Pushing the detection limits: the evanescent field in surface plasmon resonance and analyte-induced folding observation of long human telomeric repeats

Biosens Bioelectron. 2012 Jan 15;31(1):571-4. doi: 10.1016/j.bios.2011.11.003. Epub 2011 Nov 10.


Conventional analysis of molecular interactions by surface plasmon resonance is achieved by the observation of optical density changes due to analyte binding to the ligand on the surface. Low molecular weight interaction partners are normally not detected. However, if a macromolecule such as DNA can extend beyond the evanescent field and analyte interaction results in a large-scale contraction, then the refractive index changes due to the increasing amount of macromolecules close to the surface. In our proof-of-principle experiment we could observe the direct folding of long, human telomeric repeats induced by the small analyte potassium using surface plasmon resonance spectroscopy. This work demonstrates the feasibility of new evanescent field-based biosensors that can specifically observe small molecule interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biosensing Techniques / instrumentation*
  • Equipment Design
  • Equipment Failure Analysis
  • Humans
  • Molecular Probe Techniques / instrumentation*
  • Refractometry / instrumentation*
  • Repetitive Sequences, Nucleic Acid / genetics*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Surface Plasmon Resonance / instrumentation*
  • Telomere / genetics*