Transmission of light through model human epidermal samples is investigated at four different wavelengths and at varying ambient humidity. Light from light emitting diodes (LEDs) is used for transmission measurements ...Transmission of light through model human epidermal samples is investigated at four different wavelengths and at varying ambient humidity. Light from light emitting diodes (LEDs) is used for transmission measurements through the samples at a UVA wavelength of 365 nm, and visible wavelengths of 460 nm, 500 nm, and 595 nm. Ambient air-humidity is varied between 20% and 100%. Results show that for high ambient humidity, near 100%, transmission of light through the epidermis is higher than at low ambient humidity, 60% or lower. These results are explained with a simple model of epidermis as a turbid medium and the effect of adsorbed water in reducing light-scattering by refractive-index-matching. Biological implications of increased light-transmission through epidermis at high ambient humidity are discussed.展开更多
Cosmetic safety evaluation employs a series of toxicological tests, on both qualitative and quantitative levels, to assess the potential risks for the daily use of selected cosmetic ingredients and final products. Tra...Cosmetic safety evaluation employs a series of toxicological tests, on both qualitative and quantitative levels, to assess the potential risks for the daily use of selected cosmetic ingredients and final products. Traditionally, safety evaluation of cosmetics uses animal tests. With the development of in vitro science and the 3R （Reduction, Replacement and Refinement） principle, three-dimensional reconstructed human epidermis （3D-RHE） models have been developed and widely applied in cosmetic safety evaluation. Reconstructed human skin models possess anatomy and metabolism biology similar to real human tissue. This paper reviews the current application of 3D-RHE models in the safety evaluation of skin irritation, eye irritation, phototoxicity and genotoxicity potential of cosmetic ingredients/formulas. The advantages and disadvantages of using skin models are also discussed, and comments and suggestions are given for its future development.展开更多
文摘Transmission of light through model human epidermal samples is investigated at four different wavelengths and at varying ambient humidity. Light from light emitting diodes (LEDs) is used for transmission measurements through the samples at a UVA wavelength of 365 nm, and visible wavelengths of 460 nm, 500 nm, and 595 nm. Ambient air-humidity is varied between 20% and 100%. Results show that for high ambient humidity, near 100%, transmission of light through the epidermis is higher than at low ambient humidity, 60% or lower. These results are explained with a simple model of epidermis as a turbid medium and the effect of adsorbed water in reducing light-scattering by refractive-index-matching. Biological implications of increased light-transmission through epidermis at high ambient humidity are discussed.
文摘Cosmetic safety evaluation employs a series of toxicological tests, on both qualitative and quantitative levels, to assess the potential risks for the daily use of selected cosmetic ingredients and final products. Traditionally, safety evaluation of cosmetics uses animal tests. With the development of in vitro science and the 3R （Reduction, Replacement and Refinement） principle, three-dimensional reconstructed human epidermis （3D-RHE） models have been developed and widely applied in cosmetic safety evaluation. Reconstructed human skin models possess anatomy and metabolism biology similar to real human tissue. This paper reviews the current application of 3D-RHE models in the safety evaluation of skin irritation, eye irritation, phototoxicity and genotoxicity potential of cosmetic ingredients/formulas. The advantages and disadvantages of using skin models are also discussed, and comments and suggestions are given for its future development.
