Disposable surface plasmon resonance aptasensor with membrane-based sample handling design for quantitative interferon-gamma detection

Lab Chip. 2014 Aug 21;14(16):2968-77. doi: 10.1039/c4lc00249k.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aptamers, Nucleotide / chemistry
  • Equipment Design
  • Immobilized Nucleic Acids / chemistry
  • Interferon-gamma / analysis*
  • Membranes, Artificial
  • Microfluidic Analytical Techniques / instrumentation*
  • Molecular Probe Techniques / instrumentation*
  • Surface Plasmon Resonance / instrumentation*

Substances

  • Aptamers, Nucleotide
  • Immobilized Nucleic Acids
  • Membranes, Artificial
  • Interferon-gamma