Presentation is loading. Please wait.

Presentation is loading. Please wait.

Figure 1: The Epsilon Permittivity Imaging System.

Similar presentations


Presentation on theme: "Figure 1: The Epsilon Permittivity Imaging System."— Presentation transcript:

1 Figure 1: The Epsilon Permittivity Imaging System.
Capacitive Imaging For Skin Characterization and Solvent Penetration   Xu Zhang1, Christos Bontozoglou1,2 , and Perry Xiao1,2   1. School of Engineering, London South Bank University, 103 Borough Road, London SE1 0AA, UK 2. Biox Systems Ltd, Technopark Building, 90 London Road, London SE1 6LN, England Introduction Capacitive contact imaging has shown potential in measuring skin properties including hydration, micro relief analysis, as well as solvent penetration measurements [1,2]. Through calibration we can also measure the absolute permittivity of the skin, and from absolute permittivity we then work out the absolute water content (or solvent content) in skin [3]. In this paper, we present our latest study of capacitive contact imaging for skin characterization, i.e. skin hydration and skin damages etc. The results show that the time-dependent occlusion curves of the capacitive contact imaging can reflect the types of damages. We will also show latest results on skin solvent penetrations, to show how solvents penetrate skin, and how to calculate the absolute solvent content in skin. Apparatus The Epsilon Permittivity Imaging System is based on Fujistu fingerprint sensor (Fujistu Ltd), which has 256x300 pixels with 50µm spatial resolution. Each pixel is equivalent of a capacitive sensor, which measures the dielectric constant or permittivity of the sample, it has a 8-bit grey-scale capacitance resolution per pixel ( ). See Figure 1. A) Epsilon and the in-vivo stand B) Epsilon and the in-vitro stand C) Capacitive fingerprint sensor measurement principle [8] Figure 1: The Epsilon Permittivity Imaging System. Epsilon Calibration The Epsilon differs from other such systems in its calibrated, linear response to near-surface dielectric permittivity, see Figure 2. The linear response is important because hydration is linearly related to permittivity. The calibration ensures consistency from instrument to instrument and from time to time. With calibrated Epsilon imaging systems we can measure the absolute dielectric permittivity of the material. . Figure 2. The Epsilon Calibration curve and linear response to dielectric permittivity. Results and Discussions In this study, three types of skin damages were characterized using capacitive contact imaging, i.e. intensive washes, sodium lauryl sulphate (SLS) irritation and tape stripping. Control skin sites (S1) and test skin sites (S2) were chosen on the volar forearm of a healthy volunteer (aged 25–35). The measurements were taken both before and periodically after the damages. The capacitive contact imaging measurements were performed by using capacitive imaging sensor to occlude the skin test sites for a period of one minute, during which skin capacitance images were recorded continuously. The average Epsilon values of the images were then calculated at different times during occlusion. As Epsilon values are proportional to skin hydration, the plots of Epsilon values against time can be interpreted as skin hydration against time. A) B) C) Figure 3. Epsilon values of intensive washes measurements(A), and corresponding S1 occlusion curves (B), as well as S2 occlusion curves (C). A) B) C) Figure 4. Epsilon values of SLS irritation measurements (A), and corresponding S1 occlusion curves (B), as well as S2 occlusion curves (C). A) B) C) Figure 5. Epsilon values of Tape Stripping measurements(A), and corresponding S1 occlusion curves (B), as well as S2 occlusion curves (C). The results show that after intensive washes and SLS irritation, skin has shown a significant drying effect. The tape stripping measurements show the test skin site (S2) continuously increasing during tape stripping. It is also interesting to point out that it seems that the shapes of the capacitive contacting imaging occlusion curves can be related to skin conditions, and different types of skin damages have different shapes of occlusion curves. Figure 6 shows the corresponding capacitive contact images during tape stripping (top) and SLS (Sodium Lauryl Sulfate, 2% v/v) irritation (bottom). By assuming measured Epsilon value (ε ) is linearly dependent on that of dry skin (εdryskin) and water (εwater), we can work out the water content using following equation [6]: H=(ε - εdryskin)/(εwater - εdryskin ) (1) Using Eq.(1) we worked out that during tape stripping measurements skin water content has increased from ~10% to ~60% (v/v) after 12 tape strips. While in SLS irritation measurements, skin water content has decreased from initial ~20% down to ~11% (v/v). Before After Tape Stripping(2strips) strips strips strips strips strips Before After (SLS) min min min min min Figure 6. Capacitive contact images of volar forearm test sites during tape stripping (top), SLS (Sodium Lauryl Sulfate) irritation (bottom). Figure 7 shows solvent penetration through a vitro pig skin sample (nearly 1mm thick). Four solvents (pure alcohol, DMSO, ethylene glycol, and glycerol) were studied and Epsilon video mode was used to record the penetration results during a period of 60mins. A) Alcohol: after 0 min min min min B) Figure 7. Alcohol skin penetration images at 0, 20, 40, 60 min (A), and time dependent penetration curves of four different solvents (B). Figure 7 (A) shows alcohol skin penetration images at 0, 20, 40, 60min. As alcohol penetrate through the skin, the corresponding skin part becomes brighter. Similar results were also found with other three solvents. Figure 7 (B) shows the time-dependent penetration curves of four different solvents, it shows that alcohol has the best penetration of these four solvents, the second is DMSO, whilst ethylene glycol and glycerol do not penetrate through the skin very well. Conclusions Capacitive contact imaging can provide useful information for skin characterizations. The shapes of the capacitive contacting imaging occlusion curves can be related to skin conditions, and different types of skin damages have different shapes of occlusion curves. Through calibration, we can get a linear, absolute, electric permittivity measurement, and through absolute permittivity we can also get absolute water content, as well as solvent concentration in skin. By using video mode, Epsilon can help us to do solvents penetration analysis. Acknowledgement  The authors would like to thank London South Bank University for the financial support. We also thank Biox Systems Ltd for the studentship support for C. Bontozoglou. References 1. Léveque, J.L. and Querleux, B. SkinChip, a new tool for investigating the skin surface in vivo. Skin Research and Technology 9, , (2003). 2. Batisse, D., Giron F. and Léveque J.L. Capacitance imaging of the skin surface. Skin Research and Technology 12, pp99-104, (2006). 3. Xiao P, Singh H, Zheng X, Berg EP, Imhof RE, In-vivo Skin Imaging For Hydration and Micro Relief Measurements. SCV Conference, Cardiff, UK, July 11-13, 2007. 4. Ou, X., Pan, W., Xiao, P., In vivo skin capacitive imaging analysis by using grey level co-occurrence matrix (GLCM), International Journal of Pharmaceutics, November 2013, ISSN , 5. W. Pan, X. Zhang, M.E. Lane and P. Xiao, "The Occlusion Effects in Capacitive Contact Imaging for In-vivo Skin Damage Assessments", International Journal of Cosmetic Science, 2015, 37, 395–400, doi: /ics 6. P. Xiao, C. Bontozoglou, Capacitive contact imaging for in-vivo hair and nail water content measurements, H&PC Today, Vol. 10(5), pp62-65, September/October 2015. 7. W. Pan, X. Zhang, E. Chirikhina and P. Xiao, "Skin Hydration Measurement Using Contact Imaging", SCC Showcase, New York, December , 2014. 8. Fujitsu Fingerprint Sensor,


Download ppt "Figure 1: The Epsilon Permittivity Imaging System."

Similar presentations


Ads by Google