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A critical analysis of single-frequency LCR databridge impedance measurements of human skin.

Authors
White-EA; Orazem-ME; Bunge-AL
Source
Toxicol In Vitro 2011 Jun; 25(4):774-784
NIOSHTIC No.
20039405
Abstract
Testing whether the barrier of skin samples has sufficient integrity for meaningful measurements of in-vitro chemical permeability is usually required when data are generated for regulatory purposes. Recently, skin integrity has been assessed using LCR databridge measurements, which are reported as resistances determined in either series (SER) or parallel (PAR) modes at a single frequency, typically 100 or 1000Hz. Measurements made at different combinations of mode and frequency are known to differ, although the skin literature reveals confusion over the meaning of these differences and the impact on the interpretation of integrity test results. Here, the theoretical meanings of resistance and capacitance measurements in PAR and SER mode are described and confirmed experimentally. SER-mode resistances are equal to the real part of the complex impedance; whereas, PAR-mode resistances are the inverse of the real part of the admittance. Capacitance measurements reported in SER and PAR modes are similar manipulations of the imaginary parts of the complex impedance and admittance. A large body of data from human cadaver skin is used to show that the PAR-mode resistance and SER-mode capacitance measured at 100Hz are sensitive to skin resistivity, which is the electrical measurement most closely related to skin integrity.
Keywords
Skin; Skin-absorption; Skin-exposure; Humans; Men; Women; In-vitro-study; Author Keywords: Electrical impedance spectroscopy; Skin barrier function; Stratum corneum; Skin integrity; In-vitro; Constant phase element
Contact
Annette L. Bunge, Chemical Engineering Department, Colorado School of Mines, Golden, CO 80401
CODEN
TIVIEQ
Publication Date
20110601
Document Type
Journal Article
Funding Type
Grant
Fiscal Year
2011
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-007493
Issue of Publication
4
ISSN
0887-2333
Source Name
Toxicology in Vitro
State
CO; FL
Performing Organization
Colorado School of Mines
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