Mechanisms of membrane potential sensing with second-harmonic generation microscopy

J Biomed Opt. 2003 Jul;8(3):428-31. doi: 10.1117/1.1581871.


We characterize the transmembrane voltage response of a novel second-harmonic generation (SHG) marker using a screening protocol with giant unilamellar vesicles. Two mechanisms are found to contribute to the voltage response: (1) an electro-optic-induced alteration of the molecular hyperpolarizability and (2) an electric-field-induced alteration of the degree of molecular alignment. We quantify the relative weights and of these contributions and provide an upper limit to their response time, which is found to be submillisecond. The identification of two voltage response mechanisms leads to new strategies for the molecular design of membrane potential markers.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Membrane / physiology
  • Cell Membrane / radiation effects
  • Electric Stimulation
  • Feasibility Studies
  • Fluorescent Dyes / chemistry*
  • Fluorescent Dyes / radiation effects*
  • Lipid Bilayers / chemistry*
  • Lipid Bilayers / radiation effects
  • Liposomes / chemistry*
  • Liposomes / radiation effects
  • Membrane Potentials*
  • Microscopy, Fluorescence, Multiphoton / methods*
  • Phosphatidylcholines / chemistry*


  • Fluorescent Dyes
  • Lipid Bilayers
  • Liposomes
  • Phosphatidylcholines
  • 1,2-oleoylphosphatidylcholine