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| Thanks to the following for materials & support |
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Self-Referencing Technology
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Measuring chemical changes in the cell and the resulting gradients opens a window into cellular function and control. Historically, monitoring such changes has proven virtually impossible through limitations of sensor stability, sensitivity and selectivity - particularly where interference is recorded from other analytes, high background levels of the analyte in flux or parasitic voltages and currents derived from artifactual sources.
 The impact of these problems can be drastically reduced by using a modulation approach, termed self- referencing.
Self-referencing an electrochemical sensor can improve signal detection by orders of magnitude. The principle is simple. A sensor, with a tip diameter in microns, is placed within the diffusive boundary layer of a cell or tissue. The measured voltage or current, depending on the sensor design, represents the analyte concentration at that position. A second measurement is then made, with the same sensor, at a known distance away, and the two compared. The process is repeated approximately every three seconds depending on signal strength and sensor response time.
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• Measuring oxygen consumption using a self-referencing
electrode >> |
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| Smith, P.J.S., Sanger, R.S. and Messerli, M.A. (2006) Principles, Development and Applications of Self-Referencing Electrochemical Microelectrodes to the Determination of Fluxes at Cell Membranes. In: Methods and New Frontiers in Neuroscience. Ed. Adrian C. Michael. CRC Press. In Press. |
| Messerli, M.A., Robinson, K.R. and Smith, P.J.S. (2006) Electrochemical sensor applications to the study of molecular physiology and analyte flux in plants. In: Plant electrophysiology- Theory and Methods. Ed. Alexander G. Volkov. Springer, In Press. |
| Garber, S.S., Messerli, M.A., Hubert, M., Lewis, R., Hammar, K., Indyk, E. and Smith, P.J.S. 2005. Monitoring Cl- movement in single cells exposed to hypotonic solution. Journal of Membrane Biology, 203:101-110. |
| Osbourn, D.M., Sanger, R. H., and Smith, P.J.S. 2005. Determination of single cell oxygen consumption with impedance feedback for control of sample-probe separation. Analytical Chemistry, 77(21):6999-7004. |
| Messerli, M.A., Smith, P.J.S., Lewis, R.C., Robinson, K.R. 2004. Chloride fluxes in lily pollen tubes: a critical reevaluation. Plant Journal, 40:799-812. |
| Molina, A.J.A., Verzi, M.P., Birnbaum, A.D., Yamoah, E.N., Hammar, K., Smith, P.J.S., Malchow, R.P. 2004. Neurotransmitter modulation of extracellular H+ fluxes from isolated retinal horizontal cells of the skate. Journal of Physiology-London 560:639-657. |
| Bogorff, D.J., Messerli, M.A., Malchow, R.P. and Smith, P.J.S. 2003. Development and characterization of a self-referencing glutamate-selective micro biosensor. Biological Bulletin, 205: 207-208. |
| Cooper, R.A. and Jung, S. 2002. Single cell electrochemistry. In: Encyclopedia of Electrochemistry: 9 (Biochemistry), GS Wilson (ed). Wiley & Sons Publishers. |
| Jung, S.-K., Trimarchi, J.R., Sanger, R.H. and Smith, P.J.S. 2001. Development and application of a self-referencing glucose microsensor for the measurement of glucose consumption by pancreatic beta cells. Analytical Chemistry, 73(15):3759-3767. |
| Porterfield, D.M., Laskin, J.D., Jung, S.-K., Malchow, R.P., Billack, B., P.J.S. Smith and Heck, D.E. 2001. Proteins and lipids define the diffusional field of nitric oxide. American Journal of Physiology, 281(4): L904-912. |
| Smith, P.J.S. and Trimarchi, J.R. 2001. Noninvasive measurement of hydrogen and potassium ion flux from single cells and epithelial structures. American Journal of Physiology, 280: C1-C11. |
| Smith, P.J.S., Haydon, P.G., Hengstenberg, A. and Jung, S.-K. 2001. Analysis of cellular boundrary layers and their modulation by plasma membrane transporters: Application of electrochemical microsensors. Electrochimica Acta, 47(1-2): 283-292. |
| Smith, P.J.S., Hengstenberg, A. and Jung, S.-K. 2001. Measuring molecular flux in the diffusionary boundary layer of cells and tissues. Radiation Research, 156(4): 436-437. |
| Twig, G., Jung, S.-K., Messerli, M., Smith, P.J.S. and Shirihai, O. 2001. Real-time detection of reactive oxygen intermediates from single microglial cells. Biological Bulletin, 201(2): 261-262. |
| Jung, S.-K., Hammar, K. and Smith, P.J.S. 2000. Development of self-referencing oxygen microsensor and its application to HIT cells. Biological Bulletin, 199(2): 197-198. |
| Porterfield, D.M., Corkey, R.F., Sanger, R.H., Tornheim, K., Smith, P.J.S. and Corkey, B.E. 2000. Oxygen consumption oscillates in single clonal pancreatic beta -cells (HIT). Diabetes, 49: 1511-1516. |
| Land, S.C., Porterfield, D.M., Sanger, R.H. and Smith, P.J.S. 1999. The self-referencing oxygen-selective microelectrode: Detection of transmembrane oxygen flux from single cells. Journal of Experimental Biology, 202: 211-218. |
| Smith, P.J.S., Hammar, K., Porterfield, D.M., Sanger, R.H. and Trimarchi, J.R. 1999. A self-referencing, non-invasive, ion-selective electrode for single cell detection of trans-plasma membrane calcium flux. Microscopy Research Techniques, 46: 398-417. |
| Malchow, R.P., Land, S.C., Patel, L.S. and Smith, P.J.S. 1997. Consumption of oxygen by isolated skate retinal photoreceptors measured using a self-referencing oxygen-selective microelectrode. Biological Bulletin, 193: 231-232. |
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Click on any of the above for detailed descriptions of projects.
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Self-referencing technology
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Equipment
