title: Disposable surface plasmon resonance aptasensor with membrane-based sample handling design for quantitative interferon-gamma detection.
abstract: ELISA and ELISPOT methods are utilized for interferon-gamma (IFN-γ) release assays (IGRAs) to detect the IFN-γ secreted by T lymphocytes. However, the multi-step protocols of the assays are still performed with laboratory instruments and operated by well-trained people. Here, we report a membrane-based microfluidic device integrated with a surface plasmon resonance (SPR) sensor to realize an easy-to-use and cost effective multi-step quantitative analysis. To conduct the SPR measurements, we utilized a membrane-based SPR sensing device in which a rayon membrane was located 300 μm under the absorbent pad. The basic equation covering this type of transport is based on Darcy's law. Furthermore, the concentration of streptavidin delivered from a sucrose-treated glass pad placed alongside the rayon membrane was controlled in a narrow range (0.81 μM ± 6%). Finally, the unbound molecules were removed by a washing buffer that was pre-packed in the reservoir of the chip. Using a bi-functional, hairpin-shaped aptamer as the sensing probe, we specifically detected the IFN-γ and amplified the signal by binding the streptavidin. A high correlation coefficient (R(2) = 0.995) was obtained, in the range from 0.01 to 100 nM. A detection limit of 10 pM was achieved within 30 min. Thus, the SPR assay protocols for IFN-γ detection could be performed using this simple device without an additional pumping system.
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei, 10617, Taiwan.
authors.forename: Tsung-Liang
authors.initials: TL
authors.lastname: Chuang
authors.forename: Chia-Chen
authors.initials: CC
authors.lastname: Chang
authors.forename: Yu
authors.initials: Y
authors.lastname: Chu-Su
authors.forename: Shih-Chung
authors.initials: SC
authors.lastname: Wei
authors.forename: Xi-hong
authors.initials: XH
authors.lastname: Zhao
authors.forename: Po-Ren
authors.initials: PR
authors.lastname: Hsueh
authors.forename: Chii-Wann
authors.initials: CW
authors.lastname: Lin
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D004867:Equipment Design; D061925:Immobilized Nucleic Acids / Q000737:chemistry; D007371:Interferon-gamma / Q000032:analysis*; D008567:Membranes, Artificial; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D015336:Molecular Probe Techniques / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D052157:Aptamers, Nucleotide; D061925:Immobilized Nucleic Acids; D008567:Membranes, Artificial; D007371:Interferon-gamma