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Labecka N, Szczepanczyk M, Mojumdar E, Sparr E, Björklund S. Unraveling UVB effects: Catalase activity and molecular alterations in the stratum corneum. J Colloid Interface Sci 2024; 666:176-188. [PMID: 38593652 DOI: 10.1016/j.jcis.2024.03.200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/25/2024] [Accepted: 03/29/2024] [Indexed: 04/11/2024]
Abstract
AIM Ultraviolet B (UVB) radiation can compromise the functionality of the skin barrier through various mechanisms. We hypothesize that UVB induce photochemical alterations in the components of the outermost layer of the skin, known as the stratum corneum (SC), and modulate its antioxidative defense mechanisms. Catalase is a well-known antioxidative enzyme found in the SC where it acts to scavenge reactive oxygen species. However, a detailed characterization of acute UVB exposure on the activity of native catalase in the SC is lacking. Moreover, the effects of UVB irradiation on the molecular dynamics and organization of the SC keratin and lipid components remain unclear. Thus, the aim of this work is to characterize consequences of UVB exposure on the structural and antioxidative properties of catalase, as well as on the molecular and global properties of the SC matrix surrounding the enzyme. EXPERIMENTS The effect of UVB irradiation on the catalase function is investigated by chronoamperometry with a skin covered oxygen electrode, which probes the activity of native catalase in the SC matrix. Circular dichroism is used to explore changes of the catalase secondary structure, and gel electrophoresis is used to detect fragmentation of the enzyme following the UVB exposure. UVB induced alterations of the SC molecular dynamics and structural features of the SC barrier, as well as its water sorption behavior, are investigated by a complementary set of techniques, including natural abundance 13C polarization transfer solid-state NMR, wide-angle X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and dynamic vapor sorption microbalance. FINDINGS The findings show that UVB exposure impairs the antioxidative function of catalase by deactivating both native catalase in the SC matrix and lyophilized catalase. However, UVB radiation does not alter the secondary structure of the catalase nor induce any observable enzyme fragmentation, which otherwise could explain deactivation of its function. NMR measurements on SC samples show a subtle increase in the molecular mobility of the terminal segments of the SC lipids, accompanied by a decrease in the mobility of lipid chain trans-gauche conformers after high doses of UVB exposure. At the same time, the NMR data suggest increased rigidity of the polypeptide backbone of the keratin filaments, while the molecular mobility of amino acid residues in random coil domains of keratin remain unaffected by UVB irradiation. The FTIR data show a consistent decrease in absorbance associated with lipid bond vibrations, relative to the main protein bands. Collectively, the NMR and FTIR data suggest a small modification in the composition of fluid and solid phases of the SC lipid and protein components after UVB exposure, unrelated to the hydration capacity of the SC tissue. To conclude, UVB deactivation of catalase is anticipated to elevate oxidative stress of the SC, which, when coupled with subtle changes in the molecular characteristics of the SC, may compromise the overall skin health and elevate the likelihood of developing skin disorders.
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Affiliation(s)
- Nikol Labecka
- Department of Biomedical Science, Malmö University, SE-205 06 Malmö, Sweden; Biofilms Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden; Division of Physical Chemistry, Chemistry Department, Lund University, SE-221 00 Lund, Sweden
| | - Michal Szczepanczyk
- Department of Biomedical Science, Malmö University, SE-205 06 Malmö, Sweden; Biofilms Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Enamul Mojumdar
- Department of Biomedical Science, Malmö University, SE-205 06 Malmö, Sweden; Biofilms Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden; Division of Physical Chemistry, Chemistry Department, Lund University, SE-221 00 Lund, Sweden; CR Competence AB, Box 124, 22100 Lund, Sweden
| | - Emma Sparr
- Division of Physical Chemistry, Chemistry Department, Lund University, SE-221 00 Lund, Sweden
| | - Sebastian Björklund
- Department of Biomedical Science, Malmö University, SE-205 06 Malmö, Sweden; Biofilms Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden.
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Ahn J, Nam YS. Assessing Barrier Function in Psoriasis and Cornification Models of Artificial Skin Using Non-Invasive Impedance Spectroscopy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2400111. [PMID: 38995098 DOI: 10.1002/advs.202400111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 06/16/2024] [Indexed: 07/13/2024]
Abstract
Reconstructed epidermal equivalents (REEs) consist of two distinct cell layers - the stratum corneum (SC) and the keratinocyte layer (KL). The interplay of these layers is particularly crucial in pruritic inflammatory disorders, like psoriasis, where a defective SC barrier is associated with immune dysregulation. However, independent evaluation of the skin barrier function of the SC and KL in REEs is highly challenging because of the lack of quantitative methodologies that do not disrupt the counter layer. Here, a non-invasive impedance spectroscopy technique is introduced for dissecting the distinct contributions of the SC and KL to overall skin barrier function without disrupting the structure. These findings, inferred from the impedance spectra, highlight the individual barrier resistances and maturation levels of each layer. Using an equivalent circuit model, a correlation between impedance parameters and specific skin layers, offering insights beyond traditional impedance methods that address full-thickness skin only is established. This approach successfully detects subtle changes, such as increased paracellular permeability due to mild irritants and the characterization of an immature SC in psoriatic models. This research has significant implications, paving the way for detailed mechanistic investigations and fostering the development of therapies for skin irritation and inflammatory disorders.
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Affiliation(s)
- Jaehwan Ahn
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Yoon Sung Nam
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
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Mousavi A, Rahimnejad M, Azimzadeh M, Akbari M, Savoji H. Recent advances in smart wearable sensors as electronic skin. J Mater Chem B 2023; 11:10332-10354. [PMID: 37909384 DOI: 10.1039/d3tb01373a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Flexible and multifunctional electronic devices and soft robots inspired by human organs, such as skin, have many applications. However, the emergence of electronic skins (e-skins) or textiles in biomedical engineering has made a great revolution in a myriad of people's lives who suffer from different types of diseases and problems in which their skin and muscles lose their appropriate functions. In this review, recent advances in the sensory function of the e-skins are described. Furthermore, we have categorized them from the sensory function perspective and highlighted their advantages and limitations. The categories are tactile sensors (including capacitive, piezoresistive, piezoelectric, triboelectric, and optical), temperature, and multi-sensors. In addition, we summarized the most recent advancements in sensors and their particular features. The role of material selection and structure in sensory function and other features of the e-skins are also discussed. Finally, current challenges and future prospects of these systems towards advanced biomedical applications are elaborated.
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Affiliation(s)
- Ali Mousavi
- Institute of Biomedical Engineering, Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, QC, H3T 1J4, Canada.
- Research Center, Sainte-Justine University Hospital, Montreal, QC, H3T 1C5, Canada
- Montreal TransMedTech Institute, Montreal, QC, H3T 1J4, Canada
| | - Maedeh Rahimnejad
- Department of Cariology, Restorative Sciences, and Endodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Mostafa Azimzadeh
- Laboratory for Innovations in Micro Engineering (LiME), Department of Mechanical Engineering, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Mohsen Akbari
- Laboratory for Innovations in Micro Engineering (LiME), Department of Mechanical Engineering, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Houman Savoji
- Institute of Biomedical Engineering, Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, QC, H3T 1J4, Canada.
- Research Center, Sainte-Justine University Hospital, Montreal, QC, H3T 1C5, Canada
- Montreal TransMedTech Institute, Montreal, QC, H3T 1J4, Canada
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Sousa ASP, Noites A, Vilarinho R, Santos R. Long-Term Electrode-Skin Impedance Variation for Electromyographic Measurements. SENSORS (BASEL, SWITZERLAND) 2023; 23:8582. [PMID: 37896675 PMCID: PMC10610867 DOI: 10.3390/s23208582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/21/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023]
Abstract
This study aims to observe the evolution of the electrode-skin interface impedance of surface EMG electrodes over the time taken to determine the time of stabilization. Eight healthy subjects participated in the study. Electrode-skin impedance was evaluated in the rectus abdominal muscle every five minutes, over a total period of 50 min. A reduction of 13.23% in the impedance values was observed in minute 10 (p = 0.007), and a reduction of 9.02% was observed in minute 15 (p = 0.029). No statistically significant differences were observed in the other instants evaluated. The findings obtained in the present study demonstrate a decrease in electrode-skin impedance from minute 5 to minute 15, followed by a stabilization period with a low percentage of variation till minute 50.
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Affiliation(s)
- Andreia S. P. Sousa
- Center for Rehabilitation Research—Human Movement System (Re)habilitation Area, School of Health, Polytechnic of Porto, Rua Dr. António Bernardino de Almeida, 400, 4200-072 Porto, Portugal; (A.N.); (R.V.); (R.S.)
| | - Andreia Noites
- Center for Rehabilitation Research—Human Movement System (Re)habilitation Area, School of Health, Polytechnic of Porto, Rua Dr. António Bernardino de Almeida, 400, 4200-072 Porto, Portugal; (A.N.); (R.V.); (R.S.)
| | - Rui Vilarinho
- Center for Rehabilitation Research—Human Movement System (Re)habilitation Area, School of Health, Polytechnic of Porto, Rua Dr. António Bernardino de Almeida, 400, 4200-072 Porto, Portugal; (A.N.); (R.V.); (R.S.)
- FP-I3ID, Escola Superior de Saúde-Fernando Pessoa, 4200-253 Porto, Portugal
| | - Rubim Santos
- Center for Rehabilitation Research—Human Movement System (Re)habilitation Area, School of Health, Polytechnic of Porto, Rua Dr. António Bernardino de Almeida, 400, 4200-072 Porto, Portugal; (A.N.); (R.V.); (R.S.)
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Ehtiati K, Eiler J, Bochynska A, Nissen LL, Strøbech E, Nielsen LF, Thormann E. Skin and Artificial Skin Models in Electrical Sensing Applications. ACS APPLIED BIO MATERIALS 2023; 6:3033-3051. [PMID: 37552576 DOI: 10.1021/acsabm.3c00356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Skin electrical properties play a significant role in recording biopotentials by using electrophysiological sensors. To test and evaluate sensor systems, it is commonly accepted to employ artificial skin models due to complications associated with testing on living tissues. The first goal of this Review is to provide a systematic understanding of the relation between skin structure and skin electrochemical behavior at an appropriate depth for electrophysiological sensing applications through a focus on skin structure, electrochemical properties of skin, and theoretical models (equivalent circuits) representing skin electrochemical behavior. The second goal is to review artificial skin models mimicking the electrochemical properties of skin and to give suggestions for future studies on relevant skin models based on a comparison between the behavior of skin and that of artificial skin models. The Review aims to help the reader to analyze the relation between the structure, elements of the equivalent circuits, and the resulting impedance data for both skin and artificial skin models.
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Affiliation(s)
- Koosha Ehtiati
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Johannes Eiler
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | | | | | | | | | - Esben Thormann
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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Todorov A, Torah R, Ardern-Jones MR, Beeby SP. Electromagnetic Sensing Techniques for Monitoring Atopic Dermatitis-Current Practices and Possible Advancements: A Review. SENSORS (BASEL, SWITZERLAND) 2023; 23:3935. [PMID: 37112275 PMCID: PMC10144024 DOI: 10.3390/s23083935] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 03/29/2023] [Accepted: 04/04/2023] [Indexed: 06/19/2023]
Abstract
Atopic dermatitis (AD) is one of the most common skin disorders, affecting nearly one-fifth of children and adolescents worldwide, and currently, the only method of monitoring the condition is through an in-person visual examination by a clinician. This method of assessment poses an inherent risk of subjectivity and can be restrictive to patients who do not have access to or cannot visit hospitals. Advances in digital sensing technologies can serve as a foundation for the development of a new generation of e-health devices that provide accurate and empirical evaluation of the condition to patients worldwide. The goal of this review is to study the past, present, and future of AD monitoring. First, current medical practices such as biopsy, tape stripping and blood serum are discussed with their merits and demerits. Then, alternative digital methods of medical evaluation are highlighted with the focus on non-invasive monitoring using biomarkers of AD-TEWL, skin permittivity, elasticity, and pruritus. Finally, possible future technologies are showcased such as radio frequency reflectometry and optical spectroscopy along with a short discussion to provoke research into improving the current techniques and employing the new ones to develop an AD monitoring device, which could eventually facilitate medical diagnosis.
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Affiliation(s)
- Alexandar Todorov
- Centre of Flexible Electronics and E-Textiles, School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK
| | - Russel Torah
- Centre of Flexible Electronics and E-Textiles, School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK
| | - Michael R. Ardern-Jones
- Clinical Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 1DU, UK
| | - Steve P. Beeby
- Centre of Flexible Electronics and E-Textiles, School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK
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Morin M, Runnsjö A, Ruzgas T, Engblom J, Björklund S. Effects of storage conditions on permeability and electrical impedance properties of the skin barrier. Int J Pharm 2023; 637:122891. [PMID: 36997077 DOI: 10.1016/j.ijpharm.2023.122891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 03/31/2023]
Abstract
The aim of this study was to investigate the effect of various skin preservation protocols on in vitro drug permeation, epidermal-dermal drug distribution, and electrical impedance properties of skin membranes. Acyclovir (AC) and methyl salicylate (MS) were selected as model drugs due to their different physicochemical properties and skin metabolic profiles. In particular, AC is relatively hydrophilic (logP -1.8) and not expected to be affected by skin metabolism, while MS is relatively lipophilic (logP 2.5) and susceptible to metabolism, being a substrate for esterase residing in skin. Skin from pig ears was used and freshly excised into split-thickness membranes, which were divided and immediately stored at five different storage conditions: a) 4 °C overnight (fresh control), b) 4 °C for 4 days, c and d) -20 °C for 6 weeks and one year, respectively, and e) -80 °C for 6 weeks. Based on the combined results, general trends are observed showing that fresh skin is associated with lower permeation of both model drugs and higher skin membrane electrical resistance, as compared to the other storage conditions. Interestingly, in the case of fresh skin, significantly lower amounts of MS are detected in the epidermis and dermis compartments, implying higher levels of ester hydrolysis of MS (i.e., higher esterase activity). In line with this, the concentration of salicylic acid (SA) extracted from the dermis is significantly higher for fresh skin, as compared to the other storage conditions. Nevertheless, for all storage conditions, substantial amounts of SA are detected in the receptor medium, as well as in the epidermis and dermis, implying that esterase activity is maintained to some extent in all cases. For AC, which is not expected to be affected by skin metabolism, freeze storage (protocols c-e) is observed to result in higher accumulation of AC in the epidermis, as compared to the case of fresh skin, while the AC concentration in dermis is unaffected. These observations can be rationalized primarily by the observed lower permeability of fresh skin towards this hydrophilic substance. Finally, a strong correlation between AC permeation and electrical skin resistance is shown for individual skin membranes irrespective of storage condition, while the corresponding correlation for MS is inferior. On the other hand, a strong correlation is shown for individual membranes between MS permeation and electrical skin capacitance, while a similar correlation for AC is lower. The observed correlations between drug permeability and electrical impedance open up for standardizing in vitro data for improved analysis and comparisons between permeability results obtained with skin stored at different conditions.
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8
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Goyal K, Borkholder DA, Day SW. Dependence of Skin-Electrode Contact Impedance on Material and Skin Hydration. SENSORS (BASEL, SWITZERLAND) 2022; 22:8510. [PMID: 36366209 PMCID: PMC9656728 DOI: 10.3390/s22218510] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
Dry electrodes offer an accessible continuous acquisition of biopotential signals as part of current in-home monitoring systems but often face challenges of high-contact impedance that results in poor signal quality. The performance of dry electrodes could be affected by electrode material and skin hydration. Herein, we investigate these dependencies using a circuit skin-electrode interface model, varying material and hydration in controlled benchtop experiments on a biomimetic skin phantom simulating dry and hydrated skin. Results of the model demonstrate the contribution of the individual components in the circuit to total impedance and assist in understanding the role of electrode material in the mechanistic principle of dry electrodes. Validation was performed by conducting in vivo skin-electrode contact impedance measurements across ten normative human subjects. Further, the impact of the electrode on biopotential signal quality was evaluated by demonstrating an ability to capture clinically relevant electrocardiogram signals by using dry electrodes integrated into a toilet seat cardiovascular monitoring system. Titanium electrodes resulted in better signal quality than stainless steel electrodes. Results suggest that relative permittivity of native oxide of electrode material come into contact with the skin contributes to the interface impedance, and can lead to enhancement in the capacitive coupling of biopotential signals, especially in dry skin individuals.
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Affiliation(s)
- Krittika Goyal
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - David A. Borkholder
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Steven W. Day
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
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Wekre SL, Landsverk HD, Lautridou J, Hjelde A, Imbert JP, Balestra C, Eftedal I. Hydration status during commercial saturation diving measured by bioimpedance and urine specific gravity. Front Physiol 2022; 13:971757. [PMID: 36246118 PMCID: PMC9559868 DOI: 10.3389/fphys.2022.971757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
Excessive fluid loss triggered by hyperbaric pressure, water immersion and hot water suits causes saturation divers to be at risk of dehydration. Dehydration is associated with reductions in mental and physical performance, resulting in less effective work and an increased risk of work-related accidents. In this study we examined the hydration status of 11 male divers over 19 days of a commercial saturation diving campaign to a working depth of 74 m, using two non-invasive methods: Bioelectrical impedance analysis (BIA) and urine specific gravity (USG). Measurements were made daily before and after bell runs, and the BIA data was used to calculated total body water (TBW). We found that BIA and USG were weakly negatively correlated, probably reflecting differences in what they measure. TBW was significantly increased after bell runs for all divers, but more so for bellmen than for in-water divers. There were no progressing changes in TBW over the 19-day study period, indicating that the divers’ routines were sufficient for maintaining their hydration levels on short and long term.
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Affiliation(s)
- Stian Lande Wekre
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, NTNU Norwegian University of Science and Technology, Trondheim, Norway
- *Correspondence: Stian Lande Wekre,
| | - Halvor Dagssøn Landsverk
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Jacky Lautridou
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Astrid Hjelde
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Costantino Balestra
- Environmental and Occupational Physiology Laboratory, Haute Ecole Bruxelles-Brabant HE2B, Brussels, Belgium
- DAN Europe Research, Brussels, Belgium
| | - Ingrid Eftedal
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, NTNU Norwegian University of Science and Technology, Trondheim, Norway
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Goyal K, Borkholder DA, Day SW. A biomimetic skin phantom for characterizing wearable electrodes in the low-frequency regime. SENSORS AND ACTUATORS. A, PHYSICAL 2022; 340:113513. [PMID: 35493959 PMCID: PMC9053740 DOI: 10.1016/j.sna.2022.113513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Advances in the integration of wearable devices in our daily life have led to the development of new electrode designs for biopotential monitoring. Historically, the development and testing of wearable electrodes for the acquisition of biopotential signals has been empirical, relying on experiments on human volunteers. However, the lack of explicit control on human variables, the intra-, and inter-subject variability complicates the understanding of the performance of these wearable electrodes. Herein, phantom mimicking the electrical properties of the skin in the low-frequency range (1 Hz-1000 Hz), which has the potential to be used as a platform for controlled benchtop experiments for testing electrode functionality, is demonstrated. The fabricated phantom comprises two layers representing the deeper tissues and stratum corneum. The lower layer of the phantom mimicking deeper tissues was realized using polyvinyl alcohol cryogel (PVA-c) prepared with 0.9% W/W saline solution by a freeze-thaw technique. The properties of the upper layer representing the stratum corneum were simulated using a 100μm thick layer fabricated by spin-coating a mixture of polydimethylsiloxane (PDMS), 2.5% W/W carbon black (CB) for conductance, and 40% W/W barium titanate (BaTiO3) as a dielectric. The hydration of the stratum corneum was modeled in a controlled way by varying porosity of the phantom's upper layer. Impedance spectroscopy measurements were carried out to investigate the electrical performance of the fabricated phantom and validated against the impedance response obtained across a physiological skin impedance range of five human subjects. The results indicated that the Bode plot depicting the impedance response obtained on the phantom was found to lie in the human skin range. Moreover, it was observed that the change of porosity provides control over the hydration and the phantom can be tuned as per the skin ranges among different individuals. Also, the phantom was able to mimic the impact of dry and hydrated skin on a simulated ECG signal in the time domain. The developed skin phantom is affordable, fairly easy to manufacture, stable over time, and can be used as a platform for benchtop testing of new electrode designs.
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Affiliation(s)
- Krittika Goyal
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, 14623, USA
| | - David A. Borkholder
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, 14623, USA
| | - Steven W. Day
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY, 14623, USA
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Tuca AC, Bernardelli de Mattos I, Funk M, Winter R, Palackic A, Groeber-Becker F, Kruse D, Kukla F, Lemarchand T, Kamolz LP. Orchestrating the Dermal/Epidermal Tissue Ratio during Wound Healing by Controlling the Moisture Content. Biomedicines 2022; 10:biomedicines10061286. [PMID: 35740308 PMCID: PMC9219632 DOI: 10.3390/biomedicines10061286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 01/13/2023] Open
Abstract
A balanced and moist wound environment and surface increases the effect of various growth factors, cytokines, and chemokines, stimulating cell growth and wound healing. Considering this fact, we tested in vitro and in vivo water evaporation rates from the cellulose dressing epicitehydro when combined with different secondary dressings as well as the resulting wound healing efficacy in a porcine donor site model. The aim of this study was to evaluate how the different rates of water evaporation affected wound healing efficacy. To this end, epicitehydro primary dressing, in combination with different secondary dressing materials (cotton gauze, JELONET◊, AQUACEL® Extra ™, and OPSITE◊ Flexifix), was placed on 3 × 3 cm-sized dermatome wounds with a depth of 1.2 mm on the flanks of domestic pigs. The healing process was analyzed histologically and quantified by morphometry. High water evaporation rates by using the correct secondary dressing, such as cotton gauze, favored a better re-epithelialization in comparison with the low water evaporation resulting from an occlusive secondary dressing, which favored the formation of a new and intact dermal tissue that nearly fully replaced all the dermis that was removed during wounding. This newly available evidence may be of great benefit to clinical wound management.
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Affiliation(s)
- Alexandru-Cristian Tuca
- Department of Surgery, Division of Plastic, Aesthetic and Reconstructive Surgery, Medical University of Graz, 8036 Graz, Austria; (R.W.); (A.P.); (L.-P.K.)
- Correspondence: ; Tel.: +43-316-385-30742
| | - Ives Bernardelli de Mattos
- Department Tissue Engineering & Regenerative Medicine (TERM), University Hospital Würzburg, 97080 Würzburg, Germany; (I.B.d.M.); (F.G.-B.); (D.K.)
| | | | - Raimund Winter
- Department of Surgery, Division of Plastic, Aesthetic and Reconstructive Surgery, Medical University of Graz, 8036 Graz, Austria; (R.W.); (A.P.); (L.-P.K.)
| | - Alen Palackic
- Department of Surgery, Division of Plastic, Aesthetic and Reconstructive Surgery, Medical University of Graz, 8036 Graz, Austria; (R.W.); (A.P.); (L.-P.K.)
| | - Florian Groeber-Becker
- Department Tissue Engineering & Regenerative Medicine (TERM), University Hospital Würzburg, 97080 Würzburg, Germany; (I.B.d.M.); (F.G.-B.); (D.K.)
- Translational Center Regenerative Therapies, Fraunhofer Institute for Silicate Research ISC, 97080 Würzburg, Germany
| | - Daniel Kruse
- Department Tissue Engineering & Regenerative Medicine (TERM), University Hospital Würzburg, 97080 Würzburg, Germany; (I.B.d.M.); (F.G.-B.); (D.K.)
| | - Fabian Kukla
- TPL Path Labs GmbH, 79111 Freiburg, Germany; (F.K.); (T.L.)
| | | | - Lars-Peter Kamolz
- Department of Surgery, Division of Plastic, Aesthetic and Reconstructive Surgery, Medical University of Graz, 8036 Graz, Austria; (R.W.); (A.P.); (L.-P.K.)
- Joanneum Research Forschungsgesellschaft mbH, COREMED, 8036 Graz, Austria
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Berger A. Delta-5 ® oil, containing the anti-inflammatory fatty acid sciadonic acid, improves skin barrier function in a skin irritation model in healthy female subjects. Lipids Health Dis 2022; 21:40. [PMID: 35443694 PMCID: PMC9019283 DOI: 10.1186/s12944-022-01643-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/02/2022] [Indexed: 11/10/2022] Open
Abstract
Background Sciadonic acid (SA) is an anti-inflammatory fatty acid displacing arachidonic acid (ARA) from specific phospholipid pools, thus modulating downstream pro-inflammatory lipid mediators. Its novel anti-inflammatory actions have been studied in vitro, in pre-clinical models, and stemming from testimonials, after topical- and oral application. It has not been tested in a formal clinical study for topical benefits previously. Skin barrier layer was our focus as it has a critically important role in maintaining skin moisture balance. Methods Herein, forearm skin was left undamaged; or barrier layer was chemically-damaged with 2% sodium lauryl sulfate (SLS) for 24 h. SLS-damaged skin was left untreated or treated with Delta-5® oil containing 24% SA twice daily for 27 days. Barrier function was assessed by open chamber transepidermal water loss (TEWL) and skin surface impedance on days 0 (clear skin), -1 (1-day post-SLS), -2 (2-days post-SLS, 1-day post-Delta-5), -3, -7, and − 28. Results Relative to day 1, Delta-5 oil statistically significantly decreased TEWL vs. untreated damaged sites, on days 3 (125% more reduced), -7 (74% more reduced), and − 28 (69% more reduced). Decreases in TEWL following chemical damage indicates improved skin barrier repair and healing. Similar patterns were quantified for skin impedance. There was also reduced redness observed on days 3 and − 7 with Delta-5 oil vs. untreated SLS-damaged skin. Conclusions Delta-5 oil thus has anti-inflammatory potential in human skin, under controlled clinical conditions, to accelerate irritant-induced healing, and improve skin barrier function. Improvement in barrier function would benefit dermatitis, acne, eczema, and skin scarring. In normal skin, Delta-5 oil has potential to promote healthy, moisturized skin; and improve skin structure, elasticity, and firmness.
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Affiliation(s)
- Alvin Berger
- SciaEssentials, LLC and Sciadonics, Inc, 1161 Wayzata Blvd E Unit 30, MN, 55391, Wayzata, United States.
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13
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Kis N, Gunnarsson M, Berkó S, Sparr E. The effects of glycols on molecular mobility, structure, and permeability in stratum corneum. J Control Release 2022; 343:755-764. [PMID: 35150813 DOI: 10.1016/j.jconrel.2022.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 11/26/2022]
Abstract
The skin provides an attractive alternative to the conventional drug administration routes. Still, it comes with challenges as the upper layer of the skin, the stratum corneum (SC), provides an efficient barrier against permeation of most compounds. One way to overcome the skin barrier is to apply chemical permeation enhancers, which can modify the SC structure. In this paper, we investigated the molecular effect of three different types of glycols in SC: dipropylene glycol (diPG), propylene glycol (PG), and butylene glycol (BG). The aim is to understand how these molecules influence the molecular mobility and structure of the SC components, and to relate the molecular effects to the efficiency of these molecules as permeation enhancers. We used complementary experimental techniques, including natural abundance 13C NMR spectroscopy and wide-angle X-ray diffraction to characterize the molecular consequences of these compounds at different doses in SC at 97% RH humidity and 32 °C. In addition, we study the permeation enhancing effects of the same glycols in comparable conditions using Raman spectroscopy. Based on the results from NMR, we conclude that all three glycols cause increased mobility in SC lipids, and that the addition of glycols has an effect on the keratin filaments in similar manner as Natural Moisturizing Factor (NMF). The highest mobility of both lipids and amino acids can be reached with BG, which is followed by PG. It is also shown that one reaches an apparent saturation level for all three chemicals in SC, after which increased addition of the compound does not lead to further increase in the mobility of SC lipids or protein components. The examination with Raman mapping show that BG and PG give a significant permeation enhancement as compared to SC without any added glycol at corresponding conditions. Finally, we observe a non-monotonic response in permeation enhancement with respect to the concentration of glycols, where the highest concentration does not give the highest permeation. This is explained by the dehydration effects at highest glycol concentrations. In summary, we find a good correlation between the molecular effects of glycols on the SC lipid and protein mobility, and macroscopic permeation enhances of the same molecules.
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Affiliation(s)
- Nikolett Kis
- Institute of Pharmaceutical Technology and Regulatory Affairs, Faculty of Pharmacy, University of Szeged, 6720 Szeged, Hungary.
| | - Maria Gunnarsson
- Division of Physical Chemistry, Chemistry Department, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
| | - Szilvia Berkó
- Institute of Pharmaceutical Technology and Regulatory Affairs, Faculty of Pharmacy, University of Szeged, 6720 Szeged, Hungary.
| | - Emma Sparr
- Division of Physical Chemistry, Chemistry Department, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
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14
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Hydrogels and Cubic Liquid Crystals for Non-Invasive Sampling of Low-Molecular-Weight Biomarkers—An Explorative In Vivo Study. Pharmaceutics 2022; 14:pharmaceutics14020313. [PMID: 35214046 PMCID: PMC8879558 DOI: 10.3390/pharmaceutics14020313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/20/2022] [Accepted: 01/25/2022] [Indexed: 02/05/2023] Open
Abstract
The molecular composition of human skin is altered due to diseases, which can be utilized for non-invasive sampling of biomarkers and disease diagnostics. For this to succeed, it is crucial to identify a sampling formulation with high extraction efficiency and reproducibility. Highly hydrated skin is expected to be optimal for increased diffusion of low-molecular-weight biomarkers, enabling efficient extraction as well as enhanced reproducibility as full hydration represents a well-defined endpoint. Here, the aim was to explore water-based formulations with high water activities, ensuring satisfactory skin hydration, for non-invasive sampling of four analytes that may serve as potential biomarkers, namely tryptophan, tyrosine, phenylalanine, and kynurenine. The included formulations consisted of two hydrogels (chitosan and agarose) and two different liquid crystalline cubic phases based on the polar lipid glycerol monooleate, which were all topically applied for 2 h on 35 healthy subjects in vivo. The skin status of all sampling sites was assessed by electrical impedance spectroscopy and transepidermal water loss, enabling explorative correlations between biophysical properties and analyte abundancies. Taken together, all formulations resulted in the successful and reproducible collection of the investigated biomarkers. Still, the cubic phases had an extraction capacity that was approximately two times higher compared to the hydrogels.
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15
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Szczepanczyk M, Ruzgas T, Gullfot F, Gustafsson A, Björklund S. Catalase Activity in Keratinocytes, Stratum Corneum, and Defatted Algae Biomass as a Potential Skin Care Ingredient. Biomedicines 2021; 9:1868. [PMID: 34944684 PMCID: PMC8699009 DOI: 10.3390/biomedicines9121868] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/02/2021] [Accepted: 12/02/2021] [Indexed: 11/16/2022] Open
Abstract
The generation of reactive oxygen species presents a destructive challenge for the skin organ and there is a clear need to advance skin care formulations aiming at alleviating oxidative stress. The aim of this work was to characterize the activity of the antioxidative enzyme catalase in keratinocytes and in the skin barrier (i.e., the stratum corneum). Further, the goal was to compare the activity levels with the corresponding catalase activity found in defatted algae biomass, which may serve as a source of antioxidative enzymes, as well as other beneficial algae-derived molecules, to be employed in skin care products. For this, an oxygen electrode-based method was employed to determine the catalase activity and the apparent kinetic parameters for purified catalase, as well as catalase naturally present in HaCaT keratinocytes, excised stratum corneum samples collected from pig ears with various amounts of melanin, and defatted algae biomass from the diatom Phaeodactylum tricornutum. Taken together, this work illustrates the versatility of the oxygen electrode-based method for characterizing catalase function in samples with a high degree of complexity and enables the assessment of sample treatment protocols and comparisons between different biological systems related to the skin organ or algae-derived materials as a potential source of skin care ingredients for combating oxidative stress.
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Affiliation(s)
- Michal Szczepanczyk
- Department of Biomedical Science, Malmö University, 214 32 Malmö, Sweden; (M.S.); (T.R.); (A.G.)
- Biofilms-Research Center for Biointerfaces, Malmö University, 214 32 Malmö, Sweden
- Simris Alg AB, 276 50 Hammenhög, Sweden;
| | - Tautgirdas Ruzgas
- Department of Biomedical Science, Malmö University, 214 32 Malmö, Sweden; (M.S.); (T.R.); (A.G.)
- Biofilms-Research Center for Biointerfaces, Malmö University, 214 32 Malmö, Sweden
| | | | - Anna Gustafsson
- Department of Biomedical Science, Malmö University, 214 32 Malmö, Sweden; (M.S.); (T.R.); (A.G.)
- Biofilms-Research Center for Biointerfaces, Malmö University, 214 32 Malmö, Sweden
| | - Sebastian Björklund
- Department of Biomedical Science, Malmö University, 214 32 Malmö, Sweden; (M.S.); (T.R.); (A.G.)
- Biofilms-Research Center for Biointerfaces, Malmö University, 214 32 Malmö, Sweden
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16
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Abe Y, Nishizawa M. Electrical aspects of skin as a pathway to engineering skin devices. APL Bioeng 2021; 5:041509. [PMID: 34849444 PMCID: PMC8604566 DOI: 10.1063/5.0064529] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 09/27/2021] [Indexed: 02/07/2023] Open
Abstract
Skin is one of the indispensable organs for life. The epidermis at the outermost surface provides a permeability barrier to infectious agents, chemicals, and excessive loss of water, while the dermis and subcutaneous tissue mechanically support the structure of the skin and appendages, including hairs and secretory glands. The integrity of the integumentary system is a key for general health, and many techniques have been developed to measure and control this protective function. In contrast, the effective skin barrier is the major obstacle for transdermal delivery and detection. Changes in the electrical properties of skin, such as impedance and ionic activity, is a practical indicator that reflects the structures and functions of the skin. For example, the impedance that reflects the hydration of the skin is measured for quantitative assessment in skincare, and the current generated across a wound is used for the evaluation and control of wound healing. Furthermore, the electrically charged structure of the skin enables transdermal drug delivery and chemical extraction. This paper provides an overview of the electrical aspects of the skin and summarizes current advances in the development of devices based on these features.
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Affiliation(s)
- Yuina Abe
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Matsuhiko Nishizawa
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
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17
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Extraction of natural moisturizing factor from the stratum corneum and its implication on skin molecular mobility. J Colloid Interface Sci 2021; 604:480-491. [PMID: 34273783 DOI: 10.1016/j.jcis.2021.07.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 12/12/2022]
Abstract
The natural moisturizing factor (NMF) is a mixture of small water-soluble compounds present in the upper layer of the skin, stratum corneum (SC). Soaking of SC in water leads to extraction of the NMF molecules, which may influence the SC molecular properties and lead to brittle and dry skin. In this study, we investigate how the molecular dynamics in SC lipid and protein components are affected by the removal of the NMF compounds. We then explore whether the changes in SC components caused by NMF removal can be reversed by a subsequent addition of one single NMF component: urea, pyrrolidone carboxylic acid (PCA) or potassium lactate. Samples of intact SC were investigated using NMR, X-ray diffraction, infrared spectroscopy and sorption microbalance. It is shown that the removal of NMF leads to reduced molecular mobility in keratin filaments and SC lipids compared to untreated SC. When the complex NMF mixture is replaced by one single NMF component, the molecular mobility in both keratin filaments and lipids is regained. From this we propose a general relation between the molecular mobility in SC and the amount of polar solutes which does not appear specific to the precise chemical identify of the NMF compounds.
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18
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Hoang VC, Shafaat A, Jankovskaja S, Gomes VG, Ruzgas T. Franz cells for facile biosensor evaluation: A case of HRP/SWCNT-based hydrogen peroxide detection via amperometric and wireless modes. Biosens Bioelectron 2021; 191:113420. [PMID: 34182432 DOI: 10.1016/j.bios.2021.113420] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 06/01/2021] [Accepted: 06/05/2021] [Indexed: 12/26/2022]
Abstract
Reducing animal use in biosensor research requires broader use of in vitro methods. In this work, we present a novel application of Franz cells suitable for biosensor development and evaluation in vitro. The work describes how Franz cell can be equipped with electrodes enabling characterization of biosensors in close proximity to skin. As an example of a sensor, hydrogen peroxide biosensor was prepared based on horseradish peroxidase (HRP)/single-walled carbon nanotube (SWCNT)-modified textile. The electrode exhibited lower detection limit of 0.3 μM and sensitivity of 184 μA mM-1 cm-2. The ability of this biosensor to monitor H2O2 penetration through skin and dialysis membranes was evaluated in Franz cell setup in amperometric and wireless modes. The results also show that catalase activity present in skin is a considerable problem for epidermal sensing of H2O2. This work highlights opportunities and obstacles that can be addressed by assessment of biosensors in Franz cell setup before progressing to their testing in animals and humans.
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Affiliation(s)
- Van Chinh Hoang
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06, Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06, Malmö, Sweden; The University of Sydney, School of Chemical and Biomolecular Engineering, NSW, 2006, Australia
| | - Atefeh Shafaat
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06, Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06, Malmö, Sweden
| | - Skaidre Jankovskaja
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06, Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06, Malmö, Sweden
| | - Vincent G Gomes
- The University of Sydney, School of Chemical and Biomolecular Engineering, NSW, 2006, Australia.
| | - Tautgirdas Ruzgas
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06, Malmö, Sweden; Biofilms - Research Center for Biointerfaces, Malmö University, SE-205 06, Malmö, Sweden.
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19
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Ogunjimi AT, Lawson C, Carr J, Patel KK, Ferguson N, Brogden NK. Micropore Closure Rates following Microneedle Application at Various Anatomical Sites in Healthy Human Subjects. Skin Pharmacol Physiol 2021; 34:214-228. [PMID: 33910205 DOI: 10.1159/000515454] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/19/2021] [Indexed: 12/21/2022]
Abstract
INTRODUCTION The continuous availability of open micropores is crucial for a successful microneedle (MN) drug delivery strategy. However, micropore lifetime depends on intrinsic skin functional and anatomical characteristics, which vary significantly at different anatomical sites. OBJECTIVE This pilot study explored if differences exist in micropore closure timeframes at 3 anatomical sites - upper arm, volar forearm, and abdomen. METHODS Healthy subjects (n = 35) self-identifying as Asian (n = 9), Bi-/multiracial (n = 2), Black (n = 9), Latino (n = 6), and White (n = 9) completed the study. The upper arm, volar forearm, and abdomen were treated with MNs; skin impedance and transepidermal water loss (TEWL) were measured at baseline and post-MN to confirm micropore formation. Impedance was measured for 3 days to evaluate micropore lifetime. Measurements of L*, which quantifies the skin lightness/darkness, were made using a tristimulus colorimeter. Micropore lifetime was determined by comparing baseline and post-MN impedance measurements, and micropore closure half-life was predicted using mathematical modeling. RESULTS Post-MN increase in TEWL and decrease in impedance were significant (p < 0.05), confirming successful micropore formation at all anatomical sites. When data were analyzed according to subject self-identified racial/ethnic groups, the mean micropore closure time at the abdomen (63.09 ± 13.13 h) was longer than the upper arm (60.34 ± 14.69 h) and volar forearm (58.29 ± 16.76 h). The predicted micropore closure half-life at anatomical sites was the abdomen (25.86 ± 14.96 h) ≈ upper arm (23.69 ± 13.67 h) > volar forearm (20.2 ± 11.99 h). Differences were not statistically significant between groups. Objective categorization by L* showed that the darker skin may be associated with longer micropore closure time at the abdomen site. CONCLUSIONS Our results suggest that anatomical site of application may not be a source of significant variability in micropore closure time. These findings may help reduce the number of physiological parameters that need to be explicitly considered when developing drug products to support MN-assisted drug delivery strategies.
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Affiliation(s)
- Abayomi Tolulope Ogunjimi
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa College of Pharmacy, Iowa City, Iowa, USA
| | - Christine Lawson
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa College of Pharmacy, Iowa City, Iowa, USA
| | - Jamie Carr
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa College of Pharmacy, Iowa City, Iowa, USA
| | - Krishna Kumar Patel
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa College of Pharmacy, Iowa City, Iowa, USA
| | - Nkanyezi Ferguson
- Department of Dermatology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Nicole K Brogden
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa College of Pharmacy, Iowa City, Iowa, USA.,Department of Dermatology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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20
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Mojumdar EH, Sparr E. The effect of pH and salt on the molecular structure and dynamics of the skin. Colloids Surf B Biointerfaces 2021; 198:111476. [DOI: 10.1016/j.colsurfb.2020.111476] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/08/2020] [Accepted: 11/09/2020] [Indexed: 01/17/2023]
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21
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Jankovskaja S, Engblom J, Rezeli M, Marko-Varga G, Ruzgas T, Björklund S. Non-invasive skin sampling of tryptophan/kynurenine ratio in vitro towards a skin cancer biomarker. Sci Rep 2021; 11:678. [PMID: 33436784 PMCID: PMC7803776 DOI: 10.1038/s41598-020-79903-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 12/11/2020] [Indexed: 02/06/2023] Open
Abstract
The tryptophan to kynurenine ratio (Trp/Kyn) has been proposed as a cancer biomarker. Non-invasive topical sampling of Trp/Kyn can therefore serve as a promising concept for skin cancer diagnostics. By performing in vitro pig skin permeability studies, we conclude that non-invasive topical sampling of Trp and Kyn is feasible. We explore the influence of different experimental conditions, which are relevant for the clinical in vivo setting, such as pH variations, sampling time, and microbial degradation of Trp and Kyn. The permeabilities of Trp and Kyn are overall similar. However, the permeated Trp/Kyn ratio is generally higher than unity due to endogenous Trp, which should be taken into account to obtain a non-biased Trp/Kyn ratio accurately reflecting systemic concentrations. Additionally, prolonged sampling time is associated with bacterial Trp and Kyn degradation and should be considered in a clinical setting. Finally, the experimental results are supported by the four permeation pathways model, predicting that the hydrophilic Trp and Kyn molecules mainly permeate through lipid defects (i.e., the porous pathway). However, the hydrophobic indole ring of Trp is suggested to result in a small but noticeable relative increase of Trp diffusion via pathways across the SC lipid lamellae, while the shunt pathway is proposed to slightly favor permeation of Kyn relative to Trp.
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Affiliation(s)
- Skaidre Jankovskaja
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, 205 06, Malmö, Sweden
- Biofilms-Research Center for Biointerfaces, Malmö University, 205 06, Malmö, Sweden
| | - Johan Engblom
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, 205 06, Malmö, Sweden
- Biofilms-Research Center for Biointerfaces, Malmö University, 205 06, Malmö, Sweden
| | - Melinda Rezeli
- Clinical Protein Science and Imaging, Department of Biomedical Engineering, Lund University, Lund, Sweden
| | - György Marko-Varga
- Clinical Protein Science and Imaging, Department of Biomedical Engineering, Lund University, Lund, Sweden
| | - Tautgirdas Ruzgas
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, 205 06, Malmö, Sweden
- Biofilms-Research Center for Biointerfaces, Malmö University, 205 06, Malmö, Sweden
| | - Sebastian Björklund
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, 205 06, Malmö, Sweden.
- Biofilms-Research Center for Biointerfaces, Malmö University, 205 06, Malmö, Sweden.
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22
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Hallan SS, Sguizzato M, Drechsler M, Mariani P, Montesi L, Cortesi R, Björklund S, Ruzgas T, Esposito E. The Potential of Caffeic Acid Lipid Nanoparticulate Systems for Skin Application: In Vitro Assays to Assess Delivery and Antioxidant Effect. NANOMATERIALS 2021; 11:nano11010171. [PMID: 33445433 PMCID: PMC7826983 DOI: 10.3390/nano11010171] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 02/06/2023]
Abstract
The object of this study is a comparison between solid lipid nanoparticles and ethosomes for caffeic acid delivery through the skin. Caffeic acid is a potent antioxidant molecule whose cutaneous administration is hampered by its low solubility and scarce stability. In order to improve its therapeutic potential, caffeic acid has been encapsulated within solid lipid nanoparticles and ethosomes. The effect of lipid matrix has been evaluated on the morphology and size distribution of solid lipid nanoparticles and ethosomes loaded with caffeic acid. Particularly, morphology has been investigated by cryogenic transmission electron microscopy and small angle X-ray scattering, while mean diameters have been evaluated by photon correlation spectroscopy. The antioxidant power has been evaluated by the 2,2-diphenyl-1-picrylhydrazyl methodology. The influence of the type of nanoparticulate system on caffeic acid diffusion has been evaluated by Franz cells associated to the nylon membrane, while to evaluate caffeic acid permeation through the skin, an amperometric study has been conducted, which was based on a porcine skin-covered oxygen electrode. This apparatus allows measuring the O2 concentration changes in the membrane induced by polyphenols and H2O2 reaction in the skin. The antioxidative reactions in the skin induced by caffeic acid administered by solid lipid nanoparticles or ethosomes have been evaluated. Franz cell results indicated that caffeic acid diffusion from ethosomes was 18-fold slower with respect to solid lipid nanoparticles. The amperometric method evidenced the transdermal delivery effect of ethosome, indicating an intense antioxidant activity of caffeic acid and a very low response in the case of SLN. Finally, an irritation patch test conducted on 20 human volunteers demonstrated that both ethosomes and solid lipid nanoparticles can be safely applied on the skin.
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Affiliation(s)
- Supandeep Singh Hallan
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy; (S.S.H.); (M.S.)
- Biofilms—Research Center for Biointerfaces, Faculty of Health and Society, Malmö University, SE-20506 Malmö, Sweden;
| | - Maddalena Sguizzato
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy; (S.S.H.); (M.S.)
| | - Markus Drechsler
- Bavarian Polymerinstitute “Electron and Optical Microscopy”, University of Bayreuth, D-95440 Bayreuth, Germany;
| | - Paolo Mariani
- Department of Life and Environmental Sciences, Polytechnic University of Marche, I-60131 Ancona, Italy;
| | - Leda Montesi
- Department of Life Sciences and Biotechnology, University of Ferrara, I-44121 Ferrara, Italy;
| | - Rita Cortesi
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy; (S.S.H.); (M.S.)
- Correspondence: (R.C.); (T.R.); (E.E.); Tel.: +39-0532-455259 (R.C.); +46-40-6657431 (T.R.); +39-0532-455230 (E.E.)
| | - Sebastian Björklund
- Biofilms—Research Center for Biointerfaces, Faculty of Health and Society, Malmö University, SE-20506 Malmö, Sweden;
| | - Tautgirdas Ruzgas
- Biofilms—Research Center for Biointerfaces, Faculty of Health and Society, Malmö University, SE-20506 Malmö, Sweden;
- Correspondence: (R.C.); (T.R.); (E.E.); Tel.: +39-0532-455259 (R.C.); +46-40-6657431 (T.R.); +39-0532-455230 (E.E.)
| | - Elisabetta Esposito
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy; (S.S.H.); (M.S.)
- Correspondence: (R.C.); (T.R.); (E.E.); Tel.: +39-0532-455259 (R.C.); +46-40-6657431 (T.R.); +39-0532-455230 (E.E.)
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23
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Edwick DO, Hince DA, Rawlins JM, Wood FM, Edgar DW. Alternate Electrode Positions for the Measurement of Hand Volumes Using Bioimpedance Spectroscopy. Lymphat Res Biol 2020; 18:560-571. [DOI: 10.1089/lrb.2019.0078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Dale O. Edwick
- State Adult Burns Unit, Fiona Stanley Hospital, Murdoch, Australia
- School of Physiotherapy, The University of Notre Dame Australia, Fremantle, Australia
- Fiona Wood Foundation, Fiona Stanley Hospital, Murdoch, Australia
| | - Dana A. Hince
- Institute of Health Research, The University of Notre Dame Australia, Fremantle, Australia
| | - Jeremy M. Rawlins
- State Adult Burns Unit, Fiona Stanley Hospital, Murdoch, Australia
- Department of Plastic and Maxillofacial Surgery, Royal Perth Hospital, Perth, Australia
| | - Fiona M. Wood
- State Adult Burns Unit, Fiona Stanley Hospital, Murdoch, Australia
- Fiona Wood Foundation, Fiona Stanley Hospital, Murdoch, Australia
- Burn Injury Research Unit, The University of Western Australia, Nedlands, Australia
| | - Dale W. Edgar
- State Adult Burns Unit, Fiona Stanley Hospital, Murdoch, Australia
- Fiona Wood Foundation, Fiona Stanley Hospital, Murdoch, Australia
- Institute of Health Research, The University of Notre Dame Australia, Fremantle, Australia
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24
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Morin M, Ruzgas T, Svedenhag P, Anderson CD, Ollmar S, Engblom J, Björklund S. Skin hydration dynamics investigated by electrical impedance techniques in vivo and in vitro. Sci Rep 2020; 10:17218. [PMID: 33057021 PMCID: PMC7557913 DOI: 10.1038/s41598-020-73684-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/08/2020] [Indexed: 12/18/2022] Open
Abstract
Skin is easily accessible for transdermal drug delivery and also attractive for biomarker sampling. These applications are strongly influenced by hydration where elevated hydration generally leads to increased skin permeability. Thus, favorable transdermal delivery and extraction conditions can be easily obtained by exploiting elevated skin hydration. Here, we provide a detailed in vivo and in vitro investigation of the skin hydration dynamics using three techniques based on electrical impedance spectroscopy. Good correlation between in vivo and in vitro results is demonstrated, which implies that simple but realistic in vitro models can be used for further studies related to skin hydration (e.g., cosmetic testing). Importantly, the results show that hydration proceeds in two stages. Firstly, hydration between 5 and 10 min results in a drastic skin impedance change, which is interpreted as filling of superficial voids in skin with conducting electrolyte solution. Secondly, a subtle impedance change is observed over time, which is interpreted as leveling of the water gradient across skin leading to structural relaxation/changes of the macromolecular skin barrier components. With respect to transdermal drug delivery and extraction of biomarkers; 1 h of hydration is suggested to result in beneficial and stable conditions in terms of high skin permeability and extraction efficiency.
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Affiliation(s)
- Maxim Morin
- Biofilms - Research Center for Biointerfaces, Malmö University, Malmö, Sweden.,Department of Biomedical Science, Faculty of Health and Society, Malmö University, Malmö, Sweden
| | - Tautgirdas Ruzgas
- Biofilms - Research Center for Biointerfaces, Malmö University, Malmö, Sweden.,Department of Biomedical Science, Faculty of Health and Society, Malmö University, Malmö, Sweden
| | | | | | - Stig Ollmar
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Johan Engblom
- Biofilms - Research Center for Biointerfaces, Malmö University, Malmö, Sweden.,Department of Biomedical Science, Faculty of Health and Society, Malmö University, Malmö, Sweden
| | - Sebastian Björklund
- Biofilms - Research Center for Biointerfaces, Malmö University, Malmö, Sweden. .,Department of Biomedical Science, Faculty of Health and Society, Malmö University, Malmö, Sweden.
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25
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Ershad F, Thukral A, Yue J, Comeaux P, Lu Y, Shim H, Sim K, Kim NI, Rao Z, Guevara R, Contreras L, Pan F, Zhang Y, Guan YS, Yang P, Wang X, Wang P, Wu X, Yu C. Ultra-conformal drawn-on-skin electronics for multifunctional motion artifact-free sensing and point-of-care treatment. Nat Commun 2020; 11:3823. [PMID: 32732934 PMCID: PMC7393123 DOI: 10.1038/s41467-020-17619-1] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 05/21/2020] [Indexed: 11/09/2022] Open
Abstract
An accurate extraction of physiological and physical signals from human skin is crucial for health monitoring, disease prevention, and treatment. Recent advances in wearable bioelectronics directly embedded to the epidermal surface are a promising solution for future epidermal sensing. However, the existing wearable bioelectronics are susceptible to motion artifacts as they lack proper adhesion and conformal interfacing with the skin during motion. Here, we present ultra-conformal, customizable, and deformable drawn-on-skin electronics, which is robust to motion due to strong adhesion and ultra-conformality of the electronic inks drawn directly on skin. Electronic inks, including conductors, semiconductors, and dielectrics, are drawn on-demand in a freeform manner to develop devices, such as transistors, strain sensors, temperature sensors, heaters, skin hydration sensors, and electrophysiological sensors. Electrophysiological signal monitoring during motion shows drawn-on-skin electronics' immunity to motion artifacts. Additionally, electrical stimulation based on drawn-on-skin electronics demonstrates accelerated healing of skin wounds.
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Affiliation(s)
- Faheem Ershad
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Anish Thukral
- Department of Mechanical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Jiping Yue
- Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, 60637, USA
| | - Phillip Comeaux
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Yuntao Lu
- Materials Science and Engineering Program, University of Houston, Houston, TX, 77204, USA
| | - Hyunseok Shim
- Materials Science and Engineering Program, University of Houston, Houston, TX, 77204, USA
| | - Kyoseung Sim
- Department of Mechanical Engineering, University of Houston, Houston, TX, 77204, USA
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Nam-In Kim
- Materials Science and Engineering Program, University of Houston, Houston, TX, 77204, USA
| | - Zhoulyu Rao
- Materials Science and Engineering Program, University of Houston, Houston, TX, 77204, USA
| | - Ross Guevara
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Luis Contreras
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Fengjiao Pan
- Department of Mechanical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Yongcao Zhang
- Materials Science and Engineering Program, University of Houston, Houston, TX, 77204, USA
| | - Ying-Shi Guan
- Department of Mechanical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Pinyi Yang
- Department of Mechanical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Xu Wang
- Materials Science and Engineering Program, University of Houston, Houston, TX, 77204, USA
| | - Peng Wang
- Department of Mechanical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Xiaoyang Wu
- Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, 60637, USA
| | - Cunjiang Yu
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA.
- Department of Mechanical Engineering, University of Houston, Houston, TX, 77204, USA.
- Materials Science and Engineering Program, University of Houston, Houston, TX, 77204, USA.
- Department of Electrical and Computer Engineering, University of Houston, Houston, TX, 77204, USA.
- Texas Center for Superconductivity, University of Houston, Houston, TX, 77204, USA.
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26
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Sunny AI, Kallos E, Kosmas P, Rahman M, Koutsoupidou M, Cano-Garcia H, Thanou M, Rafique W, Lipscombe O, Kassanos P, Triantis I. Feasibility Experiments to Detect Skin Hydration Using a Bio-Impedance Sensor. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:6032-6035. [PMID: 31947221 DOI: 10.1109/embc.2019.8857470] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We present proof of concept experiment of a sensing method to detect skin hydration using a low-cost bio-impedance sensor. The sensing system is validated by testing its current output over frequencies between 1 kHz and 50 kHz and comparing measured values of impedance. A series of experiments with salt-water mixtures as well as a gelatin-based phantom were carried out to test the sensor's ability to detect small changes in impedance due to changes in water content. We also compared impedance measurements from the phantom to human skin to confirm that the manufactured phantoms can mimic skin properties successfully. Our experimental results show that the sensor can detect small changes in salt concentration and can capture the correlation between the impedance and skin hydration in a reliable manner.
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27
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Bal-Öztürk A, Miccoli B, Avci-Adali M, Mogtader F, Sharifi F, Çeçen B, Yaşayan G, Braeken D, Alarcin E. Current Strategies and Future Perspectives of Skin-on-a-Chip Platforms: Innovations, Technical Challenges and Commercial Outlook. Curr Pharm Des 2019; 24:5437-5457. [PMID: 30727878 DOI: 10.2174/1381612825666190206195304] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 02/02/2019] [Indexed: 01/09/2023]
Abstract
The skin is the largest and most exposed organ in the human body. Not only it is involved in numerous biological processes essential for life but also it represents a significant endpoint for the application of pharmaceuticals. The area of in vitro skin tissue engineering has been progressing extensively in recent years. Advanced in vitro human skin models strongly impact the discovery of new drugs thanks to the enhanced screening efficiency and reliability. Nowadays, animal models are largely employed at the preclinical stage of new pharmaceutical compounds development for both risk assessment evaluation and pharmacokinetic studies. On the other hand, animal models often insufficiently foresee the human reaction due to the variations in skin immunity and physiology. Skin-on-chips devices offer innovative and state-of-the-art platforms essential to overcome these limitations. In the present review, we focus on the contribution of skin-on-chip platforms in fundamental research and applied medical research. In addition, we also highlighted the technical and practical difficulties that must be overcome to enhance skin-on-chip platforms, e.g. embedding electrical measurements, for improved modeling of human diseases as well as of new drug discovery and development.
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Affiliation(s)
- Ayça Bal-Öztürk
- Department of Analytical Chemistry, Faculty of Pharmacy, İstinye University, 34010, Zeytinburnu, Istanbul, Turkey,Department of Stem Cell and Tissue Engineering, Institute of Health Sciences, Istinye University, 34010 Istanbul, Turkey
| | - Beatrice Miccoli
- Imec, Department of Life Sciences and Imaging, 3001 Heverlee, Belgium,Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Meltem Avci-Adali
- Department of Thoracic and Cardiovascular Surgery, University Hospital Tuebingen, Calwerstraße 7/1, 72076 Tuebingen, Germany
| | - Ferzaneh Mogtader
- Department of Stem Cell and Tissue Engineering, Institute of Health Sciences, Istinye University, 34010 Istanbul, Turkey,NanoBMT, Cyberpark, Bilkent 06800, Ankara, Turkey
| | - Fatemeh Sharifi
- Department of Mechanical Engineering, Sharif University of Technology, Tehran 11365-11155, Iran
| | - Berivan Çeçen
- Biomechanics Department, Institute of Health Science, Dokuz Eylul University, 35340, Inciraltı, Izmir, Turkey; Department of Pharmaceutical Technology, Faculty of Pharmacy, Marmara University, Istanbul, Turkey
| | - Gökçen Yaşayan
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Marmara University, 34668, Haydarpaşa, Istanbul, Turkey
| | - Dries Braeken
- Imec, Department of Life Sciences and Imaging, 3001 Heverlee, Belgium
| | - Emine Alarcin
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Marmara University, 34668, Haydarpaşa, Istanbul, Turkey
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28
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Ibrahim B, McMurray J, Jafari AR. A Wrist-Worn Strap with an Array of Electrodes for Robust Physiological Sensing. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2019; 2018:4313-4317. [PMID: 30441308 DOI: 10.1109/embc.2018.8513238] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Robust sensing is one of the main challenges for wearable physiological monitoring because of the high dependency on the placement of electrodes on the body, retaining suitable contact between electrodes and skin, and the effect of motion artifacts. In this paper, we present a wrist-worn strap that includes a 2-D array of 48 miniature electrodes covering the bottom side of the wrist with good contact with the skin. Good skin contact directly impacts the sensing robustness. The array provides local measurements between adjacent electrodes that span the whole bottom side of the wrist with an area of 6.25×4.60 cm for robust sensing. The array allows for the automatic selection of the correct electrodes at the right location regardless of changes in the device placement on the wrist. In addition, using a large number of electrodes over a large area on the wrist ensures continuous contact of some electrodes with the skin during motion since all of the electrodes will not lose contact with the skin at the same time. We measured the electrode-skin impedance of the fabricated electrodes versus frequency and compared to other types of electrodes. We demonstrated good contact between all electrodes of the array and the skin by measuring electrode-skin impedance less than 10 k$\Omega$ at 16 kHz for all locations on the wrist strap. We also conducted measurements of impedance while the wearer was bending the wrist to validate the continuous contact of at least a subset of electrodes with the skin during such movements.
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29
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Bikson M, Esmaeilpour Z, Adair D, Kronberg G, Tyler WJ, Antal A, Datta A, Sabel BA, Nitsche MA, Loo C, Edwards D, Ekhtiari H, Knotkova H, Woods AJ, Hampstead BM, Badran BW, Peterchev AV. Transcranial electrical stimulation nomenclature. Brain Stimul 2019; 12:1349-1366. [PMID: 31358456 DOI: 10.1016/j.brs.2019.07.010] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 06/25/2019] [Accepted: 07/14/2019] [Indexed: 01/03/2023] Open
Abstract
Transcranial electrical stimulation (tES) aims to alter brain function non-invasively by applying current to electrodes on the scalp. Decades of research and technological advancement are associated with a growing diversity of tES methods and the associated nomenclature for describing these methods. Whether intended to produce a specific response so the brain can be studied or lead to a more enduring change in behavior (e.g. for treatment), the motivations for using tES have themselves influenced the evolution of nomenclature, leading to some scientific, clinical, and public confusion. This ambiguity arises from (i) the infinite parameter space available in designing tES methods of application and (ii) varied naming conventions based upon the intended effects and/or methods of application. Here, we compile a cohesive nomenclature for contemporary tES technologies that respects existing and historical norms, while incorporating insight and classifications based on state-of-the-art findings. We consolidate and clarify existing terminology conventions, but do not aim to create new nomenclature. The presented nomenclature aims to balance adopting broad definitions that encourage flexibility and innovation in research approaches, against classification specificity that minimizes ambiguity about protocols but can hinder progress. Constructive research around tES classification, such as transcranial direct current stimulation (tDCS), should allow some variations in protocol but also distinguish from approaches that bear so little resemblance that their safety and efficacy should not be compared directly. The proposed framework includes terms in contemporary use across peer-reviewed publications, including relatively new nomenclature introduced in the past decade, such as transcranial alternating current stimulation (tACS) and transcranial pulsed current stimulation (tPCS), as well as terms with long historical use such as electroconvulsive therapy (ECT). We also define commonly used terms-of-the-trade including electrode, lead, anode, and cathode, whose prior use, in varied contexts, can also be a source of confusion. This comprehensive clarification of nomenclature and associated preliminary proposals for standardized terminology can support the development of consensus on efficacy, safety, and regulatory standards.
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Affiliation(s)
- Marom Bikson
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA.
| | - Zeinab Esmaeilpour
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA.
| | - Devin Adair
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA
| | - Greg Kronberg
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA
| | - William J Tyler
- Arizona State University, School of Biological and Health Systems Engineering, Tempe, AZ, USA
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center Goettingen, Goettingen, Germany; Institute of Medical Psychology, Medical Faculty, Otto-v.-Guericke University of Magdeburg, Magdeburg, Germany
| | | | - Bernhard A Sabel
- Institute of Medical Psychology, Medical Faculty, Otto-v.-Guericke University of Magdeburg, Magdeburg, Germany
| | - Michael A Nitsche
- Leibniz Research Centre for Working Environment ant Human Factors, Dept. Psychology and Neurosciences, Dortmund, Germany; University Medical Hospital Bergmannsheil, Dept. Neurology, Bochum, Germany
| | - Colleen Loo
- School of Psychiatry & Black Dog Institute, University of New South Wales, Sydney, Australia
| | - Dylan Edwards
- Moss Rehabilitation Research Institute, Philadelphia, PA, USA; Edith Cowan University, Joondalup, Australia
| | | | - Helena Knotkova
- MJHS Institute for Innovation in Palliative Care, New York, NY, USA; Department of Family and Social Medicine, Albert Einstein College of Medicine, The Bronx, NY, USA
| | - Adam J Woods
- Center for Cognitive Aging and Memory, McKnight Brain Institute, Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Benjamin M Hampstead
- Mental Health Service, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA; Neuropsychology Section, Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
| | - Bashar W Badran
- Department of Psychiatry, Medical University of South Carolina, Charleston, SC, USA
| | - Angel V Peterchev
- Department of Psychiatry & Behavioral Sciences, Department of Biomedical Engineering, Department of Electrical & Computer Engineering, Department of Neurosurgery, Duke University, Durham, NC, USA
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30
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Li Y, Ma R, Wang X, Jin J, Wang H, Liu Z, Yin T. Tissue coefficient of bioimpedance spectrometry as an index to discriminate different tissues in vivo. Biocybern Biomed Eng 2019. [DOI: 10.1016/j.bbe.2019.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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31
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Hernández AR, Boutonnet M, Svensson B, Butler E, Lood R, Blom K, Vallejo B, Anderson C, Engblom J, Ruzgas T, Björklund S. New concepts for transdermal delivery of oxygen based on catalase biochemical reactions studied by oxygen electrode amperometry. J Control Release 2019; 306:121-129. [DOI: 10.1016/j.jconrel.2019.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 05/06/2019] [Accepted: 06/01/2019] [Indexed: 02/07/2023]
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32
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Tan ST, Winarto N, Dosan R, Aisyah PB. The Benefits Of Occlusive Dressings In Wound Healing. ACTA ACUST UNITED AC 2019. [DOI: 10.2174/1874372201913010027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
There are several types of wounds with their own healing properties. The latest innovation in wound management by using occlusive dressings can prevent infections, improve healing time and patient’s comfort. Occlusive dressings are often used as an immediate wound hygiene control and also prevent blood loss until debridement is performed. They are used to protect wounds and surrounding tissue from pathogens and other harmful materials. A good cover depends on the condition around the wound, the person's skills, and the injury's nature. In this article, we provide an insight into the types of polymer materials used clinically in wound dressing and underlying mechanisms between the biomaterial dressings and the body tissue.
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33
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The Effect of UVB Irradiation and Oxidative Stress on the Skin Barrier-A New Method to Evaluate Sun Protection Factor Based on Electrical Impedance Spectroscopy. SENSORS 2019; 19:s19102376. [PMID: 31126113 PMCID: PMC6566889 DOI: 10.3390/s19102376] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/16/2019] [Accepted: 05/21/2019] [Indexed: 11/16/2022]
Abstract
Sunlight is vital for several biochemical processes of the skin organ. However, acute or chronic exposure to ultraviolet radiation (UVR) has several harmful effects on the skin structure and function, especially in the case of the failing function of antioxidative enzymes, which may lead to substantial tissue damage due to the increased presence of reactive oxygen species (ROS). The aim of this work was to investigate the combined effect of ultraviolet B (UVB) irradiation and oxidative stress on the skin barrier integrity. For this, we employed electrical impedance spectroscopy (EIS) to characterize changes of the electrical properties of excised pig skin membranes after various exposure conditions of UVB irradiation, oxidative stress, and the inhibition of antioxidative enzymatic processes. The oxidative stress was regulated by adding hydrogen peroxide (H2O2) as a source of ROS, while sodium azide (NaN3) was used as an inhibitor of the antioxidative enzyme catalase, which is naturally present throughout the epidermis. By screening for the combined effect of UVB and oxidative stress on the skin membrane electrical properties, we developed a new protocol for evaluating these parameters in a simple in vitro setup. Strikingly, the results show that exposure to extreme UVB irradiation does not affect the skin membrane resistance, implying that the skin barrier remains macroscopically intact. Likewise, exposure to only oxidative stress conditions, without UVB irradiation, does not affect the skin membrane resistance. In contrast to these observations, the combination of UVB irradiation and oxidative stress conditions results in a drastic decrease of the skin membrane resistance, indicating that the integrity of the skin barrier is compromised. Further, the skin membrane effective capacitance remained more or less unaffected by UVB exposure, irrespective of simultaneous exposure of oxidative stress. The EIS results were concluded to be associated with clear signs of macroscopic tissue damage of the epidermis as visualized with microscopy after exposure to UVB irradiation under oxidative stress conditions. Finally, the novel methodology was tested by performing an assessment of cosmetic sunscreen formulations with varying sun protection factor (SPF), with an overall successful outcome, showing good correlation between SPF value and protection capacity in terms of skin resistance change. The results from this study allow for the development of new skin sensors based on EIS for the detection of skin tissue damage from exposure to UVB irradiation and oxidative stress and provide a new, more comprehensive methodology, taking into account both the influence of UVB irradiation and oxidative stress, for in vitro determination of SPF in cosmetic formulations.
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Ali A, Wahlgren M, Pedersen L, Engblom J. Will a water gradient in oral mucosa affect transbuccal drug absorption? J Drug Deliv Sci Technol 2018. [DOI: 10.1016/j.jddst.2018.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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35
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Mojumdar EH, Pham QD, Topgaard D, Sparr E. Skin hydration: interplay between molecular dynamics, structure and water uptake in the stratum corneum. Sci Rep 2017; 7:15712. [PMID: 29146971 PMCID: PMC5691061 DOI: 10.1038/s41598-017-15921-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/27/2017] [Indexed: 12/24/2022] Open
Abstract
Hydration is a key aspect of the skin that influences its physical and mechanical properties. Here, we investigate the interplay between molecular and macroscopic properties of the outer skin layer - the stratum corneum (SC) and how this varies with hydration. It is shown that hydration leads to changes in the molecular arrangement of the peptides in the keratin filaments as well as dynamics of C-H bond reorientation of amino acids in the protruding terminals of keratin protein within the SC. The changes in molecular structure and dynamics occur at a threshold hydration corresponding to ca. 85% relative humidity (RH). The abrupt changes in SC molecular properties coincide with changes in SC macroscopic swelling properties as well as mechanical properties in the SC. The flexible terminals at the solid keratin filaments can be compared to flexible polymer brushes in colloidal systems, creating long-range repulsion and extensive swelling in water. We further show that the addition of urea to the SC at reduced RH leads to similar molecular and macroscopic responses as the increase in RH for SC without urea. The findings provide new molecular insights to deepen the understanding of how intermediate filament organization responds to changes in the surrounding environment.
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Affiliation(s)
- Enamul Haque Mojumdar
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden.
| | - Quoc Dat Pham
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
| | - Daniel Topgaard
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
| | - Emma Sparr
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden.
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36
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Oliveira AL, Moore Z, O Connor T, Patton D. Accuracy of ultrasound, thermography and subepidermal moisture in predicting pressure ulcers: a systematic review. J Wound Care 2017; 26:199-215. [PMID: 28475447 DOI: 10.12968/jowc.2017.26.5.199] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Our aims were to: establish the clinical significance of ultrasound, thermography, photography and subepidermal moisture (SEM) measurement; determine the accuracy of ultrasound, thermography, photography and SEM measurement in detecting skin/tissue damage; determine the relative accuracy of one of these assessment methods over another; make recommendations for practice pertaining to assessment of early skin/tissue damage. METHOD The following databases, Cochrane Wounds Group Specialised Register, The Cochrane Central Register of Controlled Trials, Ovid MEDLINE, Ovid EMBASE, Elsevier version, EBSCO CINAHL, ClinicalTrials.gov , WHO International Clinical Trials Registry (ICTR) and The EU Clinical Trials Register were searched for terms including; thermography, ultrasound, subepidermal moisture, photograph and pressure ulcer. RESULTS We identified four SEM, one thermography and five ultrasound studies for inclusion in this review. Data analysis indicated that photography was not a method which allowed for the early prediction of PU presence. SEM values increased with increasing tissue damage, with the sacrum and the heels being the most common anatomical locations for the development of erythema and stage I PUs. Thermography identified temperature changes in tissues and skin that may give an indication of early PU development; however the data were not sufficiently robust. Ultrasound detected pockets of fluid/oedema at different levels of the skin that were comparable with tissue damage. Thus, SEM and ultrasound were the best methods for allowing a more accurate assessment of early skin/tissue damage. Using the EBL Critical Appraisal Tool the overall validities of the studies varied between 33.3-55.6%, meaning that there is potential for bias within all the included studies. All of the studies were situated at level IV, V and VII of the evidence pyramid. Although the methodological quality of the studies warrants consideration, these studies showed the potential that SEM and ultrasound have in early PU detection. CONCLUSION SEM and ultrasound are promising in the detection and prediction of early tissue damage and PU presence. However, these methods should be further studied to clarify their potential for use more widely in PU prevention strategies.
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Affiliation(s)
- A L Oliveira
- Royal College of Surgeons in Ireland Dublin, Dublin Ireland
| | - Z Moore
- Royal College of Surgeons in Ireland Dublin, Dublin Ireland
| | - T O Connor
- Royal College of Surgeons in Ireland Dublin, Dublin Ireland
| | - D Patton
- Royal College of Surgeons in Ireland Dublin, Dublin Ireland
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37
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Electrochemical monitoring of native catalase activity in skin using skin covered oxygen electrode. Biosens Bioelectron 2017; 93:9-13. [DOI: 10.1016/j.bios.2017.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 12/20/2016] [Accepted: 01/02/2017] [Indexed: 11/17/2022]
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38
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Yao S, Myers A, Malhotra A, Lin F, Bozkurt A, Muth JF, Zhu Y. A Wearable Hydration Sensor with Conformal Nanowire Electrodes. Adv Healthc Mater 2017; 6. [PMID: 28128888 DOI: 10.1002/adhm.201601159] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/09/2016] [Indexed: 11/07/2022]
Abstract
A wearable skin hydration sensor in the form of a capacitor is demonstrated based on skin impedance measurement. The capacitor consists of two interdigitated or parallel electrodes that are made of silver nanowires (AgNWs) in a polydimethylsiloxane (PDMS) matrix. The flexible and stretchable nature of the AgNW/PDMS electrode allows conformal contact to the skin. The hydration sensor is insensitive to the external humidity change and is calibrated against a commercial skin hydration system on an artificial skin over a wide hydration range. The hydration sensor is packaged into a flexible wristband, together with a network analyzer chip, a button cell battery, and an ultralow power microprocessor with Bluetooth. In addition, a chest patch consisting of a strain sensor, three electrocardiography electrodes, and a skin hydration sensor is developed for multimodal sensing. The wearable wristband and chest patch may be used for low-cost, wireless, and continuous monitoring of skin hydration and other health parameters.
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Affiliation(s)
- Shanshan Yao
- Department of Mechanical and Aerospace Engineering North Carolina State University Raleigh NC 27695 USA
| | - Amanda Myers
- Department of Mechanical and Aerospace Engineering North Carolina State University Raleigh NC 27695 USA
| | - Abhishek Malhotra
- Department of Electrical and Computer Engineering North Carolina State University Raleigh NC 27695 USA
| | - Feiyan Lin
- Department of Electrical and Computer Engineering North Carolina State University Raleigh NC 27695 USA
| | - Alper Bozkurt
- Department of Electrical and Computer Engineering North Carolina State University Raleigh NC 27695 USA
| | - John F. Muth
- Department of Electrical and Computer Engineering North Carolina State University Raleigh NC 27695 USA
| | - Yong Zhu
- Department of Mechanical and Aerospace Engineering North Carolina State University Raleigh NC 27695 USA
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Evenbratt H, Ström A. Phase behavior, rheology, and release from liquid crystalline phases containing combinations of glycerol monooleate, glyceryl monooleyl ether, propylene glycol, and water. RSC Adv 2017. [DOI: 10.1039/c7ra04249c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Quaternary phase diagram of the GMO/GME/PG and water system is determined, allowing for controlled phase transitions triggered by temperature or humidity.
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Affiliation(s)
- Hanne Evenbratt
- Department of Chemistry and Chemical Engineering
- Pharmaceutical Technology
- Chalmers University of Technology
- Gothenburg
- Sweden
| | - Anna Ström
- Department of Chemistry and Chemical Engineering
- Pharmaceutical Technology
- Chalmers University of Technology
- Gothenburg
- Sweden
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41
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Davies L, Chappell P, Melvin T. Modelling the effect of hydration on skin conductivity. Skin Res Technol 2016; 23:363-368. [PMID: 27873364 DOI: 10.1111/srt.12344] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND Electrical signals are recorded from and sent into the body via the skin in a number of applications. In practice, skin is often hydrated with liquids having different conductivities so a model was produced in order to determine the relationship between skin impedance and conductivity. METHODS A model representing the skin was subjected to a variety of electrical signals. The parts of the model representing the stratum corneum were given different conductivities to represent different levels of hydration. RESULTS The overall impedance and conductivity of the cells did not vary at frequencies below 40 kHz. Above 40 kHz, levels of increased conductivity caused the overall impedance to decrease. CONCLUSION The variation in impedance with conductivity between 5 and 50 mSm-1 can be modelled quadratically while variation in impedance with conductivity between 5 and 5000 mSm-1 can be modelled with a double exponential decay.
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Affiliation(s)
- L Davies
- Institute of Complex Systems and Simulation, University of Southampton, Southampton, UK.,Electronics and Computer Science, University of Southampton, Southampton, UK
| | - P Chappell
- Electronics and Computer Science, University of Southampton, Southampton, UK
| | - T Melvin
- Electronics and Computer Science, University of Southampton, Southampton, UK.,Optoelectronics Research Centre, University of Southampton, Southampton, UK
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De Guzman K, Morrin A. Screen-printed Tattoo Sensor towards the Non-invasive Assessment of the Skin Barrier. ELECTROANAL 2016. [DOI: 10.1002/elan.201600572] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Keana De Guzman
- School of Chemical Sciences; National Centre for Sensor Research; Insight Centre for Data Analytics; Dublin City University; Dublin 9 Ireland
| | - Aoife Morrin
- School of Chemical Sciences; National Centre for Sensor Research; Insight Centre for Data Analytics; Dublin City University; Dublin 9 Ireland
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Alves L, Medronho B, Antunes FE, Topgaard D, Lindman B. Dissolution state of cellulose in aqueous systems. 2. Acidic solvents. Carbohydr Polym 2016; 151:707-715. [DOI: 10.1016/j.carbpol.2016.06.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/25/2016] [Accepted: 06/02/2016] [Indexed: 10/21/2022]
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The effects of polar excipients transcutol and dexpanthenol on molecular mobility, permeability, and electrical impedance of the skin barrier. J Colloid Interface Sci 2016; 479:207-220. [DOI: 10.1016/j.jcis.2016.06.054] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/21/2016] [Accepted: 06/21/2016] [Indexed: 11/16/2022]
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Ousey K, Cutting KF, Rogers AA, Rippon MG. The importance of hydration in wound healing: reinvigorating the clinical perspective. J Wound Care 2016; 25:122, 124-30. [PMID: 26947692 DOI: 10.12968/jowc.2016.25.3.122] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Balancing skin hydration levels is important as any disruption in skin integrity will result in disturbance of the dermal water balance. The discovery that a moist environment actively supports the healing response when compared with a dry environment highlights the importance of water and good hydration levels for optimal healing. The benefits of 'wet' or 'hyper-hydrated' wound healing appear similar to those offered by moist over a dry environment. This suggests that the presence of free water may not be detrimental to healing, but any adverse effects of wound fluid on tissues is more likely related to the biological components contained within chronic wound exudate, for example elevated protease levels. Appropriate dressings applied to wounds must not only be able to absorb the exudate, but also retain this excess fluid together with its protease solutes, while concurrently preventing desiccation. This is particularly important in the case of chronic wounds where peri-wound skin barrier properties are compromised and there is increased permeation across the injured skin. This review discusses the importance of appropriate levels of hydration in skin, with a particular focus on the need for optimal hydration levels for effective healing. Declaration of interest: This paper was supported by Paul Hartmann Ltd. The authors have provided consultative services to Paul Hartmann Ltd.
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Affiliation(s)
- K Ousey
- School of Human and Health Sciences, Institute of Skin Integrity and Infection Prevention. University of Huddersfield, Queensgate, Huddersfield
| | | | | | - M G Rippon
- School of Human and Health Sciences, Institute of Skin Integrity and Infection Prevention. University of Huddersfield, Queensgate, Huddersfield
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Solmaz H, Dervisoglu S, Gulsoy M, Ulgen Y. Laser biostimulation of wound healing: bioimpedance measurements support histology. Lasers Med Sci 2016; 31:1547-1554. [DOI: 10.1007/s10103-016-2013-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 06/24/2016] [Indexed: 10/21/2022]
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Bulysheva AA, Burcus N, Lundberg C, Edelblute CM, Francis MP, Heller R. Recellularized human dermis for testing gene electrotransfer ex vivo. ACTA ACUST UNITED AC 2016; 11:035002. [PMID: 27121769 DOI: 10.1088/1748-6041/11/3/035002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gene electrotransfer (GET) is a proven and valuable tool for in vivo gene delivery to a variety of tissues such as skin, cardiac muscle, skeletal muscle, and tumors, with controllable gene delivery and expression levels. Optimizing gene expression is a challenging hurdle in preclinical studies, particularly for skin indications, due to differences in electrical conductivity of animal compared to human dermis. Therefore, the goal of this study was to develop an ex vivo model for GET using recellularized human dermis to more closely mimic human skin. Decellularized human dermis (DermACELL(®)) was cultured with human dermal fibroblasts and keratinocytes for 4 weeks. After one week of fibroblast culture, fibroblasts infiltrated and dispersed throughout the dermis. Air-liquid interface culture led to epithelial cell proliferation, stratification and terminal differentiation with distinct basal, spinous, granular and cornified strata. Firefly luciferase expression kinetics were evaluated after GET of recellularized constructs for testing gene delivery parameters to skin in vitro. Elevated luciferase expression persisted up to a week following GET compared to controls without electrotransfer. In summary, recellularized dermis structurally and functionally resembled native human skin in tissue histological organization and homeostasis, proving an effective 3D human skin model for preclinical gene delivery studies.
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Affiliation(s)
- Anna A Bulysheva
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
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Rippon M, Ousey K, Cutting K. Wound healing and hyper-hydration: a counterintuitive model. J Wound Care 2016; 25:68, 70-5. [DOI: 10.12968/jowc.2016.25.2.68] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- M.G. Rippon
- School of Human and Health Sciences, Institute of Skin Integrity and Infection Prevention. University of Huddersfield, Queensgate, Huddersfield
| | - K. Ousey
- School of Human and Health Sciences, Institute of Skin Integrity and Infection Prevention. University of Huddersfield, Queensgate, Huddersfield
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Saleem S, Rosén B, Engblom J, Björkman A. Improvement of hand sensibility resulting from application of anaesthetic cream on the forearm: importance of dose and time. HAND THERAPY 2015. [DOI: 10.1177/1758998315595824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Introduction A local anaesthetic cream, EMLA®, applied temporarily to the forearm can improve sensory functions in the hands, both in healthy individuals and in patients with nerve injury. The treatment concept is an example of guided plasticity where the dynamic capacity of the central nervous system is used for therapeutic purposes. However, the optimal dose and duration of the anaesthetic cream is not known and this is addressed here. Methods Sixty healthy volunteers participated in this experimental study. They were randomised to one of six groups of 10 and received either 10 g or 20 g of EMLA® on the volar part of the forearm for either 60, 90 or 120 min, respectively. Outcome measures were touch thresholds and discriminative touch in digits II and V. Results There was a statistically significant improvement in touch threshold as well as discriminative touch in all six groups. However, there were no statistically significant differences between the six different dose and duration combinations. Conclusions It is concluded that 10 g of EMLA® applied to the volar part of the forearm for 60 min may be adequate to induce improved hand sensibility.
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Affiliation(s)
- Shifa Saleem
- Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, Sweden
- Biofilms- Research Center for Biointerfaces, Malmö University, Sweden
| | - Birgitta Rosén
- Department of Hand Surgery, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Johan Engblom
- Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, Sweden
- Biofilms- Research Center for Biointerfaces, Malmö University, Sweden
| | - Anders Björkman
- Department of Hand Surgery, Skåne University Hospital, Lund University, Malmö, Sweden
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Electrochemical characterization of gelatinized starch dispersions: voltammetry and electrochemical impedance spectroscopy on platinum surface. Carbohydr Polym 2015; 124:8-16. [PMID: 25839788 DOI: 10.1016/j.carbpol.2015.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 02/04/2015] [Accepted: 02/04/2015] [Indexed: 10/24/2022]
Abstract
The electrochemical properties of gelatinized starch dispersions (GSD; 5% w/w) from different botanical sources were studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests over a platinum surface. The phenomenological modelling of EIS data using equivalent circuits indicated that after gelatinization the electrical resistance was determined mainly by the resistance of insoluble material (i.e., ghosts). Sonication of the GSD disrupted the ghost microstructure, and produced an increase in electrical conductivity by reducing the resistance of the insoluble material. The CV data showed three oxidation peaks at potentials where glucose solutions displayed oxidation waves. It is postulated that hydrolysis at the bulk and electrocatalyzed oxidation on the Pt-surface are reactions involved in the starch transformation. Starches peak intensity increased with the amylose content, suggesting that the amylose-rich matrix played an important role in the charge transfer in the electrolytic system.
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