Cheng K, Tarjan P P, Mertz P M
Dept. of Derm. and BME, University of Miami, Coral Gables, FL 33101.
Biomed Sci Instrum. 1993;29:349-54.
Our previous in vivo experimental results have shown RPES can enhance skin wound healing by using conforming electrodes. Based on an equation of polarization transmembrane voltage [Cole, K. S. 1972], two equations were derived to describe the peak RPES intensity on skin cells in vivo: (1) U = 1.5 a J/sigma, (2) Jm = 1.5 a (J/sigma) (Cm/tau). Where U: polarization transmembrane voltage. a: radius (R) for spherical cells or semi-length (L) for long fibers parallel to the electrical field. J: external imposed pulse current density under the electrode. sigma: average conductivity of skin tissue. Jm: transmembrane displacement current density. Cm: membrane capacitance per unit area and tau: time constant. Calculations indicated that the sensory fibers (SF) would receive the strongest stimulation compared to other cells in skin since generally LSF > or = 100 R. The sensitivity of SF to the stimulation could enhance skin wound healing as well as protect normal skin cells from harmful electroporation. From these theoretical calculations. We proposed a theoretical range of the pulse current density as: U1 sigma/(1.5 L) < or = J < or = U2 sigma/(1.5 L), where U1 and U2 are the excitation threshold voltage (about 0.01 V) and polarization electroporation voltage (about 0.1 V) for a SF respectively, for RPES to enhance skin wound healing.
我们之前的体内实验结果表明，通过使用贴合电极，随机脉冲电刺激（RPES）可以促进皮肤伤口愈合。基于极化跨膜电压方程[科尔，K.S.1972]，推导了两个方程来描述体内皮肤细胞上的RPES峰值强度：（1）U = 1.5aJ/σ，（2）Jm = 1.5a（J/σ）（Cm/τ）。其中U：极化跨膜电压。a：球形细胞的半径（R）或与电场平行的长纤维的半长度（L）。J：电极下的外部施加脉冲电流密度。σ：皮肤组织的平均电导率。Jm：跨膜位移电流密度。Cm：单位面积的膜电容，τ：时间常数。计算表明，与皮肤中的其他细胞相比，感觉纤维（SF）将受到最强的刺激，因为通常LSF≥100R。SF对刺激的敏感性可以促进皮肤伤口愈合，并保护正常皮肤细胞免受有害的电穿孔。从这些理论计算中。我们提出了脉冲电流密度的理论范围为：U1σ/（1.5L）≤J≤U2σ/（1.5L），其中U1和U2分别是SF的激发阈值电压（约0.01V）和极化电穿孔电压（约0.1V），用于RPES促进皮肤伤口愈合。
