Cholera toxin subunit B detection in microfluidic devices

dc.contributor.authorNatinan Bunyakulen_US
dc.contributor.authorKatie A. Edwardsen_US
dc.contributor.authorChamras Promptmasen_US
dc.contributor.authorAntje J. Baeumneren_US
dc.contributor.otherCornell Universityen_US
dc.contributor.otherMahidol Universityen_US
dc.description.abstractFluorescence and electrochemical microfluidic biosensors were developed for the detection of cholera toxin subunit B (CTB) as a model analyte. The microfluidic devices were made from polydimethylsiloxane (PDMS) using soft lithography from silicon templates. The polymer channels were sealed with a glass plate and packaged in a polymethylmethacrylate housing that provided leakproof sealing and a connection to a syringe pump. In the electrochemical format, an interdigitated ultramicroelectrode array (IDUA) was patterned onto the glass slide using photolithography, gold evaporation and lift-off processes. For CTB recognition, CTB-specific antibodies were immobilized onto superparamagnetic beads and ganglioside GM1was incorporated into liposomes. The fluorescence dye sulforhodamine B (SRB) and the electroactive compounds potassium hexacyanoferrate (II)/hexacyanoferrate (III) were used as detection markers that were encapsulated inside the liposomes for the fluorescence and electrochemical detection formats, respectively. Initial optimization experiments were carried out by applying the superparamagnetic beads in microtiter plate assays and SRB liposomes before they were transferred to the microfluidic systems. The limits of detection (LoD) of both assay formats for CTB were found to be 6.6 and 1.0 ng mL-1for the fluorescence and electrochemical formats, respectively. Changing the detection system was very easy, requiring only the synthesis of different marker-encapsulating liposomes, as well as the exchange of the detection unit. It was found that, in addition to a lower LoD, the electrochemical format assay showed advantages over the fluorescence format in terms of flexibility and reliability of signal recording. © 2008 Springer-Verlag.en_US
dc.identifier.citationAnalytical and Bioanalytical Chemistry. Vol.393, No.1 (2009), 177-186en_US
dc.rightsMahidol Universityen_US
dc.subjectBiochemistry, Genetics and Molecular Biologyen_US
dc.titleCholera toxin subunit B detection in microfluidic devicesen_US