Noninvasive and real-time in vivo characterization of Inflammation skin. A feasibility of animal study

Abstract

Background: Inflammatory skin diseases were the most common problem in dermatology. This study aimed to develop a circuit by using a simple method for noninvasive, objective, and real-time skin inflammation screening.

Materials and methods: Sprague-Dawley rats were used in this study. The rats were chemically induced to suffer from skin inflammation at the back of their left-hand side while the right-hand side of their back remained untreated serving as a control. Impedance (Z) spectrum of the rat's skin was recorded.

Results: Two characteristic frequencies (4.5 and 48.3 kHz) were found. At the two frequencies, the impedance of inflammatory skin tissue (Z_IST ) was found to be significantly (P < .05) smaller than that of normal healthy skin tissue (Z_NHST ). Moreover, the ratio of the impedance measured at 4.5 kHz (Z_{f = 4} ._{5 kHz} ) to the impedance measured at 48.3 kHz (Z_{f = 48.3 kHz} ), that is, Z_{f = 4.5 kHz} /Z_{f = 48.3 kHz} , was capable of skin inflammation screening. It was observed that the inflammatory skin tissue (IST) had the smaller value of Z_{f = 4} ._{5 kHz} /Z_{f = 48.3 kHz} (value < 8.5) and normal healthy skin tissue (NHST) had the higher value of Z_{f = 4} ._{5 kHz} /Z_{f = 48.3 kHz} (value ≈ 10) which almost remained constant.

Conclusion: A circuit was developed which was used for measuring the skin impedance accurately at the two characteristic frequencies for skin inflammation screening.

Keywords: bioimpedance; circuit; noninvasive; screening; skin inflammation.