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Zhou M, González PJ, Van Haasterecht L, Soylu A, Mihailovski M, Van Zuijlen P, Groot ML. Uniaxial mechanical stretch properties correlated with three-dimensional microstructure of human dermal skin. Biomech Model Mechanobiol 2024; 23:911-925. [PMID: 38324073 PMCID: PMC11101527 DOI: 10.1007/s10237-023-01813-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 12/30/2023] [Indexed: 02/08/2024]
Abstract
The intact and healthy skin forms a barrier to the outside world and protects the body from mechanical impact. The skin is a complex structure with unique mechano-elastic properties. To better direct the design of biomimetic materials and induce skin regeneration in wounds with optimal outcome, more insight is required in how the mechano-elastic properties emerge from the skin's main constituents, collagen and elastin fibers. Here, we employed two-photon excited autofluorescence and second harmonic generation microscopy to characterize collagen and elastin fibers in 3D in 24 human dermis skin samples. Through uniaxial stretching experiments, we derive uni-directional mechanical properties from resultant stress-strain curves, including the initial Young's modulus, elastic Young's modulus, maximal stress, and maximal and mid-strain values. The stress-strain curves show a large variation, with an average Young's modules in the toe and linear regions of 0.1 MPa and 21 MPa. We performed a comprehensive analysis of the correlation between the key mechanical properties with age and with microstructural parameters, e.g., fiber density, thickness, and orientation. Age was found to correlate negatively with Young's modulus and collagen density. Moreover, real-time monitoring during uniaxial stretching allowed us to observe changes in collagen and elastin alignment. Elastin fibers aligned significantly in both the heel and linear regions, and the collagen bundles engaged and oriented mainly in the linear region. This research advances our understanding of skin biomechanics and yields input for future first principles full modeling of skin tissue.
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Affiliation(s)
- Mengyao Zhou
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands.
| | - Patrick José González
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands
| | - Ludo Van Haasterecht
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands
- Burn Center and Department of Plastic, Reconstructive and Hand Surgery, Red Cross Hospital, Mozartstraat 201, 1962 AB, Beverwijk, The Netherlands
- Department of Plastic, Reconstructive and Hand Surgery, Amsterdam University Medical Center (UMC), Location Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Alperen Soylu
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands
| | - Maria Mihailovski
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands
| | - Paul Van Zuijlen
- Burn Center and Department of Plastic, Reconstructive and Hand Surgery, Red Cross Hospital, Mozartstraat 201, 1962 AB, Beverwijk, The Netherlands
- Department of Plastic, Reconstructive and Hand Surgery, Amsterdam University Medical Center (UMC), Location Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
- Pediatric Surgical Centre, Emma Children's Hospital, Amsterdam University Medical Center (UMC), Location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands
- Amsterdam Movement Sciences (AMS) Institute, Amsterdam University Medical Center (UMC), Location Vrije Universiteit Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands
| | - Marie Louise Groot
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands
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2
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Gallagher S, Josyula K, Rahul, Kruger U, Gong A, Song A, Eschelbach E, Crawford D, Pham T, Sweet R, Parsey C, Norfleet J, De S. Mechanical behavior of full-thickness burn human skin is rate-independent. Sci Rep 2024; 14:11096. [PMID: 38750077 PMCID: PMC11096406 DOI: 10.1038/s41598-024-61556-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 05/07/2024] [Indexed: 05/18/2024] Open
Abstract
Skin tissue is recognized to exhibit rate-dependent mechanical behavior under various loading conditions. Here, we report that the full-thickness burn human skin exhibits rate-independent behavior under uniaxial tensile loading conditions. Mechanical properties, namely, ultimate tensile stress, ultimate tensile strain, and toughness, and parameters of Veronda-Westmann hyperelastic material law were assessed via uniaxial tensile tests. Univariate hypothesis testing yielded no significant difference (p > 0.01) in the distributions of these properties for skin samples loaded at three different rates of 0.3 mm/s, 2 mm/s, and 8 mm/s. Multivariate multiclass classification, employing a logistic regression model, failed to effectively discriminate samples loaded at the aforementioned rates, with a classification accuracy of only 40%. The median values for ultimate tensile stress, ultimate tensile strain, and toughness are computed as 1.73 MPa, 1.69, and 1.38 MPa, respectively. The findings of this study hold considerable significance for the refinement of burn care training protocols and treatment planning, shedding new light on the unique, rate-independent behavior of burn skin.
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Grants
- W911NF-17-2-0022 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
- W911NF-17-2-0022 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
- W911NF-17-2-0022 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
- W911NF-17-2-0022 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
- W912CG-20-2-0004 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
- W912CG-20-2-0004 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
- W912CG-20-2-0004 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
- W912CG-20-2-0004 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
- W912CG-20-2-0004 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
- W912CG-20-2-0004 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
- W911NF-17-2-0022 U.S. Army Futures Command, Combat Capabilities Development Command Soldier Center STTC
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Affiliation(s)
- Samara Gallagher
- Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
- Center for Modeling, Simulation, and Imaging in Medicine, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Kartik Josyula
- Center for Modeling, Simulation, and Imaging in Medicine, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Rahul
- Center for Modeling, Simulation, and Imaging in Medicine, Rensselaer Polytechnic Institute, Troy, NY, USA.
| | - Uwe Kruger
- Center for Modeling, Simulation, and Imaging in Medicine, Rensselaer Polytechnic Institute, Troy, NY, USA
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Alex Gong
- Center for Research in Education and Simulation Technologies, University of Washington, Seattle, WA, USA
| | - Agnes Song
- Center for Research in Education and Simulation Technologies, University of Washington, Seattle, WA, USA
| | - Emily Eschelbach
- UW Medicine Regional Burn Center at Harborview Medical Center, University of Washington, Seattle, WA, USA
| | - David Crawford
- UW Medicine Regional Burn Center at Harborview Medical Center, University of Washington, Seattle, WA, USA
| | - Tam Pham
- UW Medicine Regional Burn Center at Harborview Medical Center, University of Washington, Seattle, WA, USA
| | - Robert Sweet
- Center for Research in Education and Simulation Technologies, University of Washington, Seattle, WA, USA
| | - Conner Parsey
- U.S. Army Combat Capabilities Development Command - Soldier Center, Simulation and Training Technology Center, Orlando, FL, USA
| | - Jack Norfleet
- U.S. Army Combat Capabilities Development Command - Soldier Center, Simulation and Training Technology Center, Orlando, FL, USA
| | - Suvranu De
- Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
- Center for Modeling, Simulation, and Imaging in Medicine, Rensselaer Polytechnic Institute, Troy, NY, USA
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
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Medina-Lombardero S, Bain C, Charlton L, Pellicoro A, Rocliffe H, Cash J, Reuben R, Crichton ML. The biomechanics of wounds at physiologically relevant levels: Understanding skin's stress-shielding effect for the quantitative assessment of healing. Mater Today Bio 2024; 25:100963. [PMID: 38312802 PMCID: PMC10835282 DOI: 10.1016/j.mtbio.2024.100963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 12/15/2023] [Accepted: 01/15/2024] [Indexed: 02/06/2024] Open
Abstract
Wounds are responsible for the decrease in quality of life of billions of people around the world. Their assessment relies on subjective parameters which often delays optimal treatments and results in increased healthcare costs. In this work, we sought to understand and quantify how wounds at different healing stages (days 1, 3, 7 and 14 post wounding) change the mechanical properties of the tissues that contain them, and how these could be measured at clinically relevant strain levels, as a step towards quantitative wound tracking technologies. To achieve this, we used digital image correlation and mechanical testing on a mouse model of wound healing to map the global and local tissue strains. We found no significant differences in the elastic and viscoelastic properties of wounded vs unwounded skin when samples were measured in bulk, presumably as these were masked by the protective mechanisms of skin, which redistributes the applied loads to mitigate high stresses and reduce tissue damage. By measuring local strain values and observing the distinct patterns they formed, it was possible to establish a connection between the healing phase of the tissue (determined by the time post-injury and the observed histological features) and the overall mechanical behaviour. Importantly, these parameters were measured from the surface of the tissue, using physiologically relevant strains without increasing the tissue's damage. Adaptations of these approaches for clinical use have the potential to aid in the identification of skin healing problems, such as excessive inflammation or lack of mechanical progression over time. An increase, decrease, or lack of change in the elasticity and viscoelasticity parameters, can be indicative of wound state, thus ultimately leading to improved diagnostic outcomes.
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Affiliation(s)
- Sara Medina-Lombardero
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
| | - Connor Bain
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
| | - Laura Charlton
- School of Engineering, University of Edinburgh, Edinburgh, EH9 3RF, United Kingdom
| | - Antonella Pellicoro
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, EH16 4TJ, United Kingdom
| | - Holly Rocliffe
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, EH16 4TJ, United Kingdom
| | - Jenna Cash
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, EH16 4TJ, United Kingdom
| | - Robert Reuben
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
| | - Michael L. Crichton
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
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4
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Garyfallogiannis K, Purohit PK, Bassani JL. Cracks in tensile-contracting and tensile-dilating poroelastic materials. INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES 2024; 286-287:112563. [PMID: 38130319 PMCID: PMC10732463 DOI: 10.1016/j.ijsolstr.2023.112563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Fibrous gels such as cartilage, blood clots, and carbon-nanotube-based sponges with absorbed oils suffer a reduction in volume by the expulsion of liquid under uniaxial tension, and this directly affects crack-tip fields and energy release rates. A continuum model is formulated for isotropic fibrous gels that exhibit a range of behaviors from volume increasing to volume decreasing in uniaxial tension by changing the ratio of two material parameters. The motion of liquid in the pores of such gels is modeled using poroelasticity. The direction of liquid fluxes around cracks is shown to depend on whether the gel locally increases or decreases in volume. The energy release rate for cracks is computed using a surface-independent integral and it is shown to have two contributions - one from the stresses in the solid network, and another from the flow of liquid. The contribution to the integral from liquid permeation tends to be negative when the gel exhibits volume decrease, which effectively is a crack shielding mechanism.
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Affiliation(s)
| | - Prashant K. Purohit
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John L. Bassani
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
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5
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Loffet EA, Durel JF, Gao J, Kam R, Lim H, Nerurkar NL. Elastic fibers define embryonic tissue stiffness to enable buckling morphogenesis of the small intestine. Biomaterials 2023; 303:122405. [PMID: 38000151 PMCID: PMC10842730 DOI: 10.1016/j.biomaterials.2023.122405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/22/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023]
Abstract
During embryonic development, tissues must possess precise material properties to ensure that cell-generated forces give rise to the stereotyped morphologies of developing organs. However, the question of how material properties are established and regulated during development remains understudied. Here, we aim to address these broader questions through the study of intestinal looping, a process by which the initially straight intestinal tube buckles into loops, permitting ordered packing within the body cavity. Looping results from elongation of the tube against the constraint of an attached tissue, the dorsal mesentery, which is elastically stretched by the elongating tube to nearly triple its length. This elastic energy storage allows the mesentery to provide stable compressive forces that ultimately buckle the tube into loops. Beginning with a transcriptomic analysis of the mesentery, we identified widespread upregulation of extracellular matrix related genes during looping, including genes related to elastic fiber deposition. Combining molecular and mechanical analyses, we conclude that elastin confers tensile stiffness to the mesentery, enabling its mechanical role in organizing the developing small intestine. These results shed light on the role of elastin as a driver of morphogenesis that extends beyond its more established role in resisting cyclic deformation in adult tissues.
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Affiliation(s)
- Elise A Loffet
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA
| | - John F Durel
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA
| | - Jenny Gao
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA
| | - Richard Kam
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA
| | - Hyunjee Lim
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA
| | - Nandan L Nerurkar
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA.
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6
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Elouneg A, Chambert J, Lejeune A, Lucot Q, Jacquet E, Bordas SPA. Anisotropic mechanical characterization of human skin by in vivo multi-axial ring suction test. J Mech Behav Biomed Mater 2023; 141:105779. [PMID: 36940583 DOI: 10.1016/j.jmbbm.2023.105779] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/10/2023] [Accepted: 03/12/2023] [Indexed: 03/17/2023]
Abstract
Human skin is a soft tissue behaving as an anisotropic material. The anisotropy emerges from the alignment of collagen fibers in the dermis, which causes the skin to exhibit greater stiffness in a certain direction, known as Langer's line. The importance of determining this anisotropy axis lies in assisting surgeons in making incisions that do not produce undesirable scars. In this paper, we introduce an open-source numerical framework, MARSAC (Multi-Axial Ring Suction for Anisotropy Characterization: https://github.com/aflahelouneg/MARSAC), adapted to a commercial device CutiScan CS 100® that applies a suction load on an annular section, causing a multi-axial stretch in the central zone, where in-plane displacements are captured by a camera. The presented framework receives inputs from a video file and converts them into displacement fields through Digital Image Correlation (DIC) technique. From the latter and based on an analytical model, the method assesses the anisotropic material parameters of human skin: Langer's line ϕ, and the elastic moduli E1 and E2 along the principal axes, providing that the Poisson's ratio is fixed. The pipeline was applied to a public data repository, https://search-data.ubfc.fr/femto/FR-18008901306731-2021-08-25_In-vivo-skin-anisotropy-dataset-for-a-young-man.html, containing 30 test series performed on a forearm of a Caucasian subject. As a result, the identified parameter averages, ϕˆ=40.9±8.2∘ and the anisotropy ratio E1ˆ/E2ˆ=3.14±1.60, were in accordance with the literature. The intra-subject analysis showed a reliable assessment of ϕ and E2. As skin anisotropy varies from site to site and from subject to subject, the novelty of the method consists in (i) an optimal utilization of CutiScan CS 100® probe to measure the Langer's line accurately and rapidly on small areas with a minimum diameter of 14mm, (ii) validation of an analytical model based on deformation ellipticity.
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Affiliation(s)
- A Elouneg
- Université de Franche-Comté, CNRS, institut FEMTO-ST, F-25000 Besançon, France; Institute of Computational Engineering and Sciences, Department of Engineering, Université du Luxembourg, Esch-sur-Alzette, Luxembourg
| | - J Chambert
- Université de Franche-Comté, CNRS, institut FEMTO-ST, F-25000 Besançon, France
| | - A Lejeune
- Université de Franche-Comté, CNRS, institut FEMTO-ST, F-25000 Besançon, France
| | - Q Lucot
- Université de Franche-Comté, CNRS, institut FEMTO-ST, F-25000 Besançon, France
| | - E Jacquet
- Université de Franche-Comté, CNRS, institut FEMTO-ST, F-25000 Besançon, France
| | - S P A Bordas
- Université de Franche-Comté, CNRS, institut FEMTO-ST, F-25000 Besançon, France; Institute of Computational Engineering and Sciences, Department of Engineering, Université du Luxembourg, Esch-sur-Alzette, Luxembourg.
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Dwivedi KK, Lakhani P, Sihota P, Tikoo K, Kumar S, Kumar N. The multiscale characterization and constitutive modeling of healthy and type 2 diabetes mellitus Sprague Dawley rat skin. Acta Biomater 2023; 158:324-346. [PMID: 36565785 DOI: 10.1016/j.actbio.2022.12.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/26/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
In type 2 diabetes mellitus (T2DM), elevated glucose level impairs the biochemistry of the skin which may result in alteration of its mechanical and structural properties. The several aspects of structural and mechanical changes in skin due to T2DM remain poorly understood. To fill these research gaps, we developed a non-obese T2DM rat (Sprague Dawley (SD)) model for investigating the effect of T2DM on the in vivo strain stress state, mechanical and structural properties of skin. In vivo strain and mechanical anisotropy of healthy and T2DM skin were measured using the digital imaging correlation (DIC) technique and DIC coupled bulge experiment, respectively. Fluorescence microscopy and histology were used to assess the collagen and elastin fibers microstructure whereas nanoscale structure was captured through atomic force microscopy (AFM). Based on the microstructural observations, skin was modeled as a multilayer membrane where in and out of plane distribution of collagen fibers and planar distribution of elastin fibers were cast in constitutive model. Further, the state of in vivo stresses of healthy and T2DM were measured using model parameters and in vivo strain in the constitutive model. The results showed that T2DM causes significant loss in in vivo stresses (p < 0.01) and increase in anisotropy (p < 0.001) of skin. These changes were found in good correlation with T2DM associated alteration in skin microstructure. Statistical analysis emphasized that increase in blood glucose concentration (HbA1c) was the main cause of impaired biomechanical properties of skin. The presented data in this study can help to understand the skin pathology and to simulate the skin related clinical procedures. STATEMENT OF SIGNIFICANCE: Our study is significant as it presents findings related to the effect of T2DM on the physiologic stress strain, structural and mechanical response of SD rat skin. In this study, we developed a non-obese T2DM SD rat model which mimics the phenotype of Asian type 2 diabetics (non-obese). Several structural and mechanical characterization techniques were explored for multiscale characterization of healthy and T2DM skin. Further, based on microstructural information, we presented the constitutive models that incorporate the real microstructure of skin. The presented results can be helpful to simulate the realistic mechanical response of skin during various clinical trials.
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Affiliation(s)
- Krashn Kr Dwivedi
- Department of Biomedical Engineering, Indian institute of Technology Ropar, India
| | - Piyush Lakhani
- Department of Mechanical Engineering, Indian institute of Technology Ropar, India
| | - Praveer Sihota
- Department of Mechanical Engineering, Indian institute of Technology Ropar, India
| | - Kulbhushan Tikoo
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Mohali, India
| | - Sachin Kumar
- Department of Mechanical Engineering, Indian institute of Technology Ropar, India.
| | - Navin Kumar
- Department of Biomedical Engineering, Indian institute of Technology Ropar, India; Department of Mechanical Engineering, Indian institute of Technology Ropar, India.
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8
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Mohizin A, Imran JH, Lee KS, Kim JK. Dynamic interaction of injected liquid jet with skin layer interfaces revealed by microsecond imaging of optically cleared ex vivo skin tissue model. J Biol Eng 2023; 17:15. [PMID: 36849998 PMCID: PMC9969392 DOI: 10.1186/s13036-023-00335-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 02/21/2023] [Indexed: 03/01/2023] Open
Abstract
BACKGROUND Needle-free jet injection (NFJI) systems enable a controlled and targeted delivery of drugs into skin tissue. However, a scarce understanding of their underlying mechanisms has been a major deterrent to the development of an efficient system. Primarily, the lack of a suitable visualization technique that could capture the dynamics of the injected fluid-tissue interaction with a microsecond range temporal resolution has emerged as a main limitation. A conventional needle-free injection system may inject the fluids within a few milliseconds and may need a temporal resolution in the microsecond range for obtaining the required images. However, the presently available imaging techniques for skin tissue visualization fail to achieve these required spatial and temporal resolutions. Previous studies on injected fluid-tissue interaction dynamics were conducted using in vitro media with a stiffness similar to that of skin tissue. However, these media are poor substitutes for real skin tissue, and the need for an imaging technique having ex vivo or in vivo imaging capability has been echoed in the previous reports. METHODS A near-infrared imaging technique that utilizes the optical absorption and fluorescence emission of indocyanine green dye, coupled with a tissue clearing technique, was developed for visualizing a NFJI in an ex vivo porcine skin tissue. RESULTS The optimal imaging conditions obtained by considering the optical properties of the developed system and mechanical properties of the cleared ex vivo samples are presented. Crucial information on the dynamic interaction of the injected liquid jet with the ex vivo skin tissue layers and their interfaces could be obtained. CONCLUSIONS The reported technique can be instrumental for understanding the injection mechanism and for the development of an efficient transdermal NFJI system as well.
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Affiliation(s)
- Abdul Mohizin
- grid.91443.3b0000 0001 0788 9816School of Mechanical Engineering, Kookmin University, 77 Jeongneung-Ro, Seongbuk-Gu, Seoul, 02707 Republic of Korea
| | - Jakir Hossain Imran
- grid.91443.3b0000 0001 0788 9816Department of Mechanical Engineering, Graduate School, Kookmin University, Seoul, 02707 Republic of Korea
| | - Kee Sung Lee
- grid.91443.3b0000 0001 0788 9816School of Mechanical Engineering, Kookmin University, 77 Jeongneung-Ro, Seongbuk-Gu, Seoul, 02707 Republic of Korea
| | - Jung Kyung Kim
- School of Mechanical Engineering, Kookmin University, 77 Jeongneung-Ro, Seongbuk-Gu, Seoul, 02707, Republic of Korea.
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Lecina-Tejero Ó, Pérez MÁ, García-Gareta E, Borau C. The rise of mechanical metamaterials: Auxetic constructs for skin wound healing. J Tissue Eng 2023; 14:20417314231177838. [PMID: 37362902 PMCID: PMC10285607 DOI: 10.1177/20417314231177838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 05/06/2023] [Indexed: 06/28/2023] Open
Abstract
Auxetic materials are known for their unique ability to expand/contract in multiple directions when stretched/compressed. In other words, they exhibit a negative Poisson's ratio, which is usually positive for most of materials. This behavior appears in some biological tissues such as human skin, where it promotes wound healing by providing an enhanced mechanical support and facilitating cell migration. Skin tissue engineering has been a growing research topic in recent years, largely thanks to the rapid development of 3D printing techniques and technologies. The combination of computational studies with rapid manufacturing and tailored designs presents a huge potential for the future of personalized medicine. Overall, this review article provides a comprehensive overview of the current state of research on auxetic constructs for skin healing applications, highlighting the potential of auxetics as a promising treatment option for skin wounds. The article also identifies gaps in the current knowledge and suggests areas for future research. In particular, we discuss the designs, materials, manufacturing techniques, and also the computational and experimental studies on this topic.
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Affiliation(s)
- Óscar Lecina-Tejero
- Multiscale in Mechanical and Biological Engineering, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Aragon, Spain
| | - María Ángeles Pérez
- Multiscale in Mechanical and Biological Engineering, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Aragon, Spain
- Aragon Institute for Health Research (IIS Aragon), Miguel Servet University Hospital, 50009 Zaragoza, Aragon, Spain
| | - Elena García-Gareta
- Multiscale in Mechanical and Biological Engineering, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Aragon, Spain
- Aragon Institute for Health Research (IIS Aragon), Miguel Servet University Hospital, 50009 Zaragoza, Aragon, Spain
- Division of Biomaterials & Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK
| | - Carlos Borau
- Multiscale in Mechanical and Biological Engineering, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Aragon, Spain
- Centro Universitario de la Defensa de Zaragoza, Zaragoza, 50090, Spain
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