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Modeling Stratum Corneum Swelling for the Optimization of Electrode-Based Skin Hydration Sensors. SENSORS 2021; 21:s21123986. [PMID: 34207803 PMCID: PMC8229638 DOI: 10.3390/s21123986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 12/02/2022]
Abstract
We present a novel computational model of the human skin designed to investigate dielectric spectroscopy electrodes for stratum corneum hydration monitoring. The multilayer skin model allows for the swelling of the stratum corneum, as well as the variations of the dielectric properties under several hydration levels. According to the results, the stratum corneum thickness variations should not be neglected. For high hydration levels, swelling reduces the skin capacitance in comparison to a fixed stratum corneum thickness model. In addition, different fringing-field electrodes are evaluated in terms of sensitivity to the stratum corneum hydration level. As expected, both conductance and capacitance types of electrodes are influenced by the electrode geometry and dimension. However, the sensitivity of the conductance electrodes is more affected by dimension changes than the capacitance electrode leading to potential design optimization.
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Maruyama Y, Kamata H, Watanabe S, Kita R, Shinyashiki N, Yagihara S. Electric-field penetration depth and dielectric spectroscopy observations of human skin. Skin Res Technol 2019; 26:255-262. [PMID: 31556189 PMCID: PMC7079190 DOI: 10.1111/srt.12788] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 09/02/2019] [Indexed: 12/02/2022]
Abstract
Background The dynamic behavior of water molecules remains an important subject for understanding human skin. The change in the dynamics of water molecules from those in bulk water can be effectively observed by dielectric spectroscopy. To study water in the human skin in vivo, non‐invasive and non‐destructive measurements are essential. Since many unknowns remain from previous research, in this report we employ a two‐layer dielectric model to evaluate the penetration depth of the electric field and use the results in measurements on human skin. Materials and Methods We used open‐ended coaxial probes with different diameters to perform time‐domain reflectometry (TDR) measurements for an acetone‐Teflon double‐layer model and for human skin from various parts of the body. Results The electric‐field penetration depth obtained from model measurements increases with the increasing outer diameter of open‐ended coaxial electrodes. For skin measurements, the relaxation strength corresponding to the water content shows a clear dependence on the epidermal thickness of the measured body parts. Conclusion We determined the depth distribution of the water content of skin from results of dielectric measurements obtained using electrodes with various electric‐field penetration depths. We found exponential decays with the thickness of the epidermis of each body part for several examinees. This study suggests an effective method for detailed evaluations of human skin.
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Affiliation(s)
- Yuko Maruyama
- Graduate School of Science and Technology, Tokai University, Hiratsuka, Kanagawa, Japan
| | - Hayato Kamata
- Graduate School of Science, Tokai University, Hiratsuka, Kanagawa, Japan
| | - Seiei Watanabe
- Graduate School of Science, Tokai University, Hiratsuka, Kanagawa, Japan
| | - Rio Kita
- Department of Physics, School of Science, Tokai University, Hiratsuka, Kanagawa, Japan
| | - Naoki Shinyashiki
- Department of Physics, School of Science, Tokai University, Hiratsuka, Kanagawa, Japan
| | - Shin Yagihara
- Department of Physics, School of Science, Tokai University, Hiratsuka, Kanagawa, Japan
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McLemore G, Toker S, Boone-Kukoyi Z, Ajifa H, Lansiquot C, Nwawulu C, Onyedum S, Kioko BM, Aslan K. Microwave Heating of Crystals with Gold Nanoparticles and Synovial Fluid under Synthetic Skin Patches. ACS OMEGA 2017; 2:5992-6002. [PMID: 28983527 PMCID: PMC5623947 DOI: 10.1021/acsomega.7b00816] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 09/06/2017] [Indexed: 05/22/2023]
Abstract
Gout is a disease with elusive treatment options. Reduction of the size of l-alanine crystals as a model crystal for gouty tophi with the use of a monomode solid-state microwave was examined as a possible therapeutic aid. The effect of microwave heating on l-alanine crystals in the presence of gold nanoparticles (Au NPs) in solution and synovial fluid (SF) in a plastic pouch through a synthetic skin patch was investigated. In this regard, three experimental paradigms were employed: Paradigm 1 includes the effect of variable microwave power (5-10 W) and variable heating time (5-60 s) and Au NPs in water (20 nm size, volume of 10 μL) in a plastic pouch (1 × 2 cm2 in size). Paradigm 2 includes the effect of a variable volume of 20 nm Au NPs in a variable volume of SF up to 100 μL in a plastic pouch at a constant microwave power (10 W) for 30 s. Paradigm 3 includes the effect of constant microwave power (10 W) and microwave heating time (30 s), constant volume of Au NPs (100 μL), and variable size of Au NPs (20-200 nm) placed in a plastic pouch through a synthetic skin patch. In these experiments, an average of 60-100% reduction in the size of an l-alanine crystal (initial size = 450 μm) without damage to the synthetic skin or increasing the temperature of the samples beyond the physiological range was reported.
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Affiliation(s)
- Gabrielle
L. McLemore
- Department
of Biology and Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States
| | - Salih Toker
- Department
of Biology and Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States
| | - Zainab Boone-Kukoyi
- Department
of Biology and Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States
| | - Hillary Ajifa
- Department
of Biology and Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States
| | - Carisse Lansiquot
- Department
of Biology and Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States
| | - Chinenye Nwawulu
- Department
of Biology and Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States
| | - Stanley Onyedum
- Department
of Biology and Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States
| | - Bridgit M. Kioko
- Department
of Biology and Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States
| | - Kadir Aslan
- Department
of Biology and Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, Maryland 21251, United States
- E-mail: . Phone: 1 443 885 2242 (K.A.)
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Wong TW. Electrical, magnetic, photomechanical and cavitational waves to overcome skin barrier for transdermal drug delivery. J Control Release 2014; 193:257-69. [DOI: 10.1016/j.jconrel.2014.04.045] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/21/2014] [Accepted: 04/23/2014] [Indexed: 01/17/2023]
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Huclova S, Baumann D, Talary MS, Fröhlich J. Sensitivity and specificity analysis of fringing-field dielectric spectroscopy applied to a multi-layer system modelling the human skin. Phys Med Biol 2011; 56:7777-93. [PMID: 22107754 DOI: 10.1088/0031-9155/56/24/007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The sensitivity and specificity of dielectric spectroscopy for the detection of dielectric changes inside a multi-layered structure is investigated. We focus on providing a base for sensing physiological changes in the human skin, i.e. in the epidermal and dermal layers. The correlation between changes of the human skin's effective permittivity and changes of dielectric parameters and layer thickness of the epidermal and dermal layers is assessed using numerical simulations. Numerical models include fringing-field probes placed directly on a multi-layer model of the skin. The resulting dielectric spectra in the range from 100 kHz up to 100 MHz for different layer parameters and sensor geometries are used for a sensitivity and specificity analysis of this multi-layer system. First, employing a coaxial probe, a sensitivity analysis is performed for specific variations of the parameters of the epidermal and dermal layers. Second, the specificity of this system is analysed based on the roots and corresponding sign changes of the computed dielectric spectra and their first and second derivatives. The transferability of the derived results is shown by a comparison of the dielectric spectra of a coplanar probe and a scaled coaxial probe. Additionally, a comparison of the sensitivity of a coaxial probe and an interdigitated probe as a function of electrode distance is performed. It is found that the sensitivity for detecting changes of dielectric properties in the epidermal and dermal layers strongly depends on frequency. Based on an analysis of the dielectric spectra, changes in the effective dielectric parameters can theoretically be uniquely assigned to specific changes in permittivity and conductivity. However, in practice, measurement uncertainties may degrade the performance of the system.
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Affiliation(s)
- Sonja Huclova
- Laboratory for Electromagnetic Fields and Microwave Electronics, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland
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Huclova S, Fröhlich J, Falco L, Dewarrat F, Talary MS, Vahldieck R. Validation of human skin models in the MHz region. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2009:4461-4. [PMID: 19964633 DOI: 10.1109/iembs.2009.5333820] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The human skin consists of several layers with distinct dielectric properties. Resolving the impact of changes in dielectric parameters of skin layers and predicting them allows for non-invasive sensing in medical diagnosis. So far no complete skin and underlying tissue model is available for this purpose in the MHz range. Focusing on this dispersiondominated frequency region multilayer skin models are investigated: First, containing homogeneous non-dispersive sublayers and second, with sublayers obtained from a three-phase Maxwell-Garnett mixture of shelled cell-like ellipsoids. Both models are numerically simulated using the Finite Element Method, a fringing field sensor on the top of the multilayer system serving as a probe. Furthermore, measurements with the sensor probing skin in vivo are performed. In order to validate the models the uppermost skin layer, the stratum corneum was i) included and ii) removed in models and measurements. It is found that only the Maxwell-Garnett mixture model can qualitatively reproduce the measured dispersion which still occurs without the stratum corneum and consequently, structural features of tissue have to be part of the model.
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Affiliation(s)
- Sonja Huclova
- Laboratory for Electromagnetic Fields and Microwave Electronics, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland.
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Kundu SK, Yagihara S, Yoshida M, Shibayama M. Microwave Dielectric Study of an Oligomeric Electrolyte Gelator by Time Domain Reflectometry. J Phys Chem B 2009; 113:10112-6. [PMID: 19572678 DOI: 10.1021/jp901043h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shyamal Kumar Kundu
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan, Department of Physics, School of Science, Tokai University, 1117 Kitakanane, Hiratsuka, Kanagawa 259-1292, Japan, and Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Shin Yagihara
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan, Department of Physics, School of Science, Tokai University, 1117 Kitakanane, Hiratsuka, Kanagawa 259-1292, Japan, and Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Masaru Yoshida
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan, Department of Physics, School of Science, Tokai University, 1117 Kitakanane, Hiratsuka, Kanagawa 259-1292, Japan, and Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Mitsuhiro Shibayama
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan, Department of Physics, School of Science, Tokai University, 1117 Kitakanane, Hiratsuka, Kanagawa 259-1292, Japan, and Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
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Hayashi Y, Miura N, Shinyashiki N, Yagihara S. Free water content and monitoring of healing processes of skin burns studied by microwave dielectric spectroscopyin vivo. Phys Med Biol 2005; 50:599-612. [PMID: 15773622 DOI: 10.1088/0031-9155/50/4/003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have investigated the dielectric properties of human skin in vivo at frequencies up to 10 GHz using a time-domain reflectometry method with open-ended coaxial probes. Since gamma-dispersion results from the reorientation of free water molecules, the free water content of skin is quantitatively determined by dielectric measurements. The free water content of finger skin increased by about 10% after soaking in 37 degrees C water for 30 min, and it systematically decreased again through the drying process, as expected. Thus this analytical method has been applied to the study of skin burns. The free water content of burned human cheek skin due to hydrofluoric acid was significantly lower than that of normal skin, and the burned skin recovered through the healing process. In the case of a human hand skin burn due to heat, although the free water content was almost the same as that of normal skin at the beginning, it decreased during the healing process for the first 10 days, then began to increase. Although the number of test subjects was one for each experiment, it was shown that free water content is a good indicator for evaluating skin health and can be well monitored by dielectric spectroscopy.
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Affiliation(s)
- Yoshihito Hayashi
- Department of Physics, Tokai University, Hiratsuka-shi, Kanagawa 259-1292, Japan
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Miura N, Yagihara S, Mashimo S. Microwave Dielectric Properties of Solid and Liquid Foods Investigated by Time-domain Reflectometry. J Food Sci 2003. [DOI: 10.1111/j.1365-2621.2003.tb09656.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Raicu V, Saibara T, Irimajiri A. Multifrequency method for dielectric monitoring of cold-preserved organs. Phys Med Biol 2000; 45:1397-407. [PMID: 10843112 DOI: 10.1088/0031-9155/45/5/321] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To answer a growing need for non-invasive monitoring of biological organs, we have developed an automated system capable of repeated dielectric measurements over the frequency range 10 kHz-100 MHz. Further, we propose a novel method of data analysis that may convert the acquired, individual dispersion curves into a diagram of the time course of specific phenomenological parameters, such as the characteristic frequency. By using this new procedure, unattended, long-term monitoring of temporal changes in the dielectric behaviour of excised liver lobes stored at 4 degrees C was successfully realized. The 'multifrequency' method presented here was definitely superior to the conventional 'fixed-frequency' method in providing reliable results.
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Affiliation(s)
- V Raicu
- Department of Physiology, Kochi Medical School, Japan.
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Marzec E, Wachal K. The electrical properties of leg skin in normal individuals and in patients with ischemia. BIOELECTROCHEMISTRY AND BIOENERGETICS (LAUSANNE, SWITZERLAND) 1999; 49:73-5. [PMID: 10619451 DOI: 10.1016/s0302-4598(99)00057-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Measurements of skin electrical admittance were performed on the leg in healthy controls and patients with ischemia. The experiments were carried out using sinusoidal wave voltage at seven frequencies from 100 Hz to 100 kHz applied using two electrodes. The character of the frequency dependencies of admittance for both groups arises from stratum corneum--in the frequencies up to 10 kHz, and the underlying tissue of skin, above this frequency. Legs change their passive electrical properties due to ischemia. The measured data are interpreted as cell membranes become more permeable and thus an efflux of intracellular electrolyte.
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Affiliation(s)
- E Marzec
- Department of Biophysics, Karol Marcinkowski University of Medical Sciences in Poznań, Poland.
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