The Inside Scoop

Probing cells with nanometer-scale electrodes

By | September 1, 2012

image: The Inside Scoop

Cell biologists use microelectrodes to study the real-time biochemistry of cell-to-cell signaling, factor secretion, and other extracellular events. But when it comes to the kinetics of intracellular biochemistry, much smaller electrodes are needed. So Michael Mirkin of the City University of New York, Queens College and colleagues at Université Pierre et Marie Curie have reduced them to nanoscale sizes.

Specifically, they have made nanoelectrodes that are coated with platinum black—a high-surface-area version of platinum used on larger-size electrodes for detecting reactive oxygen and nitrogen species.

Downsizing microelectrodes might sound straightforward, but it is far from simple, says Adrian Michael of the University of Pittsburgh, who was not involved in the study. “What the paper shows is that to do it well you have to do it very carefully and incorporate things like the atomic force microscope so you can watch what you’re doing,” he says.

Mirkin used the microscope to monitor the platinum coating process. “We need to produce an electrode with good geometry”—a smooth shape—“otherwise it will destroy the cell when we punch a hole in the membrane,” he explains.

Electrodes that passed inspection were used to analyze reactive oxygen and nitrogen species inside macrophages, which use these chemicals to kill bacteria and other microbes. The team resolved a long-standing debate about whether these potent chemicals ever leak from their storage vacuoles into the cell itself, and if so, how the cell survives. Apparently leakage does occur, but is cleared up in scant seconds, thus minimizing toxicity.

Besides macrophage biology, says Michael, the electrodes could be used to study any number of situations involving oxidative stress, which is “a matter of great significance in a number of disease states.” (PNAS, 109:11534-39, 2012.) .

Microelectrodes ~100 µm, ~10 µm Real-time extracellular electrochemistry, or static intracellular electrochemistry if cells are lysed No real-time intracellular analysis
Nanoelectrodes ~0.5 µm, ~10–100 nm Real-time intracellular electrochemistry Characterization of the electrode tip is difficult. Electrodes must be checked before each use because performance may deteriorate with time.




Add a Comment

Avatar of: You



Sign In with your LabX Media Group Passport to leave a comment

Not a member? Register Now!

LabX Media Group Passport Logo

Popular Now

  1. Sex Differences in the Brain
    Features Sex Differences in the Brain

    How male and female brains diverge is a hotly debated topic, but the study of model organisms points to differences that cannot be ignored.

  2. DNA Repair Pioneers Win Nobel
    Daily News DNA Repair Pioneers Win Nobel

    Tomas Lindahl, Paul Modrich, and Aziz Sancar have won this year’s Nobel Prize in Chemistry for their work elucidating mechanisms of DNA repair.

  3. Antioxidants Facilitate Melanoma Metastasis
    Daily News Antioxidants Facilitate Melanoma Metastasis

    Two compounds boost the ability of melanoma cells to invade other tissues in mice, providing additional evidence that antioxidants can be beneficial to malignant cells as well as healthy ones.

  4. LabQuiz: Name That Neuron!
Life Technologies