Experimental Study on in vivo Impedance Spectrums of Mice's Back Skin
Li Ying1, Song Bing2, Liu Zhipeng1, Yin Tao1#*
1(Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300192, China) 2(School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff CF144XY, UK)
Abstract：Different from other tissues, it is difficult to study the impedance of stratum corneum regarding skin as a whole subject, due to its huge impedance. The aim of this work is to non-invasively examine the characteristics of the impedance of mice’s back skin including stratum corneumin vivo. Using Agilent 4294A impedance analyzer, impedance spectrums of the back skin of 15 C57BL/6 mice under anesthesia were measured, and surface electrodes and acupuncture needles were used to record data as the whole skin and viable skin respectively. Along with the increase of frequency, the amplitude of impedance of the whole skin declined at the rate of -20 dB/dec within all the frequency span from 40 Hz to 107 Hz; whereas that of the viable skin decreased at -10 dB/dec in the range of 40 Hz to103 Hz, and at -3 dB/dec in the range of 103 Hz to 107 Hz. The phase of the whole skin decreased and then increased in a V-shape curve, and that of viable skin varied as a Π-shape curve. At low frequencies, such as 100 Hz, the whole skin impedance can be regarded as only consisting of the impedance of stratum corneum, and the viable skin part can be omitted. At medium frequencies, such as 105 Hz, the viable skin contributes over 10% to the whole skin impedance. However, at high frequencies, such as 107 Hz, the viable skin contributed over 80% to the whole skin impedance. The impedance of the whole skin and viable skin showed significant difference below 103 Hz (P<0.05) and no significant difference over 104 Hz. The results showed that this novel method that comparing the impedance recorded by surface electrodes and acupuncture needles was effective in the analysis of the impedance of stratum corneum within the whole skin impedance.
李 颖, 宋 冰, 刘志朋, 殷 涛. 小鼠背部皮肤的在体阻抗谱实验研究[J]. 中国生物医学工程学报, 2017, 36(2): 172-179.
Li Ying, Song Bing, Liu Zhipeng, Yin Tao. Experimental Study on in vivo Impedance Spectrums of Mice's Back Skin. Chinese Journal of Biomedical Engineering, 2017, 36(2): 172-179.
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