"Nanosized voltmeter" enables cellular-wide electric field mapping.
Previously, all biological measurements of intracellular electric fields (E fields), using voltage dyes or patch/voltage clamps, were confined to cellular membranes, which account for <0.1% of the total cellular volume. These membrane-dependent techniques also frequently require lengthy calibration steps for each cell or cell type measured. A new 30-nm "photonic voltmeter", 1000-fold smaller than existing voltmeters, enables, to our knowledge, the first complete three-dimensional E field profiling throughout the entire volume of living cells. These nanodevices are calibrated externally and then applied for E field determinations inside any live cell or cellular compartment, with no further calibration steps. The results indicate that the E fields from the mitochondrial membranes penetrate much deeper into the cytosol than previously estimated, indicating that, electrically, the cytoplasm cannot be described as a simple homogeneous solution, as often approximated, but should rather be thought of as a complex, heterogeneous hydrogel, with distinct microdomains.
Tyner
Katherine M
KM
Toxicology Program and Chemistry Department, University of Michigan, Ann Arbor, Michigan 48105, USA.
Kopelman
Raoul
R
Philbert
Martin A
MA
D000818:Animals; D001253:Astrocytes / Q000502:physiology; D002478:Cells, Cultured; D003600:Cytosol / Q000502:physiology; D004574:Electromagnetic Fields; D005456:Fluorescent Dyes / Q000737:chemistry*; D066298:In Vitro Techniques; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000502:physiology; D053758:Nanoparticles; D011726:Pyridinium Compounds / Q000737:chemistry*; D051381:Rats; D012821:Silanes / Q000737:chemistry*
D005456:Fluorescent Dyes; D011726:Pyridinium Compounds; D012821:Silanes; C050019:1-(3-sulfonatopropyl)-4-(beta)(2-(di-n-butylamino)-6-naphthylvinyl)pyridinium betaine