Plasmon-enhanced colorimetric ELISA with single molecule sensitivity

Si Chen, Mikael Svedendahl, Richard P.Van Duyne, Mikael Käll*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

169 Scopus citations


Robust but ultrasensitive biosensors with a capability of detecting low abundance biomarkers could revolutionize clinical diagnostics and enable early detection of cancer, neurological diseases, and infections. We utilized a combination of localized surface plasmon resonance (LSPR) refractive index sensing and the well-known enzyme-linked immunosorbent assay to develop a simple colorimetric biosensing methodology with single molecule sensitivity. The technique is based on spectral imaging of a large number of isolated gold nanoparticles. Each particle binds a variable number of horseradish peroxidase (HRP) enzyme molecules that catalyze a localized precipitation reaction at the particle surface. The enzymatic reaction dramatically amplifies the shift of the LSPR scattering maximum, λmax, and makes it possible to detect the presence of only one or a few HRP molecules per particle.

Original languageEnglish (US)
Pages (from-to)1826-1830
Number of pages5
JournalNano letters
Issue number4
StatePublished - Apr 13 2011


  • Surface plasmon
  • biosensor
  • single molecules
  • single particles
  • spectra imaging

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Bioengineering
  • General Chemistry
  • General Materials Science


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