal-title":"Anal. Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"412","DOI":"10.1038\/nature05064","article-title":"Microfluidic diagnostic technologies for global public health","volume":"442","author":"Yager","year":"2006","journal-title":"Nature"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2488","DOI":"10.1016\/j.bios.2004.10.016","article-title":"Microfluidic immunosensor systems","volume":"20","author":"Bange","year":"2005","journal-title":"Biosens. Bioelectron."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1016\/0924-4247(93)80213-Z","article-title":"A valveless diffuser\/nozzle-based fluid pump","volume":"39","author":"Stemme","year":"1993","journal-title":"Sens. Actuat. A: Phys."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1039\/b309788a","article-title":"Electrically actuated, pressure-driven microfluidic pumps","volume":"3","author":"Munyan","year":"2003","journal-title":"Lab Chip"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1223","DOI":"10.1039\/b706563a","article-title":"Autonomous microfluidics with stimuli-responsive hydrogels","volume":"3","author":"Dong","year":"2007","journal-title":"Soft Matter"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"795","DOI":"10.1109\/JMEMS.2007.901642","article-title":"Wafer-level process for single-use buckling-film microliter-range pumps","volume":"16","author":"Samel","year":"2007","journal-title":"J. Microelectromech. Syst."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1365","DOI":"10.1021\/ac802006d","article-title":"Integration of low-power microfluidic pumps with biosensors within a laboratory-on-a-chip device","volume":"81","author":"Glidle","year":"2009","journal-title":"Anal. Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"103505:1","DOI":"10.1063\/1.3562037","article-title":"Patterned magnetic traps for magnetophoretic assembly and actuation of microrotor pumps","volume":"98","author":"Henighan","year":"2011","journal-title":"Appl. Phys. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1039\/b403930k","article-title":"Power-free poly(dimethylsiloxane) microfluidic devices for gold nanoparticle-based DNA analysis","volume":"4","author":"Hosokawa","year":"2004","journal-title":"Lab Chip"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1475","DOI":"10.1039\/b707637a","article-title":"Flow rate analysis of a surface tension driven passive micropump","volume":"7","author":"Berthier","year":"2007","journal-title":"Lab Chip"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"6139","DOI":"10.1021\/ac0261449","article-title":"Autonomous microfluidic capillary system","volume":"74","author":"Juncker","year":"2002","journal-title":"Anal. Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1039\/b414566f","article-title":"Dynamics of capillary flow of blood into a microfluidic channel","volume":"5","author":"Chakraborty","year":"2005","journal-title":"Lab Chip"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1330","DOI":"10.1021\/ac048675y","article-title":"High-throughput nanoliter sample introduction microfluidic chip-based flow injection analysis system with gravity-driven flows","volume":"77","author":"Du","year":"2005","journal-title":"Anal. Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"3330","DOI":"10.1039\/b906523g","article-title":"Toward one-step point-of-care immunodiagnostics using capillary-driven microfluidics and PDMS substrates","volume":"9","author":"Gervais","year":"2009","journal-title":"Lab Chip"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"3422","DOI":"10.1039\/b912213c","article-title":"Passive microfluidic pumping using coupled capillary\/evaporation effects","volume":"9","author":"Lynn","year":"2009","journal-title":"Lab Chip"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1148","DOI":"10.1039\/b919942j","article-title":"A unified scaling model for flow through a lattice of microfabricated posts","volume":"10","author":"Srivastava","year":"2010","journal-title":"Lab Chip"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1103\/PhysRev.17.273","article-title":"The dynamics of capillary flow","volume":"17","author":"Washburn","year":"1921","journal-title":"Phys. Rev."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1039\/b408964b","article-title":"High-sensitivity miniaturized immunoassays for tumor necrosis factor [small alpha] using microfluidic systems","volume":"4","author":"Dernick","year":"2004","journal-title":"Lab Chip"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1039\/B609813D","article-title":"Capillary pumps for autonomous capillary systems","volume":"7","author":"Zimmermann","year":"2007","journal-title":"Lab Chip"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"500","DOI":"10.1021\/ja973071f","article-title":"Microfluidic networks for chemical patterning of substrates: Design and application to bioassays","volume":"120","author":"Delamarche","year":"1998","journal-title":"J. Am. Chem. Soc."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/12\/6\/7095\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:50:30Z","timestamp":1760219430000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/12\/6\/7095"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2012,5,29]]},"references-count":39,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2012,6]]}},"alternative-id":["s120607095"],"URL":"https:\/\/doi.org\/10.3390\/s120607095","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2012,5,29]]}}}