• Open Access

Porphyrins for Probing Electrical Potential Across Lipid Bilayer Membranes by Second Harmonic Generation


  • This work was supported by the Engineering and Physical Sciences Research Council (EPSRC). We thank Edward J. Botcherby and Christopher W. Smith for help with microscopy, and Ismael López-Duarte for preparing JR1.


original image

Feeling the field! The intensity of second harmonic generation (SHG) from a porphyrin in a lipid bilayer is exceptionally sensitive to electric field, thus indicating that these dyes may be useful probes for electrical signals in excitable cells such as neurons. The porphyrin-based membrane probe (see picture, not to scale) gives a fast electro-optic response which is about 5–10 times greater than those of conventional styryl dyes.