We report label-free detection of single mitochondria with high sensitivity using nanoelectrodes. Measurements of the conductance of carbon nanotube transistors show discrete changes of conductance as individual mitochondria flow over the nanoelectrodes in a microfluidic channel. Altering the bioenergetic state of the mitochondria by adding metabolites to the flow buffer induces changes in the mitochondrial membrane potential detected by the nanoelectrodes. During the time when mitochondria are transiently passing over the nanoelectrodes, this (nano) technology is sensitive to fluctuations of the mitochondrial membrane potential with a resolution of 10 mV with temporal resolution of order milliseconds. Fluorescence based assays (in ideal, photon shot noise limited setups) are shown to be an order of magnitude less sensitive than this nano-electronic measurement technology. This opens a new window into the dynamics of an organelle critical to cellular function and fate.
Katayoun Zanda, Ted D.A. Phamb, Jinfeng Lia, Weiwei Zhoua, Douglas C. Wallacec, Peter J. Burkea, ,
a Integrated Nanosystems Research Facility, Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA 92697, United States
b Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, United States
c Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
Received 12 July 2016, Revised 23 February 2017, Accepted 21 June 2017, Available online 24 June 2017