Papers Published

1. Lee, D.C. and Grill, W.M., Polarization of a spherical cell in a non-uniform electric field: transient response and comparison with polarization in a uniform field, Conference Proceedings. Second Joint EMBS-BMES Conference 2002. 24th Annual International Conference of the Engineering in Medicine and Biology Society. Annual Fall Meeting of the Biomedical Engineering Society (Cat. No.02CH37392), vol. vol.3 (2002), pp. 1980 - 1 [IEMBS.2002.1053126] .
   (last updated on 2007/04/13)

   Abstract:
   Polarization of cells by extracellular fields is relevant to neural stimulation, cardiac pacing, and cardiac defibrillation. When electrodes are positioned close to cells the electric field is non-uniform, but in many cases has been assumed to be uniform. We solved analytically for the transmembrane voltage (φ_m) generated in a spherical cell by a non-uniform extracellular field, as would arise from a point electrode. φ_m reached its steady state value with a time constant much less than the membrane time constant in both uniform and non-uniform fields. The magnitude of φ_m in the hemisphere of the cell toward the electrode was larger than in the other hemisphere under the non-uniform field, while symmetric polarization occurred under the uniform field. The magnitude of the differences in φ_m generated by the uniform and nonuniform fields decreased as the distance between the cell and electrode increased, and was less than 10% for electrode to cell distances greater than 10 times the cell diameter. The specific polarization generated by a non-uniform field should be considered for small electrode to cell distances

   Keywords:
   bioelectric phenomena;biological effects of fields;cellular biophysics;electric field effects;physiological models;