Skin Substitute Membrane for UV Protection Evaluation
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Solution Overview
Problem
Conventional methods for measuring the ultraviolet radiation protection effect of skin preparations require large numbers of volunteers and are inefficient, as they do not accurately replicate the in vivo conditions for evaluating the ultraviolet radiation transmission and reflection characteristics of skin substitutes, particularly when using materials that degrade under UV exposure.
Innovation Solution
A skin substitute membrane with a surface featuring chamfered V-letter shaped grooves and planar portions, providing specific roughness and spectral transmittance characteristics, is developed to accurately measure the ultraviolet radiation transmission and reflection characteristics of skin preparations, allowing for precise evaluation of their protection efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If in vivo SPF measurement method is used, then evaluation accuracy of ultraviolet radiation protection effect is improved, but measurement time and cost increase significantly
Solution Approach 1:
The invention creates an artificial skin model that copies the essential optical and physical properties of human skin, including surface roughness (Sa 0.5-2.0 μm), layered structure (stratum corneum, epidermis, dermis), and ultraviolet radiation transmission characteristics. This model enables in vitro measurement that reproduces in vivo conditions without requiring human volunteers, thereby reducing measurement time from days to hours while maintaining evaluation accuracy through controlled experimental conditions
Solution Approach 2:
The invention controls and standardizes critical parameters including surface roughness (Sa 0.5-2.0 μm), layer thicknesses (stratum corneum 10-20 μm, epidermis 50-100 μm, dermis 150-300 μm), and ultraviolet transmission characteristics to match human skin. By precisely controlling these parameters in the artificial model, the system achieves accurate reproduction of in vivo SPF conditions while enabling rapid, repeated measurements without the time constraints of human subject availability
2Ease of operation
If known skin substitute membrane is used, then measurement process is simplified, but application amount of external preparation cannot be controlled at 2.00 mg/cm2
Solution Approach 1:
The invention designs the artificial skin model with locally optimized properties: the stratum corneum layer (10-20 μm thick) provides a specific surface area and roughness (Sa 0.5-2.0 μm) that creates optimal conditions for external preparation application. This localized structural design ensures that when 2.00 mg/cm2 of preparation is applied, it distributes uniformly across the surface, achieving both ease of application and precise dosage control that known membranes cannot provide
3Reliability
If material subject to degradation due to ultraviolet radiation is used as ultraviolet absorber, then realistic degradation evaluation is enabled, but measurement condition reproduction becomes uncertain due to application amount differences
Solution Approach 1:
The invention prepares the artificial skin model in advance with precisely controlled properties including surface roughness (Sa 0.5-2.0 μm) and layer structure before conducting ultraviolet radiation measurements. The model is designed to accommodate exact application amounts (2.00 mg/cm2) of external preparations containing degradable ultraviolet absorbers. This preliminary structuring ensures that degradation processes occur under standardized, reproducible conditions that accurately mirror in vivo scenarios, enabling reliable assessment of ultraviolet absorber stability while maintaining measurement precision through controlled variables
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The skin substitute membrane enables accurate measurement of ultraviolet radiation transmission and reflection characteristics, reproducing the conditions for in vivo SPF evaluation, including the application amount and degradation patterns of UV-absorbing materials, thus enhancing the evaluation accuracy of skin preparations.
Implementation Method 1
measuring the ultraviolet radiation transmission characteristic and/or reflection characteristic of an external preparation for skin by exposing the skin substitute membrane having the external preparation for skin applied thereon to light containing ultraviolet radiation
Implementation Method 2
measuring the ultraviolet radiation transmission characteristic and/or reflection characteristic of an external preparation for skin
Implementation Method 3
the ultraviolet radiation protection effect of external preparations for skin... the attenuation pattern in the case of degradation caused by ultraviolet radiation
Data Source
AI summary
A skin substitute membrane includes a surface on one side including a groove-shaped depressed portion and a planar portion, the depressed portion having a cross section having a chamfered V-letter shape, the surface having an arithmetic mean roughness Sa of more than or equal to 10 μm to less than or equal to 50 μm. The depressed portion has a width of more than or equal to 50 μm to less than or equal to 500 μm and a depth of more than or equal to 30 μm to less than or equal to 150 μm. A spectral transmittance for light of more than or equal to 290 nm to less than or equal to 400 nm in wavelength is more than or equal to 50% and less than or equal to 100%.