Analytical and Bioanalytical Chemistry

, Volume 385, Issue 8, pp 1414–1420

A novel enhancement assay for immunochromatographic test strips using gold nanoparticles

  • Ryo Tanaka
  • Teruko Yuhi
  • Naoki Nagatani
  • Tatsuro Endo
  • Kagan Kerman
  • Yuzuru Takamura
  • Eiichi Tamiya
Original Paper

DOI: 10.1007/s00216-006-0549-4

Cite this article as:
Tanaka, R., Yuhi, T., Nagatani, N. et al. Anal Bioanal Chem (2006) 385: 1414. doi:10.1007/s00216-006-0549-4

Abstract

The immunochromatographic assay is a well-known and convenient diagnostic system. In this report, the development of a novel enhancement assay for the test strips is described. Additionally, this highly sensitive immunochromatographic assay was applied to detect human chorionic gonadotropin hormone (HCG) as the model case. The primary antibody-conjugated gold nanoparticles were used as the enhancer of the standard method. The primary antibodies were immobilized within a defined detection zone (test line) on the diagnostic nitrocellulose membrane. The secondary antibodies were conjugated with colloidal gold nanoparticles. In combination with an effective sample pretreatment, the gold-conjugated antibodies and the primary antibodies formed a sandwich complex with the target protein. Within the test line, the sandwich complex was immobilized, and furthermore, concentrated by the enhancer resulting in a localized surface plasmon resonance (LSPR) phenomenon and a distinct red color on the test line. The intensity of color of the red test line (signal intensity), which correlated directly with the concentration of the target protein in the standard or spiked samples, was assessed visually and by computer image analysis using a three-determination analysis. Under optimum conditions, the limit of detection (LOD) for HCG assay was 1 pg/mL. When using human serum, 10 pg/mL of HCG could be detected. We have also spiked total prostate-specific antigen (TPSA) in female serum. The LOD for TPSA was determined as 0.2 ng/mL. With this method, the quantitative determination of the target protein could be completed in less than 15 min. Our novel immunochromatographic strips using the enhancing method based on LSPR of gold nanoparticles are useful as a rapid and simple screening method for the detection of important analytes for medical applications, environmental monitoring, food control, and biosecurity.

https://static-content.springer.com/image/art%3A10.1007%2Fs00216-006-0549-4/MediaObjects/216_2006_549_Figa_HTML.jpg

Keywords

Gold immunochromatographic assayColloidal gold nanoparticlesHuman chorionic gonadotropin hormoneTotal prostate-specific antigen

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Ryo Tanaka
    • 1
  • Teruko Yuhi
    • 2
  • Naoki Nagatani
    • 2
    • 3
  • Tatsuro Endo
    • 4
  • Kagan Kerman
    • 1
  • Yuzuru Takamura
    • 1
  • Eiichi Tamiya
    • 1
  1. 1.School of Materials ScienceJapan Advanced Institute of Science and Technology (JAIST)NomiJapan
  2. 2.Japan Science and Technology Agency (JST)NomiJapan
  3. 3.Department of Biotechnology and Applied Chemistry, Faculty of EngineeringOkayama University of ScienceOkayamaJapan
  4. 4.Department of Mechano-Micro Engineering, Interdisciplinary Graduate School of Science and EngineeringTokyo Institute of TechnologyMidori-kuJapan