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Blount H, Valenza A, Ward J, Caggiari S, Worsley PR, Filingeri D. The effect of female breast surface area on skin stiffness and tactile sensitivity at rest and following exercise in the heat. Exp Physiol 2024. [PMID: 39173060 DOI: 10.1113/ep091990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 07/29/2024] [Indexed: 08/24/2024]
Abstract
Female development includes significant morphological changes across the breast. Yet, whether differences in breast surface area (BrSA) modify breast skin stiffness and tactile sensitivity at rest and after exercise in the heat remain unclear. We investigated the relationship between BrSA and skin stiffness and tactile sensitivity in 20 young to middle-aged women (27 ± 8 years of age) of varying breast sizes (BrSA range: 147-502 cm2) at rest and after a submaximal run in a warm climatic chamber (32 C ${\mathrm{C}}$ ± 0 . 6 C ; ${\mathrm{0}}{\mathrm{.6C;}}$ 53% ± 1.7% relative humidity). Skin stiffness above and below the nipple and tactile sensitivity from the nipple down were measured. Associations between BrSA and both skin stiffness and tactile sensitivity at rest were determined via correlation analyses. Effects of exercise and test site were assessed by a two-way ANOVA. Skin stiffness was positively correlated with BrSA 3 cm above the areola edge (r = 0.61, P = 0.005) and at the superior areola border (r = 0.54, P = 0.016), but not below the nipple (P > 0.05). The area 3 cm below the areola was also significantly stiffer than all other test sites (P < 0.043). Tactile sensitivity did not vary with BrSA (P > 0.09), but it varied across the breast (i.e., the area 3 cm below the areola was more sensitive than the inferior areola edge; P = 0.018). Skin stiffness and tactile sensitivity across the breast decreased after exercise by ∼37% (P < 0.001) and ∼45% (P = 0.008), respectively. These findings expand our fundamental understanding of the mechanosensory properties of the female breast, and they could help to inform sportswear innovation to better meet the support needs of women of different breast sizes at rest and following exercise.
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Affiliation(s)
- Hannah Blount
- ThermosenseLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
| | - Alessandro Valenza
- ThermosenseLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
- Sport and Exercise Sciences Research Unit, SPPEFF Department, University of Palermo, Palermo, Italy
| | - Jade Ward
- ThermosenseLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
| | - Silvia Caggiari
- PressureLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
| | - Peter R Worsley
- PressureLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
| | - Davide Filingeri
- ThermosenseLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK
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Meretsky CR, Krumbach B, Popovich J, Ajebli M, Schiuma AT. Skin and Muscle Closure Techniques Following Large-Scale Osteosarcoma Removal: A Comparative Analysis. Cureus 2024; 16:e64258. [PMID: 39130915 PMCID: PMC11315368 DOI: 10.7759/cureus.64258] [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] [Accepted: 07/10/2024] [Indexed: 08/13/2024] Open
Abstract
Osteosarcoma (OS), the most prevalent form of bone cancer, typically arises in osteoblast cells responsible for generating new bone. The bone produced by these cancer cells is weaker compared to healthy bone. OS is an aggressive bone cancer that often requires extensive resection, leaving behind substantial soft tissue defects. Successful closure after tumor excision is critical for wound healing and postoperative recovery. However, the optimal approach varies depending on factors like defect size and location. After extensive resection of OS, restoring the integrity of the affected area demands careful closure of both the skin and underlying muscle. The appropriate closure technique depends on the size and location of the soft tissue defect. The main objective of this systematic review is to evaluate and compare different surgical techniques for closing skin and muscle layers following large-scale OS removal. Through a systematic review methodology, we conducted an extensive analysis of the existing body of literature on this topic, drawing from relevant research papers published over the past two decades. This allowed us to collectively evaluate and synthesize available data on the subject. This review found that negative pressure wound therapy (NPWT) and flap reconstruction are the main surgical approaches used to close skin and muscle following extensive OS resection, which commonly results in large soft tissue defects due to the nature of tumor removal. Furthermore, NPWT was the most widely used method for closing soft tissue defects after major OS removal, while flap reconstruction was also common when NPWT was not appropriate or the defect was too large. An integrated approach combining vacuum therapy, skin stretching, and occasional flaps seeks to primarily close large defects after OS resection through optimized healing and tension reduction to achieve the best postoperative results.
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Affiliation(s)
| | | | - Jay Popovich
- Internal Medicine, St. George's University School of Medicine, Great River, USA
| | - Mohammed Ajebli
- Biology Sciences, Moulay Ismail University, Faculty of Sciences and Technologies, Errachidia, MAR
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Ammam I, Guillermin A, Ouillon L, Vargiolu R, Perrot JL, Zahouani H. Coupling tensile test with LC-OCT and ultrasound imaging: investigation of the skin sublayers mechanical behaviour. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231712. [PMID: 39100155 PMCID: PMC11296144 DOI: 10.1098/rsos.231712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 03/15/2024] [Accepted: 05/06/2024] [Indexed: 08/06/2024]
Abstract
The skin is an envelope that covers the entire body. Nowadays, understanding and studying the mechanical, biological and sensory properties of the skin is essential, especially in dermatology and cosmetology. The in-depth study of the skin's mechanical behaviour is a highly intriguing challenge, enabling the differentiation of the behaviour of each layer. An extension device was developed to perform relaxation and extension tests to characterize the skin. The device has also been coupled with imaging tools (LC-OCT and ultrasound), allowing us to observe layer-by-layer deformations during the tests. Relaxation tests revealed significant skin anisotropy, as well as an influence of age and gender on skin viscoelastic parameters calculated from relaxation curves and a skin viscoelastic model. These tests also unveiled their ability to distinguish certain characteristic pathologies that alter the mechanical properties of the skin, such as scleroderma or heliodermatitis. Furthermore, the optical-mechanical coupling and deformation calculation through image analysis demonstrated that the skin layers exhibit distinct mechanical behaviours owing to their different structures. Finally, Poisson's ratio of the skin was obtained by calculating the deformation in two directions for each layer.
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Affiliation(s)
- Ianis Ammam
- Université de Lyon, ENISE, LTDS, UMR 5513 CNRS, 58 rue Jean Parot, Saint-Etienne Cedex 242023, France
| | - Amaury Guillermin
- Université de Lyon, ENISE, LTDS, UMR 5513 CNRS, 58 rue Jean Parot, Saint-Etienne Cedex 242023, France
| | - Lucas Ouillon
- Université de Lyon, ENISE, LTDS, UMR 5513 CNRS, 58 rue Jean Parot, Saint-Etienne Cedex 242023, France
| | - Roberto Vargiolu
- Université de Lyon, ENISE, LTDS, UMR 5513 CNRS, 58 rue Jean Parot, Saint-Etienne Cedex 242023, France
| | - Jean-Luc Perrot
- Dermatology Department, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Hassan Zahouani
- Université de Lyon, ENISE, LTDS, UMR 5513 CNRS, 58 rue Jean Parot, Saint-Etienne Cedex 242023, France
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Maikos JT, Chomack JM, Herlihy DV, Paglia DN, Wetterstrand C, O'Connor JP, Hyre MJ, Loan JP, D'Andrea SE. Quantifying Bone and Skin Movement in the Residual Limb-Socket Interface of Individuals With Transtibial Limb Loss Using Dynamic Stereo X-Ray: Protocol for a Lower Limb Loss Cadaver and Clinical Study. JMIR Res Protoc 2024; 13:e57329. [PMID: 38669065 PMCID: PMC11087852 DOI: 10.2196/57329] [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: 02/13/2024] [Revised: 02/29/2024] [Accepted: 03/04/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Relative motion between the residual limb and socket in individuals with transtibial limb loss can lead to substantial consequences that limit mobility. Although assessments of the relative motion between the residual limb and socket have been performed, there remains a substantial gap in understanding the complex mechanics of the residual limb-socket interface during dynamic activities that limits the ability to improve socket design. However, dynamic stereo x-ray (DSX) is an advanced imaging technology that can quantify 3D bone movement and skin deformation inside a socket during dynamic activities. OBJECTIVE This study aims to develop analytical tools using DSX to quantify the dynamic, in vivo kinematics between the residual limb and socket and the mechanism of residual tissue deformation. METHODS A lower limb cadaver study will first be performed to optimize the placement of an array of radiopaque beads and markers on the socket, liner, and skin to simultaneously assess dynamic tibial movement and residual tissue and liner deformation. Five cadaver limbs will be used in an iterative process to develop an optimal marker setup. Stance phase gait will be simulated during each session to induce bone movement and skin and liner deformation. The number, shape, size, and placement of each marker will be evaluated after each session to refine the marker set. Once an optimal marker setup is identified, 21 participants with transtibial limb loss will be fitted with a socket capable of being suspended via both elevated vacuum and traditional suction. Participants will undergo a 4-week acclimation period and then be tested in the DSX system to track tibial, skin, and liner motion under both suspension techniques during 3 activities: treadmill walking at a self-selected speed, at a walking speed 10% faster, and during a step-down movement. The performance of the 2 suspension techniques will be evaluated by quantifying the 3D bone movement of the residual tibia with respect to the socket and quantifying liner and skin deformation at the socket-residuum interface. RESULTS This study was funded in October 2021. Cadaver testing began in January 2023. Enrollment began in February 2024. Data collection is expected to conclude in December 2025. The initial dissemination of results is expected in November 2026. CONCLUSIONS The successful completion of this study will help develop analytical methods for the accurate assessment of residual limb-socket motion. The results will significantly advance the understanding of the complex biomechanical interactions between the residual limb and the socket, which can aid in evidence-based clinical practice and socket prescription guidelines. This critical foundational information can aid in the development of future socket technology that has the potential to reduce secondary comorbidities that result from complications of poor prosthesis load transmission. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) DERR1-10.2196/57329.
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Affiliation(s)
- Jason T Maikos
- Veterans Affairs New York Harbor Healthcare System, New York, NY, United States
| | - John M Chomack
- Veterans Affairs New York Harbor Healthcare System, New York, NY, United States
| | - David V Herlihy
- Narrows Institute for Biomedical Research and Education, Inc., Brooklyn, NY, United States
| | - David N Paglia
- Department of Orthopaedics, Rutgers-New Jersey Medical School, Newark, NJ, United States
| | - Charlene Wetterstrand
- Department of Orthopaedics, Rutgers-New Jersey Medical School, Newark, NJ, United States
| | - J Patrick O'Connor
- Department of Orthopaedics, Rutgers-New Jersey Medical School, Newark, NJ, United States
| | - Michael J Hyre
- Narrows Institute for Biomedical Research and Education, Inc., Brooklyn, NY, United States
| | | | - Susan E D'Andrea
- Department of Kinesiology, College of Health Sciences, University of Rhode Island, Kingston, RI, United States
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Lin G, Yihao X, Zhang X, You J, Wang H, Zheng R, Tian L, Guo J, Song Z, Fan F. Tunneled Paranasal Augmentation Using Diced Autologous Costal Cartilage in Asian Rhinoplasty: A Comparative Study. Facial Plast Surg 2024. [PMID: 38547925 DOI: 10.1055/a-2296-3105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2024] Open
Abstract
Due to the prevalence of anterior maxilla dysplasia in Asian population, paranasal concavity is a common accompaniment to low nose, but its impact on facial harmonization is often underestimated. A retrospective comparative study was conducted on patients diagnosed as low nose with paranasal concavity between June 2017 and June 2021, with a total of 56 patients followed up successfully. The control and observation groups were established according to whether the paranasal augmentation was performed. Demographic data were collected. Cosmetic enhancement was quantitatively evaluated by sagittal planimetry, establishing related anatomical landmarks and measuring columella base prominence (CBP) and alar base prominence (ABP). Subjective evaluation concluded the patient-reported satisfaction (FACE-Q-Rhinoplasty Module and Facial Appearance Module) and the third-party physician assessment (Global Aesthetic Improvement Scale, GAIS).Significant improvements in CBP and ABP were reported both in the control and the observation group (p < 0.01). In postoperative intergroup comparisons, the observation group was superior to the control group regarding ABP values (2.5 ± 0.75 degrees, p < 0.01), FACE-Q-Facial scores (7.49 ± 3.70, p < 0.05), and GAIS scores (p < 0.05). However, no statistical difference was found in CBP values and FACE-Q-Rhinoplasty scores. Paranasal augmentation-related complications included asymmetry of alar bases (6.9%) and facial or intraoral foreign body sensation (34.5%). This study affirmed that paranasal augmentation using diced costal cartilage in rhinoplasty is a safe procedure effective in remedying paranasal concavity and improving facial satisfaction. LEVEL OF EVIDENCE:: IV.
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Affiliation(s)
- Guangxian Lin
- Nasal Reconstruction Centre, Chinese Academy of Medical Sciences & Peking Union Medical College Plastic Surgery Hospital and Institute, Shijingshan District, China
| | - Xu Yihao
- Nasal Reconstruction Centre, Chinese Academy of Medical Sciences & Peking Union Medical College Plastic Surgery Hospital and Institute, Shijingshan District, China
| | - Xulong Zhang
- Nasal Reconstruction Centre, Chinese Academy of Medical Sciences & Peking Union Medical College Plastic Surgery Hospital and Institute, Shijingshan District, China
| | - Jianjun You
- Nasal Reconstruction Centre, Chinese Academy of Medical Sciences & Peking Union Medical College Plastic Surgery Hospital and Institute, Shijingshan District, China
| | - Huan Wang
- Nasal Reconstruction Centre, Chinese Academy of Medical Sciences & Peking Union Medical College Plastic Surgery Hospital and Institute, Shijingshan District, China
| | - Ruobing Zheng
- Nasal Reconstruction Centre, Chinese Academy of Medical Sciences & Peking Union Medical College Plastic Surgery Hospital and Institute, Shijingshan District, China
| | - Le Tian
- Nasal Reconstruction Centre, Chinese Academy of Medical Sciences & Peking Union Medical College Plastic Surgery Hospital and Institute, Shijingshan District, China
| | - Junsheng Guo
- Nasal Reconstruction Centre, Chinese Academy of Medical Sciences & Peking Union Medical College Plastic Surgery Hospital and Institute, Shijingshan District, China
| | - Zhen Song
- Nasal Reconstruction Centre, Chinese Academy of Medical Sciences & Peking Union Medical College Plastic Surgery Hospital and Institute, Shijingshan District, China
| | - Fei Fan
- Nasal Reconstruction Centre, Chinese Academy of Medical Sciences & Peking Union Medical College Plastic Surgery Hospital and Institute, Shijingshan District, China
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Liu X, Deng Y, Liang Z, Qiao D, Zhang W, Wang M, Li F, Liu J, Wu Y, Chen G, Liu Y, Tan W, Xing J, Huang W, Zhao D, Li Y. The alteration of the structure and macroscopic mechanical response of porcine patellar tendon by elastase digestion. Front Bioeng Biotechnol 2024; 12:1374352. [PMID: 38694621 PMCID: PMC11061363 DOI: 10.3389/fbioe.2024.1374352] [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: 01/22/2024] [Accepted: 04/01/2024] [Indexed: 05/04/2024] Open
Abstract
Background: The treatment of patellar tendon injury has always been an unsolved problem, and mechanical characterization is very important for its repair and reconstruction. Elastin is a contributor to mechanics, but it is not clear how it affects the elasticity, viscoelastic properties, and structure of patellar tendon. Methods: The patellar tendons from six fresh adult experimental pigs were used in this study and they were made into 77 samples. The patellar tendon was specifically degraded by elastase, and the regional mechanical response and structural changes were investigated by: (1) Based on the previous study of elastase treatment conditions, the biochemical quantification of collagen, glycosaminoglycan and total protein was carried out; (2) The patellar tendon was divided into the proximal, central, and distal regions, and then the axial tensile test and stress relaxation test were performed before and after phosphate-buffered saline (PBS) or elastase treatment; (3) The dynamic constitutive model was established by the obtained mechanical data; (4) The structural relationship between elastin and collagen fibers was analyzed by two-photon microscopy and histology. Results: There was no statistical difference in mechanics between patellar tendon regions. Compared with those before elastase treatment, the low tensile modulus decreased by 75%-80%, the high tensile modulus decreased by 38%-47%, and the transition strain was prolonged after treatment. For viscoelastic behavior, the stress relaxation increased, the initial slope increased by 55%, the saturation slope increased by 44%, and the transition time increased by 25% after enzyme treatment. Elastin degradation made the collagen fibers of patellar tendon become disordered and looser, and the fiber wavelength increased significantly. Conclusion: The results of this study show that elastin plays an important role in the mechanical properties and fiber structure stability of patellar tendon, which supplements the structure-function relationship information of patellar tendon. The established constitutive model is of great significance to the prediction, repair and replacement of patellar tendon injury. In addition, human patellar tendon has a higher elastin content, so the results of this study can provide supporting information on the natural properties of tendon elastin degradation and guide the development of artificial patellar tendon biomaterials.
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Affiliation(s)
- Xiaoyun Liu
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Yuping Deng
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Peking University Shenzhen Graduate School, Shenzhen, China
- Department of Orthopedics and Traumatology, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
| | - Zeyu Liang
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Dan Qiao
- Department of Pathology, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wentian Zhang
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- The School of Basic Medical Sciences, Fujian Medical University, Fujian, China
| | - Mian Wang
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Peking University Shenzhen Graduate School, Shenzhen, China
- Department of Orthopaedics, Pingshan General Hospital of Southern Medical University, Shenzhen, China
| | - Feifei Li
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jiannan Liu
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yaobing Wu
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Guangxin Chen
- Medical Image College, Mudanjiang Medical University, Mudanjiang, Heilongjiang, China
| | - Yan Liu
- Department of Anatomy, Gannan Healthcare Vocational College, Ganzhou, China
| | - Wenchang Tan
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Jian Xing
- Medical Image College, Mudanjiang Medical University, Mudanjiang, Heilongjiang, China
| | - Wenhua Huang
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Department of Orthopedics and Traumatology, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
- Guangdong Medical Innovation Platform for Translation of 3D Printing Application, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Dongliang Zhao
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Yanbing Li
- National Key Discipline of Human Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
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Campos T, Araújo R, Xavier J, Nguyễn Q, Dourado N, Morais J, Pereira F. Identification of Apple Fruit-Skin Constitutive Laws by Full-Field Methods Using Uniaxial Tensile Loading. MATERIALS (BASEL, SWITZERLAND) 2024; 17:700. [PMID: 38591566 PMCID: PMC10856416 DOI: 10.3390/ma17030700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 04/10/2024]
Abstract
The protective and preservative role of apple skin in maintaining the integrity of the fruit is well-known, with its mechanical behaviour playing a pivotal role in determining fruit storage capacity. This study employs a combination of experimental and numerical methodologies, specifically utilising the digital image correlation (DIC) technique. A specially devised inverse strategy is applied to evaluate the mechanical behaviour of apple skin under uniaxial tensile loading. Three apple cultivars were tested in this work: Malus domestica Starking Delicious, Malus pumila Rennet, and Malus domestica Golden Delicious. Stress-strain curves were reconstructed, revealing distinct variations in the mechanical responses among these cultivars. Yeoh's hyperelastic model was fitted to the experimental data to identify the coefficients capable of reproducing the non-linear deformation. The results suggest that apple skin varies significantly in composition and structure among the tested cultivars, as evidenced by differences in elastic properties and non-linear behaviour. These differences can significantly affect how fruit is handled, stored, and transported. Thus, the insights resulting from this research enable the development of mathematical models based on the mechanical behaviour of apple tissue, constituting important data for improvements in the economics of the agri-food industry.
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Affiliation(s)
- Teresa Campos
- CMEMS-UMINHO, Universidade do Minho, 4800-058 Guimarães, Portugal (N.D.)
- LABBELS–Associate Laboratory, 4800-058 Guimarães, Portugal
| | - Rafael Araújo
- CITAB/UTAD, Departamento de Engenharias, Quinta de Prados, 5001-801 Vila Real, Portugal (J.M.); (F.P.)
| | - José Xavier
- UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
- LASI, Intelligent Systems Associate Laboratory, 4800-058 Guimarães, Portugal
| | - Quyền Nguyễn
- 2C2T-Centro de Ciência e Tecnologia Têxtil, Universidade do Minho, 4800-058 Guimarães, Portugal
| | - Nuno Dourado
- CMEMS-UMINHO, Universidade do Minho, 4800-058 Guimarães, Portugal (N.D.)
- LABBELS–Associate Laboratory, 4800-058 Guimarães, Portugal
| | - José Morais
- CITAB/UTAD, Departamento de Engenharias, Quinta de Prados, 5001-801 Vila Real, Portugal (J.M.); (F.P.)
| | - Fábio Pereira
- CITAB/UTAD, Departamento de Engenharias, Quinta de Prados, 5001-801 Vila Real, Portugal (J.M.); (F.P.)
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8
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Vallet Y, Baldit A, Bertholdt C, Rahouadj R, Morel O, Laurent C. Characterization of the skin-to-bone mechanical interaction on porcine scalp: A combined experimental and computational approach. J Mech Behav Biomed Mater 2023; 147:106139. [PMID: 37757616 DOI: 10.1016/j.jmbbm.2023.106139] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 05/03/2023] [Accepted: 09/20/2023] [Indexed: 09/29/2023]
Abstract
Fasciae are soft tissues permitting a large but finite sliding between organs, but also between skin and its underlying elements. The contribution of fasciae has been seldomly reported in the literature, and is usually neglected or overly simplified within simulations. In the present contribution, we propose to use peeling tests in order to quantify the skin-to-bone interaction associated with a simple computational approach based on a geometrical modeling of the skin-to-bone interface. To this aim, a new experimental set up combined with a computational model to characterize the skin-to-bone interaction were proposed. The current work is devoted to the porcine scalp complex since it constitutes a common mechanical surrogate for the human scalp complex. The ad hoc computational approach and peeling set up were firstly evaluated on a validation material, before being used to characterize the skin-to-bone interaction within 6 porcine specimens harvested from the scalp. Our experimental setup allowed to measure the peeling response of porcine scalp, showing a three-regimes response including a plateau force. The computational approach satisfyingly reproduced the peeling response based uniquely on experimental-based parameters and on a discrete modeling of skin-to-bone interface. The presented methodology is a first attempt to propose a computationally efficient geometrically based model able to take into account the skin-to-bone interaction up to failure and corroborated by experimental data, and may be largely extended to the modeling of soft interactions between biological human tissues in the future.
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Affiliation(s)
- Y Vallet
- CNRS UMR 7239 LEM3 - Université de Lorraine, Nancy, France.
| | - A Baldit
- CNRS UMR 7239 LEM3 - Université de Lorraine, Nancy, France
| | - C Bertholdt
- Université de Lorraine, CHRU-NANCY, Pôle de la Femme, F-54000, Nancy, France; IADI, INSERM U1254, Rue du Morvan, 54500, Vandoeuvre-lès-nancy, France
| | - R Rahouadj
- CNRS UMR 7239 LEM3 - Université de Lorraine, Nancy, France
| | - O Morel
- Université de Lorraine, CHRU-NANCY, Pôle de la Femme, F-54000, Nancy, France; IADI, INSERM U1254, Rue du Morvan, 54500, Vandoeuvre-lès-nancy, France
| | - C Laurent
- CNRS UMR 7239 LEM3 - Université de Lorraine, Nancy, France
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Liu CT, Yu J, Lin MH, Chang KH, Lin CY, Cheng NC, Wu PI, Huang CW, Zhang PY, Hung MT, Hsiao YS. Biophysical Electrical and Mechanical Stimulations for Promoting Chondrogenesis of Stem Cells on PEDOT:PSS Conductive Polymer Scaffolds. Biomacromolecules 2023; 24:3858-3871. [PMID: 37523499 DOI: 10.1021/acs.biomac.3c00506] [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: 08/02/2023]
Abstract
The investigation of the effects of electrical and mechanical stimulations on chondrogenesis in tissue engineering scaffolds is essential for realizing successful cartilage repair and regeneration. The aim of articular cartilage tissue engineering is to enhance the function of damaged or diseased articular cartilage, which has limited regenerative capacity. Studies have shown that electrical stimulation (ES) promotes mesenchymal stem cell (MSC) chondrogenesis, while mechanical stimulation (MS) enhances the chondrogenic differentiation capacity of MSCs. Therefore, understanding the impact of these stimuli on chondrogenesis is crucial for researchers to develop more effective tissue engineering strategies for cartilage repair and regeneration. This study focuses on the preparation of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conductive polymer (CP) scaffolds using the freeze-drying method. The scaffolds were fabricated with varying concentrations (0, 1, 3, and 10 wt %) of (3-glycidyloxypropyl) trimethoxysilane (GOPS) as a crosslinker and an additive to tailor the scaffold properties. To gain a comprehensive understanding of the material characteristics and the phase aggregation phenomenon of PEDOT:PSS scaffolds, the researchers performed theoretical calculations of solubility parameters and surface energies of PSS, PSS-GOPS, and PEDOT polymers, as well as conducted material analyses. Additionally, the study investigated the potential of promoting chondrogenic differentiation of human adipose stem cells by applying external ES or MS on a PEDOT:PSS CP scaffold. Compared to the group without stimulation, the group that underwent stimulation exhibited significantly up-regulated expression levels of chondrogenic characteristic genes, such as SOX9 and COL2A1. Moreover, the immunofluorescence staining images exhibited a more vigorous fluorescence intensity of SOX9 and COL II proteins that was consistent with the trend of the gene expression results. In the MS experiment, the strain excitation exerted on the scaffold was simulated and transformed into stress. The simulated stress response showed that the peak gradually decreased with time and approached a constant value, with the negative value of stress representing the generation of tensile stress. This stress response quantification could aid researchers in determining specific MS conditions for various materials in tissue engineering, and the applied stress conditions could be further optimized. Overall, these findings are significant contributions to future research on cartilage repair and biophysical ES/MS in tissue engineering.
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Affiliation(s)
- Chun-Ting Liu
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
- Department of Chemical Engineering, College of Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Jiashing Yu
- Department of Chemical Engineering, College of Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Min-Hsuan Lin
- Department of Chemical Engineering, College of Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Kai-Hsiang Chang
- Department of Chemical Engineering, College of Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Che-Yu Lin
- Institute of Applied Mechanics, College of Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Nai-Chen Cheng
- Department of Surgery, National Taiwan University Hospital and College of Medicine, Taipei 10002, Taiwan
| | - Po-I Wu
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
| | - Chun-Wei Huang
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
| | - Pin-Yu Zhang
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
| | - Min-Tzu Hung
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
| | - Yu-Sheng Hsiao
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
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10
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Du R, Li L, Ji J, Fan Y. Receptor-Ligand Binding: Effect of Mechanical Factors. Int J Mol Sci 2023; 24:ijms24109062. [PMID: 37240408 DOI: 10.3390/ijms24109062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/20/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Gaining insight into the in situ receptor-ligand binding is pivotal for revealing the molecular mechanisms underlying the physiological and pathological processes and will contribute to drug discovery and biomedical application. An important issue involved is how the receptor-ligand binding responds to mechanical stimuli. This review aims to provide an overview of the current understanding of the effect of several representative mechanical factors, such as tension, shear stress, stretch, compression, and substrate stiffness on receptor-ligand binding, wherein the biomedical implications are focused. In addition, we highlight the importance of synergistic development of experimental and computational methods for fully understanding the in situ receptor-ligand binding, and further studies should focus on the coupling effects of these mechanical factors.
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Affiliation(s)
- Ruotian Du
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Long Li
- State Key Laboratory of Nonlinear Mechanics, Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jing Ji
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
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11
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O'Neill SJK, Huang Z, Ahmed MH, Boys AJ, Velasco-Bosom S, Li J, Owens RM, McCune JA, Malliaras GG, Scherman OA. Tissue-Mimetic Supramolecular Polymer Networks for Bioelectronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207634. [PMID: 36314408 DOI: 10.1002/adma.202207634] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 10/14/2022] [Indexed: 06/16/2023]
Abstract
Addressing the mechanical mismatch between biological tissue and traditional electronic materials remains a major challenge in bioelectronics. While rigidity of such materials limits biocompatibility, supramolecular polymer networks can harmoniously interface with biological tissues as they are soft, wet, and stretchable. Here, an electrically conductive supramolecular polymer network that simultaneously exhibits both electronic and ionic conductivity while maintaining tissue-mimetic mechanical properties, providing an ideal electronic interface with the human body, is introduced. Rational design of an ultrahigh affinity host-guest ternary complex led to binding affinities (>1013 M-2 ) of over an order of magnitude greater than previous reports. Embedding these complexes as dynamic cross-links, coupled with in situ synthesis of a conducting polymer, resulted in electrically conductive supramolecular polymer networks with tissue-mimetic Young's moduli (<5 kPa), high stretchability (>500%), rapid self-recovery and high water content (>84%). Achieving such properties enabled fabrication of intrinsically-stretchable stand-alone bioelectrodes, capable of accurately monitoring electromyography signals, free from any rigid materials.
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Affiliation(s)
- Stephen J K O'Neill
- Melville Laboratory for Polymer Synthesis, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Zehuan Huang
- Melville Laboratory for Polymer Synthesis, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Mohammed H Ahmed
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, UK
| | - Alexander J Boys
- Department of Chemical Engineering & Biotechnology, University of Cambridge, Cambridge, CB3 0FA, UK
| | - Santiago Velasco-Bosom
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, UK
| | - Jiaxuan Li
- Melville Laboratory for Polymer Synthesis, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Róisín M Owens
- Department of Chemical Engineering & Biotechnology, University of Cambridge, Cambridge, CB3 0FA, UK
| | - Jade A McCune
- Melville Laboratory for Polymer Synthesis, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - George G Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, UK
| | - Oren A Scherman
- Melville Laboratory for Polymer Synthesis, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
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12
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Durcan C, Hossain M, Chagnon G, Perić D, Karam G, Bsiesy L, Girard E. Experimental investigations of the human oesophagus: anisotropic properties of the embalmed mucosa-submucosa layer under large deformation. Biomech Model Mechanobiol 2022; 21:1685-1702. [PMID: 36030514 PMCID: PMC9420190 DOI: 10.1007/s10237-022-01613-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/24/2022] [Indexed: 11/23/2022]
Abstract
Mechanical characterisation of the layer-specific, viscoelastic properties of the human oesophagus is crucial in furthering the development of devices emerging in the field, such as robotic endoscopic biopsy devices, as well as in enhancing the realism, and therefore effectiveness, of surgical simulations. In this study, the viscoelastic and stress-softening behaviour of the passive human oesophagus was investigated through ex vivo cyclic mechanical tests. Due to restrictions placed on the laboratory as a result of COVID-19, only oesophagi from cadavers fixed in formalin were allowed for testing. Three oesophagi in total were separated into their two main layers and the mucosa-submucosa layer was investigated. A series of uniaxial tensile tests were conducted in the form of increasing stretch level cyclic tests at two different strain rates: 1% s[Formula: see text] and 10% s[Formula: see text]. Rectangular samples in both the longitudinal and circumferential directions were tested to observe any anisotropy. Histological analysis was also performed through a variety of staining methods. Overall, the longitudinal direction was found to be much stiffer than the circumferential direction. Stress-softening was observed in both directions, as well as permanent set and hysteresis. Strain rate-dependent behaviour was also apparent in the two directions, with an increase in strain rate resulting in an increase in stiffness. This strain rate dependency was more pronounced in the longitudinal direction than the circumferential direction. Finally, the results were discussed in regard to the histological content of the layer, and the behaviour was modelled and validated using a visco-hyperelastic matrix-fibre model.
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Affiliation(s)
- Ciara Durcan
- Zienkiewicz Centre for Computational Engineering, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN UK
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Mokarram Hossain
- Zienkiewicz Centre for Computational Engineering, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN UK
| | - Grégory Chagnon
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Djordje Perić
- Zienkiewicz Centre for Computational Engineering, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN UK
| | - Georges Karam
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Lara Bsiesy
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Edouard Girard
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
- Laboratoire d’Anatomie des Alpes Françaises, Université Grenoble Alpes, Grenoble, France
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13
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Reddy GA, Katira P. Differences in cell death and division rules can alter tissue rigidity and fluidization. SOFT MATTER 2022; 18:3713-3724. [PMID: 35502875 DOI: 10.1039/d2sm00174h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Tissue mechanical properties such as rigidity and fluidity, and changes in these properties driven by jamming-unjamming transitions (UJT), have come under recent highlight as mechanical markers of health and disease in various biological processes including cancer. However, most analyses of these mechanical properties and UJT have sidestepped the effect of cellular death and division in these systems. Cellular apoptosis (programmed cell death) and mitosis (cell division) can drive significant changes in tissue properties. The balance between the two is crucial in maintaining tissue function, and an imbalance between the two is seen in situations such as cancer progression, wound healing and necrosis. In this work we investigate the impact of cell death and division on tissue mechanical properties, by incorporating specific mechanosensitive triggers of cell death and division based on the size and geometry of the cell within in silico models of tissue dynamics. Specifically, we look at cell migration, tissue response to external stress, tissue extrusion propensity and self-organization of different cell types within the tissue, as a function of cell death and division and the rules that trigger these events. We find that not only do cell death and division events significantly alter tissue mechanics when compared to systems without these events, but that the choice of triggers driving these cell death and division events also alters the predicted tissue mechanics and overall system behavior.
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Affiliation(s)
- Gudur Ashrith Reddy
- Mechanical Engineering Department, San Diego State University, San Diego, CA, USA.
- Department of Bioengineering, University of California - San Diego, San Diego, CA, USA
| | - Parag Katira
- Mechanical Engineering Department, San Diego State University, San Diego, CA, USA.
- Computational Science Research Center, San Diego State University, San Diego, CA, USA
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14
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Bose S, Li S, Mele E, Silberschmidt VV. Exploring the Mechanical Properties and Performance of Type-I Collagen at Various Length Scales: A Progress Report. MATERIALS 2022; 15:ma15082753. [PMID: 35454443 PMCID: PMC9025246 DOI: 10.3390/ma15082753] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/04/2022] [Accepted: 04/06/2022] [Indexed: 12/30/2022]
Abstract
Collagen is the basic protein of animal tissues and has a complex hierarchical structure. It plays a crucial role in maintaining the mechanical and structural stability of biological tissues. Over the years, it has become a material of interest in the biomedical industries thanks to its excellent biocompatibility and biodegradability and low antigenicity. Despite its significance, the mechanical properties and performance of pure collagen have been never reviewed. In this work, the emphasis is on the mechanics of collagen at different hierarchical levels and its long-term mechanical performance. In addition, the effect of hydration, important for various applications, was considered throughout the study because of its dramatic influence on the mechanics of collagen. Furthermore, the discrepancies in reports of the mechanical properties of collagenous tissues (basically composed of 20-30% collagen fibres) and those of pure collagen are discussed.
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Affiliation(s)
- Shirsha Bose
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, Leicestershire, UK; (S.B.); (S.L.)
| | - Simin Li
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, Leicestershire, UK; (S.B.); (S.L.)
| | - Elisa Mele
- Department of Materials, Loughborough University, Loughborough LE11 3TU, Leicestershire, UK
- Correspondence: (E.M.); (V.V.S.)
| | - Vadim V. Silberschmidt
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, Leicestershire, UK; (S.B.); (S.L.)
- Laboratory of Mechanics of Biocompatible Materials and Devices, Perm National Research Polytechnic University, 614990 Perm, Russia
- Correspondence: (E.M.); (V.V.S.)
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15
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Orozco GA, Tanska P, Gustafsson A, Korhonen RK, Isaksson H. Crack propagation in articular cartilage under cyclic loading using cohesive finite element modeling. J Mech Behav Biomed Mater 2022; 131:105227. [DOI: 10.1016/j.jmbbm.2022.105227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/01/2022] [Accepted: 04/02/2022] [Indexed: 11/28/2022]
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16
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Dwivedi KK, Lakhani P, Kumar S, Kumar N. Effect of collagen fibre orientation on the Poisson's ratio and stress relaxation of skin: an ex vivo and in vivo study. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211301. [PMID: 35345435 PMCID: PMC8941416 DOI: 10.1098/rsos.211301] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
During surgical treatment skin undergoes extensive deformation, hence it must be able to withstand large mechanical stresses without damage. Therefore, understanding the mechanical properties of skin becomes important. A detailed investigation on the relationship between the three-dimensional deformation response of skin and its microstructure is conducted in the current study. This study also discloses the underlying science of skin viscoelasticity. Deformation response of skin is captured using digital image correlation, whereas micro-CT, scanning electron microscopy and atomic force microscopy are used for microstructure analysis. Skin shows a large lateral contraction and expansion (auxeticity) when stretched parallel and perpendicular to the skin tension lines, respectively. Large lateral contraction is a result of fluid exudation from the tissue, while large rotation of the stiff collagen fibres in the loading direction explains the skin auxeticity. During stress relaxation, lateral contraction and fluid effluxion from skin reveal that tissue volume loss is the intrinsic science of skin viscoelasticity. Furthermore, the results obtained from in vivo study on human skin show the relevance of the ex vivo study to physiological conditions and stretching of the skin during its treatments.
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Affiliation(s)
- Krashn Kumar Dwivedi
- Department of Biomedical Engineering, Indian Institute of Technology, Ropar, India
| | - Piyush Lakhani
- Department of Mechanical Engineering, Indian Institute of Technology, Ropar, 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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17
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Dwivedi KK, Lakhani P, Kumar S, Kumar N. A hyperelastic model to capture the mechanical behaviour and histological aspects of the soft tissues. J Mech Behav Biomed Mater 2021; 126:105013. [PMID: 34920323 DOI: 10.1016/j.jmbbm.2021.105013] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/10/2021] [Accepted: 11/27/2021] [Indexed: 11/19/2022]
Abstract
It is well established that the soft connective tissues show a nonlinear elastic response that comes from their microstructural arrangement. Tissues' microstructure alters with various physiological conditions and may affect their mechanical responses. Therefore, the accurate prediction of tissue's mechanical response is crucial for clinical diagnosis and treatments. Thus, a physically motivated and mathematically simplified model is required for the accurate prediction of tissues' mechanical and structural responses. This study explored the 'Exp-Ln' hyperelastic model (Khajehsaeid et al., 2013) to capture soft tissues' mechanical and histological behaviour. In this work, uniaxial tensile test data for the belly and back pig skin were extracted from the experiments performed in our laboratory, whereas uniaxial test data for other soft tissues (human skin, tendon, ligament, and aorta) were extracted from the literature. The 'Exp-Ln; and other hyperelastic models (e.g. Money Rivlin, Ogden, Yeoh, and Gent models) were fitted with these experimental data, and obtained results were compared between the models. These results show that the 'Exp-Ln' model could capture the mechanical behaviour of soft tissues more accurately than other hyperelastic models. This model was also found numerically stable for all modes and ranges of deformation. This study also investigated the link between 'Exp-Ln' material parameters and tissue's histological parameters. The histological parameters such as collagen content, fibre free length, crosslink density, and collagen arrangement were measured using staining and ATR-FTIR techniques. The material parameters were found statistically correlated with the histological parameters. Further, 'Exp-Ln' model was implemented in ABAQUS through the VUMAT subroutine, where the mechanical behaviour of various soft tissues was simulated for different modes of deformation. The finite element analysis results obtained using the 'Exp-Ln' model agreed with the experiments and were more accurate than other hyperelastic models. Overall, these results demonstrate the capability of 'Exp-Ln' model to predict the mechanical and structural responses of the soft tissues.
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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
| | - 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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18
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Irwin T, Speirs A, Merrett C. The effect of skin tension, needle diameter and insertion velocity on the fracture properties of porcine tissue. J Mech Behav Biomed Mater 2021; 123:104660. [PMID: 34329813 DOI: 10.1016/j.jmbbm.2021.104660] [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: 06/26/2020] [Revised: 06/06/2021] [Accepted: 06/24/2021] [Indexed: 11/19/2022]
Abstract
Using metal needles to penetrate skin tissue is common in medical treatments for the delivery of medication or minimally invasive surgery. In most applications the fracture properties of skin tissue is not important as the human surgeon has full control over the needle. Given that robotically controlled surgeries and self applied medical devices have become increasingly popular, a better understanding of the fracture properties and how to mathematically model the fracture process is needed. Experiments measuring the force required to fracture porcine skin tissue were done while varying the applied skin tension, needle insertion speed and needle diameter. The applied skin tension was found to have the greatest influence on the fracture properties, while the insertion speed was found to have a negligible impact. The variance in experimental results was not well explained by the three independent variables alone, suggesting that additional parameters influence the fracture process.
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Affiliation(s)
- T Irwin
- Carleton University, 1125 Colonel By Drive, Ottawa, Canada.
| | - A Speirs
- Carleton University, 1125 Colonel By Drive, Ottawa, Canada.
| | - C Merrett
- Carleton University, 1125 Colonel By Drive, Ottawa, Canada.
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19
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Skin under Strain: From Epithelial Model Tissues to Adult Epithelia. Cells 2021; 10:cells10071834. [PMID: 34360001 PMCID: PMC8304960 DOI: 10.3390/cells10071834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 01/14/2023] Open
Abstract
Formation of a barrier capable of protecting tissue from external damage, chemical factors, and pathogens is one of the main functions of the epidermis. Furthermore, upon development and during aging, mechanoprotective epidermal functions change dramatically. However, comparative studies between embryonic and adult skin in comparison to skin equivalents are still scarce which is especially due to the lack of appropriate measurement systems with sufficient accuracy and long-term tissue compatibility. Our studies fill this gap by developing a combined bioreactor and tensile testing machine for biomechanical analysis of living epithelia. Based on this tissue stretcher, our data clearly show that viscoelastic and plastic deformation behavior of embryonic and adult skin differ significantly. Tissue responses to static strain compared to cyclic strain also show a clear dependence on differentiation stage. Multilayered unkeratinized epidermis equivalents, on the other hand, respond very similar to mechanical stretch as adult tissue. This mechanical similarity is even more evident after a single cycle of mechanical preconditioning. Our studies therefore suggest that skin equivalents are well suited model systems to analyze cellular interactions of epidermal cells in natural tissues.
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20
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Witte M, Rübhausen M, Jaspers S, Wenck H, Fischer F. A method to analyze the influence of mechanical strain on dermal collagen morphologies. Sci Rep 2021; 11:7565. [PMID: 33828115 PMCID: PMC8027212 DOI: 10.1038/s41598-021-86907-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 02/17/2021] [Indexed: 11/09/2022] Open
Abstract
Collagen fibers and their orientation play a major role in the mechanical behavior of soft biological tissue such as skin. Here, we present a proof-of-principle study correlating mechanical properties with collagen fiber network morphologies. A dedicated multiphoton stretching device allows for mechanical deformations in combination with a simultaneous analysis of its collagen fiber network by second harmonic generation imaging (SHG). The recently introduced Fiber Image Network Evaluation (FINE) algorithm is used to obtain detailed information about the morphology with regard to fiber families in collagen network images. To demonstrate the potential of our method, we investigate an isotropic and an anisotropic ex-vivo dorsal pig skin sample under quasi-static cyclic stretching and relaxation sequences. Families of collagen fibers are found to form a partially aligned collagen network under strain. We find that the relative force uptake is accomplished in two steps. Firstly, fibers align within their fiber families and, secondly, fiber families orient in the direction of force. The maximum alignment of the collagen fiber network is found to be determined by the largest strain. Isotropic and anisotropic samples reveal a different micro structural behavior under repeated deformation leading to a similar force uptake after two stretching cycles. Our method correlates mechanical properties with morphologies in collagen fiber networks.
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Affiliation(s)
- Maximilian Witte
- Center for Free-Electron Laser Science (CFEL), University of Hamburg, Hamburg, 22607, Germany.,Beiersdorf AG, Hamburg, 20245, Germany
| | - Michael Rübhausen
- Center for Free-Electron Laser Science (CFEL), University of Hamburg, Hamburg, 22607, Germany
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21
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Al-Majhali SH, Khairuddin NH, Abdul Razak IS, Radzi Z, Rahman MT, Sapalo JT, Mayaki AM, Czernuszka JT. Biomechanical Effects of Unidirectional Expansion Using Anisotropic Expanders in Horse Skin Tissue. J Equine Vet Sci 2021; 99:103399. [PMID: 33781409 DOI: 10.1016/j.jevs.2021.103399] [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: 08/12/2020] [Revised: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 11/27/2022]
Abstract
The use of a self-inflating tissue expander is a technique to stretch cutaneous tissues for potential use in reconstructive skin surgeries. This study investigates the mechanical properties of horse skin stretched by the subcutaneous implantation of anisotropic tissue expanders at the forehead, right shoulder, and dorsomedial part of the cannon region of the right forelimb in six (n = 6) horses. After 14 days of skin expansion, expanded and normal (control) skin samples were harvested and their mechanical properties of elastic modulus (EM), maximum force (MF), maximum stress (MSs) and maximum strain (MSr) were evaluated using uniaxial tension test. The expanded skin from shoulder area has higher EM, MSs, MSr and MF than the normal skin when compared to the forehead and lower forelimb. Statistically, there was a significant (P= .02) mean difference for MSs between the expanded shoulder and lower forelimb skin, but the pairwise comparison of EM, MSr and MF showed no significant difference between the locations. The overall effect of locations on EM and MSs was statistically significant (P < .05), however, there was no overall effect of horse factor, treatment factor (normal and expanded skin) and location interaction on the EM, MSS, MF and MSr. In conclusion, the expanded skin from the frontal head and the distal limb are less elastic (stiffer) compared to that of the expanded skin of the shoulder, thus anatomical location of the skin has some degree of effect on EM and MSs.
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Affiliation(s)
| | - Nurul Hayah Khairuddin
- Department of Farm and Exotic Animal Medicine and Surgery, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Intan Shameha Abdul Razak
- Department of Veterinary Preclinical Science, Faculty of Veterinary Medicine, Universiti Putra Malaysia
| | - Zamri Radzi
- Faculty of Dentistry, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | | | | | - Abubakar Musa Mayaki
- Department of Veterinary Medicine, Usmanu Danfodiyo University, PMB 2346, Sokoto, Nigeria
| | - Jan T Czernuszka
- Department of Materials, University of Oxford, Parks Road, OX1 3PH, United Kingdom
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Dry vs. wet: Properties and performance of collagen films. Part II. Cyclic and time-dependent behaviours. J Mech Behav Biomed Mater 2020; 112:104040. [DOI: 10.1016/j.jmbbm.2020.104040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/08/2020] [Accepted: 08/12/2020] [Indexed: 12/21/2022]
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Liu T, Shen M, Li H, Zhang Y, Mu B, Zhao X, Wang Y. Changes and quantitative characterization of hyper-viscoelastic biomechanical properties for young corneal stroma after standard corneal cross-linking treatment with different ultraviolet-A energies. Acta Biomater 2020; 113:438-451. [PMID: 32525050 DOI: 10.1016/j.actbio.2020.06.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/30/2020] [Accepted: 06/02/2020] [Indexed: 12/27/2022]
Abstract
Corneal collagen cross-linking (CXL) treatment can restore vision in patients suffering from keratoconus and corneal injury, by improving the mechanical properties of the cornea. The correlation between ultraviolet-A (UVA) irradiant energies of standard CXL (SCXL) and corneal visco-hyperelastic mechanical behavior remains unknown. In this study, SCXL with four different UVA irradiant energy doses (0-5.4 J/cm2) were administered as part of quantitative treatments of corneal stromal lenticules extracted from young myopic patients via small incision lenticule extraction (SMILE) corneal refractive surgery. Double-strip samples with symmetric geometries were cut simultaneously for SCXL treatment and non-treated control. First, 40 pairs of strips were loaded to failure to assess the mechanical parameters of the material. Then, another 40 pairs were tested using a special uniaxial tensile test including quasi-static loading-unloading, instantaneous loading, and stress relaxation, to determine the visco-hyperelastic mechanical behavior. Upon combining the collagen fibril crimping constitutive model with the quasi-linear viscoelastic model, it was observed that with increasing UVA energy dose, the corneal strength and hyperelastic stiffness were significantly enhanced, while the maximum stretch and viscosity of the cornea were significantly reduced. Considering the quantitative analysis of SCXL and the rehabilitation prediction of keratoconus treatment, the results clarify the biomechanical behavior of human corneal stroma in SCXL clinical surgery. STATEMENT OF SIGNIFICANCE: This study quantitatively analyzes the improvement in the biomechanical properties of young central corneal stroma, due to SCXL treatment with different energies. Furthermore, the correlation between the hyper-viscoelastic mechanical parameters and UVA irradiant energy doses of SCXL are clarified. The contribution of this study fills the knowledge gap of the CXL on corneal biomechanics. It can not only clarify this mechanism better but also assist with guiding SCXL surgery for individualized patient corneas.
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Affiliation(s)
- Taiwei Liu
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350 China; Department of Engineering Mechanics, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Min Shen
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350 China.
| | - Hongxun Li
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin 300020 China; Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070 China
| | - Yan Zhang
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin 300020 China; Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070 China
| | - Bokun Mu
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin 300020 China; Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070 China
| | - Xinheng Zhao
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin 300020 China; Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070 China
| | - Yan Wang
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin 300020 China; Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070 China
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Dwivedi KK, Lakhani P, Kumar S, Kumar N. The Effect of Strain Rate on the Stress Relaxation of the Pig Dermis: A Hyper-Viscoelastic Approach. J Biomech Eng 2020; 142:091006. [PMID: 32005989 DOI: 10.1115/1.4046205] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Indexed: 01/01/2023]
Abstract
The understanding of strain rate-dependent mechanical properties of the skin is important for accurate prediction of its biomechanics under different loading conditions. This study investigated the effect of strain rate, i.e., 0.025/s (low), 0.5/s (medium), and 1.25/s (high), ranging in the physiological loading rate of connective tissue, on the stress-relaxation response of the porcine dermis. Results show that in the initial phase of the relaxation, the value of stress relaxation (extent of relaxation) was found higher for high strain rate. However, the equilibrium stress was found strain rate independent. A Mooney-Rivlin-based five-term quasi-linear viscoelastic (QLV) model was proposed to determine the effect of strain rate on the stress-relaxation behavior of the porcine dermis. The value of relaxation modulus G1 and G2 were found higher for the high strain rate, whereas the reverse trend was observed for G3, G4, and G5. Moreover, the value of time constants τ1,τ2,τ3τ4, and τ5 were found higher for low strain rate. Statistical analysis shows no significant difference in the values of G5, τ4, and τ5 among the three strain rates. The proposed model was found capable to fit the stress-relaxation response of skin with great accuracy, e.g., root-mean-squared-error (RMSE) value equal to 0.015 ± 0.00012 MPa. Moreover, this hyper-viscoelastic model can be utilized: to quantify the effects of age and diseases on the skin; to simulate the stresses on sutures during large wound closure and impact loading.
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Affiliation(s)
- Krashn K Dwivedi
- Centre for Biomedical Engineering, Indian Institute of Technology Ropar, Punjab 140001, India
| | - Piyush Lakhani
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Punjab 140001, India
| | - Sachin Kumar
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Punjab 140001, India
| | - Navin Kumar
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Punjab 140001, India
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25
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Dwivedi KK, Lakhani P, Kumar S, Kumar N. Frequency dependent inelastic response of collagen architecture of pig dermis under cyclic tensile loading: An experimental study. J Mech Behav Biomed Mater 2020; 112:104030. [PMID: 32858398 DOI: 10.1016/j.jmbbm.2020.104030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/06/2020] [Accepted: 08/07/2020] [Indexed: 01/20/2023]
Abstract
The evaluation of collagen architecture of the dermis in response to mechanical stimulation is important as it affects the macroscopic mechanical properties of the dermis. A detailed understanding of the processes involved in the alteration of the collagen structure is required to correlate the mechanical stimulation with tissue remodeling. This study investigated the effect of cyclic frequencies i.e. low (0.1 Hz), medium (2.0 Hz), and high (5.0 Hz) (physiological range) in the alteration of pig dermis collagen structure and its correlation with the macroscopic mechanical response of the dermis. The assessment of the collagen structure of virgin and mechanical tested specimens at tropocollagen, collagen fibril, and fiber level was performed using Fourier-transform infrared-attenuated total reflection (FTIR-ATR), atomic force microscopy (AFM), and scanning electron microscopy (SEM) respectively. After 103 cycles, a significantly higher alteration in collagen structure with discrete plastic-type damage was found for low frequency. This frequency dependent alteration of the collagen structure was found in correlation with the dermis macroscopic response. The value of inelastic strain, stress softening, damage parameter (reduction in elastic modulus), and reduction in energy dissipation were observed significantly large for slow frequency. A power-law based empirical relations, as a function of frequency and number of cycles, were proposed to predict the value of inelastic strain and damage parameter. This study also suggests that hierarchical structural response against the mechanical stimulation is time-dependent rather than cycle-dependent, may affect the tissue remodeling.
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Affiliation(s)
| | | | - Sachin Kumar
- Department of Mechanical Engineering, IIT, Ropar, India.
| | - Navin Kumar
- Center for Biomedical Engineering Department, IIT, Ropar, India; Department of Mechanical Engineering, IIT, Ropar, India.
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26
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Cochereau T, Bailly L, Orgéas L, Henrich Bernardoni N, Robert Y, Terrien M. Mechanics of human vocal folds layers during finite strains in tension, compression and shear. J Biomech 2020; 110:109956. [PMID: 32827774 DOI: 10.1016/j.jbiomech.2020.109956] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 12/17/2022]
Abstract
During phonation, human vocal fold tissues are subjected to combined tension, compression and shear loading modes from small to large finite strains. Their mechanical behaviour is however still not well understood. Herein, we complete the existing mechanical database of these soft tissues, by characterising, for the first time, the cyclic and finite strains behaviour of the lamina propria and vocalis layers under these loading modes. To minimise the inter or intra-individual variability, particular attention was paid to subject each tissue sample successively to the three loadings. A non-linear mechanical behaviour is observed for all loading modes: a J-shape strain stiffening in longitudinal tension and transverse compression, albeit far less pronounced in shear, stress accommodation and stress hysteresis whatever the loading mode. In addition, recorded stress levels during longitudinal tension are much higher for the lamina propria than for the vocalis. Conversely, the responses of the lamina propria and the vocalis in transverse compression as well as transverse and longitudinal shears are of the same orders of magnitude. We also highlight the strain rate sensitivity of the tissues, as well as their anisotropic properties.
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Affiliation(s)
- Thibaud Cochereau
- Univ. Grenoble Alpes, CNRS, Grenoble INP, 3SR, 38000 Grenoble, France; Univ. Grenoble Alpes, CNRS, Grenoble INP, GIPSA-lab, 38000 Grenoble, France
| | - Lucie Bailly
- Univ. Grenoble Alpes, CNRS, Grenoble INP, 3SR, 38000 Grenoble, France.
| | - Laurent Orgéas
- Univ. Grenoble Alpes, CNRS, Grenoble INP, 3SR, 38000 Grenoble, France
| | | | - Yohann Robert
- Univ. Grenoble Alpes, CHU Grenoble Alpes, LADAF, 38000 Grenoble, France
| | - Maxime Terrien
- Univ. Grenoble Alpes, CNRS, Grenoble INP, LGP2, 38000 Grenoble, France
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27
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Paritala PK, Yarlagadda PKDV, Kansky R, Wang J, Mendieta JB, Gu Y, McGahan T, Lloyd T, Li Z. Stress-Relaxation and Cyclic Behavior of Human Carotid Plaque Tissue. Front Bioeng Biotechnol 2020; 8:60. [PMID: 32117939 PMCID: PMC7026010 DOI: 10.3389/fbioe.2020.00060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/23/2020] [Indexed: 12/12/2022] Open
Abstract
Atherosclerotic plaque rupture is a catastrophic event that contributes to mortality and long-term disability. A better understanding of the plaque mechanical behavior is essential for the identification of vulnerable plaques pre-rupture. Plaque is subjected to a natural dynamic mechanical environment under hemodynamic loading. Therefore, it is important to understand the mechanical response of plaque tissue under cyclic loading conditions. Moreover, experimental data of such mechanical properties are fundamental for more clinically relevant biomechanical modeling and numerical simulations for risk stratification. This study aims to experimentally and numerically characterize the stress-relaxation and cyclic mechanical behavior of carotid plaque tissue. Instron microtester equipped with a custom-developed setup was used for the experiments. Carotid plaque samples excised at endarterectomy were subjected to uniaxial tensile, stress-relaxation, and cyclic loading protocols. Thirty percent of the underlying load level obtained from the uniaxial tensile test results was used to determine the change in mechanical properties of the tissue over time under a controlled testing environment (Control tests). The stress-relaxation test data was used to calibrate the hyperelastic (neo-Hookean, Ogden, Yeoh) and linear viscoelastic (Prony series) material parameters. The normalized relaxation force increased initially and slowly stabilized toward the end of relaxation phase, highlighting the viscoelastic behavior. During the cyclic tests, there was a decrease in the peak force as a function of the cycle number indicating mechanical distension due to repeated loading that varied with different frequencies. The material also accumulated residual deformation, which increased with the cycle number. This trend showed softening behavior of the samples. The results of this preliminary study provide an enhanced understanding of in vivo stress-relaxation and cyclic behavior of the human atherosclerotic plaque tissue.
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Affiliation(s)
- Phani Kumari Paritala
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Prasad K D V Yarlagadda
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Rhys Kansky
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Jiaqiu Wang
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Jessica Benitez Mendieta
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - YuanTong Gu
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Tim McGahan
- Department of Vascular Surgery, Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Thomas Lloyd
- Department of Radiology, Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Zhiyong Li
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
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Ibrahim MM, Green JL, Everitt J, Ruppert D, Glisson R, Leopardi F, Risoli T, Kuchibhatla M, Reynolds R, Levinson H. Soft Tissue Anchoring Performance, Biomechanical Properties, and Tissue Reaction of a New Hernia Mesh Engineered to Address Hernia Occurrence and Recurrence. J Med Device 2019; 13:0450021-450029. [PMID: 32280408 PMCID: PMC7104760 DOI: 10.1115/1.4043740] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 04/24/2019] [Indexed: 01/22/2023] Open
Abstract
One opportunity to reduce hernia occurrence and recurrence rates (currently estimated to be 30% at 10 years postoperatively) is by enhancing the ability of hernia meshes to anchor into tissue to prevent mesh migration, mesh contraction, and mesh tearing away from tissue. To address this, we developed a novel moderate-weight, macroporous, polypropylene mesh (termed the T-line mesh) with mesh extensions to optimize anchoring. We examined the physical properties, biomechanical performance, and biocompatibility of this novel mesh versus a predicate mesh anchored with #0-suture. The physical properties of the T-line mesh and predicate mesh were measured using American Society for Testing and Materials (ASTM) standards. Meshes were implanted into a swine hernia model and harvested after one day to determine anchoring strength of the meshes in the perioperative period. A separate group was implanted into a swine hernia model and harvested at 30 days and 90 days for semiquantitative histological analysis of biocompatibility. T-line mesh physical properties were similar to commonly used moderate-weight meshes in thickness and areal density. The T-line mesh outperformed the predicate mesh in all mechanical testing (P < 0.05). In the perioperative period, the T-line mesh was ∼275% stronger (P < 0.001) than the standard of care. Histological analysis of biocompatibility demonstrated no significant difference between the T-line mesh and predicate mesh (P > 0.05). The T-line mesh is a novel hernia mesh that outperforms a predicate mesh in mechanical and biomechanical performance testing while exhibiting similar biocompatibility. The T-line mesh has the potential to reduce hernia occurrence and recurrence caused by mechanical failure.
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Affiliation(s)
- Mohamad M. Ibrahim
- Division of Plastic, Maxillofacial, and Oral Surgery, Department of
Surgery, Duke University Medical Center, DUMC
3181, Durham, NC 27710
| | - Jason L. Green
- Duke University School of Medicine,
487 Medical Science Research Building 1, 203 Research Drive, Durham,
NC 27710
| | - Jeffrey Everitt
- Department of Pathology, Duke University Medical
Center, Durham, NC 27710
| | - David Ruppert
- Division of Plastic and Reconstructive Surgery, Department of Surgery,
Duke University Medical Center, Durham, NC
27710
| | - Richard Glisson
- Department of Orthopaedic Surgery, Duke University Medical
Center, Durham, NC 27710
| | - Frank Leopardi
- Department of Surgery, Duke University Medical
Center, Durham, NC 27710
| | - Thomas Risoli
- Department of Biostatistics and Bioinformatics, Duke
University Medical Center, Durham, NC
27710
| | - Maragatha Kuchibhatla
- Department of Biostatistics and Bioinformatics, Duke
University Medical Center, Durham, NC
27710
| | - Randall Reynolds
- Division of Lab Animal Resources (DLAR), Duke University
School of Medicine, Durham, NC 27710
| | - Howard Levinson
- Division of Plastic and Reconstructive Surgery, Department of Surgery,
Duke University Medical Center, Durham, NC
27710
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29
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Viscoelasticity in natural tissues and engineered scaffolds for tissue reconstruction. Acta Biomater 2019; 97:74-92. [PMID: 31400521 DOI: 10.1016/j.actbio.2019.08.013] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/23/2019] [Accepted: 08/06/2019] [Indexed: 02/05/2023]
Abstract
Viscoelasticity of living tissues plays a critical role in tissue homeostasis and regeneration, and its implication in disease development and progression is being recognized recently. In this review, we first explored the state of knowledge regarding the potential application of tissue viscoelasticity in disease diagnosis. In order to better characterize viscoelasticity with local resolution and non-invasiveness, emerging characterization methods have been developed with the potential to be supplemented to existing facilities. To understand cellular responses to matrix viscoelastic behaviors in vitro, hydrogels made of natural polymers have been developed and the relationships between their molecular structure and viscoelastic behaviors, are elucidated. Moreover, how cells perceive the viscoelastic microenvironment and cellular responses including cell attachment, spreading, proliferation, differentiation and matrix production, have been discussed. Finally, some future perspective on an integrated mechanobiological comprehension of the viscoelastic behaviors involved in tissue homeostasis, cellular responses and biomaterial design are highlighted. STATEMENT OF SIGNIFICANCE: Tissue- or organ-scale viscoelastic behavior is critical for homeostasis, and the molecular basis and cellular responses of viscoelastic materials at micro- or nano-scale are being recognized recently. We summarized the potential applications of viscoelasticity in disease diagnosis enabled by emerging non-invasive characterization technologies, and discussed the underlying mechanism of viscoelasticity of hydrogels and current understandings of cell regulatory functions of them. With a growing understanding of the molecular basis of hydrogel viscoelasticity and recognition of its regulatory functions on cell behaviors, it is important to bring the clinical insights on how these characterization technologies and engineered materials may contribute to disease diagnosis and treatment. This review explains the basics in characterizing viscoelasticity with our hope to bridge the gap between basic research and clinical applications.
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30
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Blattner CM, Perry B, Young J, Lear W. The use of a suture retention device to enhance tissue expansion and healing in the repair of scalp and lower leg wounds. JAAD Case Rep 2018; 4:655-661. [PMID: 30109254 PMCID: PMC6089068 DOI: 10.1016/j.jdcr.2018.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
| | - Benjamin Perry
- Department of Dermatology, Silver Falls Dermatology, Salem, Oregon.,Department of Dermatologic Surgery, Silver Falls Dermatology, Salem, Oregon
| | - John Young
- Department of Dermatology, Silver Falls Dermatology, Salem, Oregon
| | - William Lear
- Department of Dermatology, Silver Falls Dermatology, Salem, Oregon.,Department of Dermatologic Surgery, Silver Falls Dermatology, Salem, Oregon
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