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Abstract
When touched, a glass plate excited with ultrasonic transverse waves feels notably more slippery than it does at rest. To study this phenomenon, we use frustrated total internal reflection to image the asperities of the skin that are in intimate contact with a glass plate. We observed that the load at the interface is shared between the elastic compression of the asperities of the skin and a squeeze film of air. Stroboscopic investigation reveals that the time evolution of the interfacial gap is partially out of phase with the plate vibration. Taken together, these results suggest that the skin bounces against the vibrating plate but that the bounces are cushioned by a squeeze film of air that does not have time to escape the interfacial separation. This behavior results in dynamic levitation, in which the average number of asperities in intimate contact is reduced, thereby reducing friction. This improved understanding of the physics of friction reduction provides key guidelines for designing interfaces that can dynamically modulate friction with soft materials and biological tissues, such as human fingertips.
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252
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Yuan JH, Shi Y, Pharr M, Feng X, Rogers JA, Huang Y. A Mechanics Model for Sensors Imperfectly Bonded to the Skin for Determination of the Young's Moduli of Epidermis and Dermis. JOURNAL OF APPLIED MECHANICS 2016; 83:0845011-845013. [PMID: 27330219 PMCID: PMC4893765 DOI: 10.1115/1.4033650] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/12/2016] [Indexed: 05/04/2023]
Abstract
A mechanics model is developed for the encapsulated piezoelectric thin-film actuators/sensors system imperfectly bonded to the human skin to simultaneously determine the Young's moduli of the epidermis and dermis as well as the thickness of epidermis.
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Affiliation(s)
- J H Yuan
- Center for Mechanics and Materials, Tsinghua University, Beijing 100084, China
| | - Y Shi
- Center for Mechanics and Materials, Tsinghua University, Beijing 100084, China
| | - M Pharr
- Frederick Seitz Materials Research Laboratory, Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - X Feng
- Center for Mechanics and Materials, Tsinghua University, Beijing 100084, China
| | - John A Rogers
- Frederick Seitz Materials Research Laboratory, Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Yonggang Huang
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208
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253
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Osborn L, Nguyen H, Betthauser J, Kaliki R, Thakor N. Biologically inspired multi-layered synthetic skin for tactile feedback in prosthetic limbs. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2016:4622-4625. [PMID: 28269305 PMCID: PMC8092020 DOI: 10.1109/embc.2016.7591757] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The human body offers a template for many state-of-the-art prosthetic devices and sensors. In this work, we present a novel, sensorized synthetic skin that mimics the natural multi-layered nature of mechanoreceptors found in healthy glabrous skin to provide tactile information. The multi-layered sensor is made up of flexible piezoresistive textiles that act as force sensitive resistors (FSRs) to convey tactile information, which are embedded within a silicone rubber to resemble the compliant nature of human skin. The top layer of the synthetic skin is capable of detecting small loads less than 5 N whereas the bottom sensing layer responds reliably to loads over 7 N. Finite element analysis (FEA) of a simplified human fingertip and the synthetic skin was performed. Results suggest similarities in behavior during loading. A natural tactile event is simulated by loading the synthetic skin on a prosthetic limb. Results show the sensors' ability to detect applied loads as well as the ability to simulate neural spiking activity based on the derivative and temporal differences of the sensor response. During the tactile loading, the top sensing layer responded 0.24 s faster than the bottom sensing layer. A synthetic biologically-inspired skin such as this will be useful for enhancing the functionality of prosthetic limbs through tactile feedback.
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254
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Jeong MK, Hwang C, Nam H, Cho YS, Kang BY, Cho EC. Effect of the gel elasticity of model skin matrices on the distance/depth-dependent transmission of vibration energy supplied from a cosmetic vibrator. Int J Cosmet Sci 2016; 39:42-48. [PMID: 27264842 DOI: 10.1111/ics.12346] [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: 03/21/2016] [Accepted: 06/02/2016] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The purpose of this study was to determine how the energies supplied from a cosmetic vibrator are deeply or far transferred into organs and tissues, and how these depths or distances are influenced by tissue elasticity. METHODS External vibration energy was applied to model skin surfaces through a facial cleansing vibrator, and we measured a distance- and depth-dependent energy that was transferred to model skin matrices. As model skin matrices, we synthesized hard and soft poly(dimethylsiloxane) (PDMS) gels, as well as hydrogels with a modulus of 2.63 MPa, 0.33 MPa and 21 kPa, respectively, mostly representing those of skin and other organs. The transfer of vibration energy was measured either by increasing the separation distances or by increasing the depth from the vibrator. RESULTS The energies were transmitted deeper into the hard PDMS than into the soft PDMS and hydrogel matrices. This finding implies that the vibration forces influence a larger area of the gel matrices when the gels are more elastic (or rigid). There were no appreciable differences between the soft PDMS and hydrogel matrices. However, the absorbed energies were more concentrated in the area closest to the vibrator with decreasing elasticity of the matrix. Softer materials absorbed most of the supplied energy around the point of the vibrator. In contrast, harder materials scattered the external energy over a broad area. CONCLUSIONS The current results are the first report in estimating how the external energy is deeply or distantly transferred into a model skins depending on the elastic moduli of the models skins. In doing so, the results would be potentially useful in predicting the health of cells, tissues and organs exposed to various stimuli.
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Affiliation(s)
- M K Jeong
- Department of Chemical Engineering, Hanyang University, Seoul, 04763, South Korea
| | - C Hwang
- Amorepacific Corporation R&D Center, Yonggu-daero, Yongin, 446-729, South Korea
| | - H Nam
- Amorepacific Corporation R&D Center, Yonggu-daero, Yongin, 446-729, South Korea
| | - Y S Cho
- Amorepacific Corporation R&D Center, Yonggu-daero, Yongin, 446-729, South Korea
| | - B Y Kang
- Amorepacific Corporation R&D Center, Yonggu-daero, Yongin, 446-729, South Korea
| | - E C Cho
- Department of Chemical Engineering, Hanyang University, Seoul, 04763, South Korea
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255
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Wortman T, Hsu F, Slocum A. A Novel Phantom Tissue Model for Skin Elasticity Quantification1. J Med Device 2016. [DOI: 10.1115/1.4033278] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Tyler Wortman
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Felicia Hsu
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Alex Slocum
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
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256
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Morales Hurtado M, de Vries EG, Zeng X, van der Heide E. A tribo-mechanical analysis of PVA-based building-blocks for implementation in a 2-layered skin model. J Mech Behav Biomed Mater 2016; 62:319-332. [PMID: 27236420 DOI: 10.1016/j.jmbbm.2016.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 04/28/2016] [Accepted: 05/02/2016] [Indexed: 01/14/2023]
Abstract
Poly(vinyl) alcohol hydrogel (PVA) is a well-known polymer widely used in the medical field due to its biocompatibility properties and easy manufacturing. In this work, the tribo-mechanical properties of PVA-based blocks are studied to evaluate their suitability as a part of a structure simulating the length scale dependence of human skin. Thus, blocks of pure PVA and PVA mixed with Cellulose (PVA-Cel) were synthesised via freezing/thawing cycles and their mechanical properties were determined by Dynamic Mechanical Analysis (DMA) and creep tests. The dynamic tests addressed to elastic moduli between 38 and 50kPa for the PVA and PVA-Cel, respectively. The fitting of the creep compliance tests in the SLS model confirmed the viscoelastic behaviour of the samples with retardation times of 23 and 16 seconds for the PVA and PVA-Cel, respectively. Micro indentation tests were also achieved and the results indicated elastic moduli in the same range of the dynamic tests. Specifically, values between 45-55 and 56-81kPa were obtained for the PVA and PVA-Cel samples, respectively. The tribological results indicated values of 0.55 at low forces for the PVA decreasing to 0.13 at higher forces. The PVA-Cel blocks showed lower friction even at low forces with values between 0.2 and 0.07. The implementation of these building blocks in the design of a 2-layered skin model (2LSM) is also presented in this work. The 2LSM was stamped with four different textures and their surface properties were evaluated. The hydration of the 2LSM was also evaluated with a corneometer and the results indicated a gradient of hydration comparable to the human skin.
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Affiliation(s)
- M Morales Hurtado
- Surface Technology and Tribology Group, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands.
| | - E G de Vries
- Surface Technology and Tribology Group, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands
| | - X Zeng
- Surface Technology and Tribology Group, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands; Advanced lubricating Materials Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Haike Road 100, Pudong, Shanghai, China
| | - E van der Heide
- Surface Technology and Tribology Group, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands; TU Delft, Faculty of Civil Engineering and Geosciences, Stevinweg 1, 2628 CN Delft, The Netherlands
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257
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Microneedle characterisation: the need for universal acceptance criteria and GMP specifications when moving towards commercialisation. Drug Deliv Transl Res 2016; 5:313-31. [PMID: 26022578 DOI: 10.1007/s13346-015-0237-z] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
With interest in microneedles as a novel drug transdermal delivery system increasing rapidly since the late 1990s (Margetts and Sawyer Contin Educ Anaesthesia Crit Care Pain. 7(5):171-76, 2007), a diverse range of microneedle systems have been fabricated with varying designs and dimensions. However, there are still very few commercially available microneedle products. One major issue regarding microneedle manufacture on an industrial scale is the lack of specific quality standards for this novel dosage form in the context of Good Manufacturing Practice (GMP). A range of mechanical characterisation tests and microneedle insertion analysis techniques are used by researchers working on microneedle systems to assess the safety and performance profiles of their various designs. The lack of standardised tests and equipment used to demonstrate microneedle mechanical properties and insertion capability makes it difficult to directly compare the in use performance of candidate systems. This review highlights the mechanical tests and insertion analytical techniques used by various groups to characterise microneedles. This in turn exposes the urgent need for consistency across the range of microneedle systems in order to promote innovation and the successful commercialisation of microneedle products.
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258
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Cheng X, Edwards N, Leung K, Zhang D, Christy RJ. Preparation and In Vitro Evaluation of Electrochemically-Aligned Collagen Matrix as a Dermal Substitute. ACTA ACUST UNITED AC 2016. [DOI: 10.1557/adv.2016.240] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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259
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Epidermal growth factor loaded heparin-based hydrogel sheet for skin wound healing. Carbohydr Polym 2016; 147:251-260. [PMID: 27178931 DOI: 10.1016/j.carbpol.2016.03.072] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 11/20/2022]
Abstract
A heparin-based hydrogel sheet composed of thiolated heparin and diacrylated poly (ethylene glycol) was prepared via photo polymerization and human epidermal growth factor (hEGF) were loaded into it for the purpose of wound healing. It showed a sustained release profile of hEGF in vitro. In order to evaluate its function on wound healing in vivo, full thickness wounds were created on the dorsal surface of mice. Application of hEGF loaded heparin-based hydrogel sheet accelerated the wound closure compared to the non-treated control group, hEGF solution, and hEGF loaded PEG hydrogel sheet. Histological and immunohistological examinations also demonstrated an advanced granulation tissue formation, capillary formation, and epithelialization in wounds treated by hEGF loaded heparin-based hydrogel compared to other groups, and no biocompatibility issue was observed. In conclusion, the delivery of hEGF using the heparin-based hydrogel could accelerate the skin wound healing process.
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260
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Suaste-Gómez E, Rodríguez-Roldán G, Reyes-Cruz H, Terán-Jiménez O. Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature. SENSORS 2016; 16:s16030332. [PMID: 26959026 PMCID: PMC4813907 DOI: 10.3390/s16030332] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/18/2016] [Accepted: 02/29/2016] [Indexed: 12/03/2022]
Abstract
An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF) for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa) and temperature (2 °C to 90 °C). The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing). More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception.
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Affiliation(s)
- Ernesto Suaste-Gómez
- Department of Electrical Engineering, Section of Bioelectronics, Center for Research and Advanced Studies, CINVESTAV-IPN, Av. IPN 2508, Col. San Pedro Zacatenco, C.P. 07360, D.F., Mexico.
| | - Grissel Rodríguez-Roldán
- Department of Electrical Engineering, Section of Bioelectronics, Center for Research and Advanced Studies, CINVESTAV-IPN, Av. IPN 2508, Col. San Pedro Zacatenco, C.P. 07360, D.F., Mexico.
| | - Héctor Reyes-Cruz
- Department of Electrical Engineering, Section of Bioelectronics, Center for Research and Advanced Studies, CINVESTAV-IPN, Av. IPN 2508, Col. San Pedro Zacatenco, C.P. 07360, D.F., Mexico.
| | - Omar Terán-Jiménez
- Department of Electrical Engineering, Section of Bioelectronics, Center for Research and Advanced Studies, CINVESTAV-IPN, Av. IPN 2508, Col. San Pedro Zacatenco, C.P. 07360, D.F., Mexico.
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261
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Karimi A, Rahmati SM, Navidbakhsh M. Mechanical characterization of the rat and mice skin tissues using histostructural and uniaxial data. Bioengineered 2016; 6:153-60. [PMID: 25837446 DOI: 10.1080/21655979.2015.1036202] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The skin tissue has been shown to behave like a nonlinear anisotropic material. This study was aimed to employ a constitutive fiber family equation to characterize the nonlinear anisotropic mechanical behavior of the rat and mice skin tissues in different anatomical locations, including the abdomen and back, using histostructural and uniaxial data. The rat and mice skin tissues were excised from the animals' body and then the histological analyses were performed on each skin type to determine the mean fiber orientation angle. Afterward, the preconditioned skin tissues were subjected to a series of quasi-static axial and circumferential loads until the incidence of failure. The crucial role of fiber orientation was explicitly added into a proposed strain energy density function. The material coefficients were determined using the constrained nonlinear optimization method based on the axial and circumferential extension data of the rat and mice samples at different anatomical locations. The material coefficients of the skins were given with R(2) ≥ 0.998. The results revealed a significant load-bearing capacity and stiffness of the rat abdomen compared to the rat back tissues. In addition, the mice abdomen showed a higher stiffness in the axial direction in comparison with circumferential one, while the mice back displayed its highest stiffness in the circumferential direction. The material coefficients of the rat and mice skin tissues were determined and well compared to the experimental data. The optimized fiber angles were also compared to the experimental histological data, and in all cases less than 11.85% differences were observed in both the skin tissues.
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Affiliation(s)
- Alireza Karimi
- a School of Mechanical Engineering ; Iran University of Science and Technology ; Tehran , Iran
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262
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Reis TC, Castleberry S, Rego AMB, Aguiar-Ricardo A, Hammond PT. Three-dimensional multilayered fibrous constructs for wound healing applications. Biomater Sci 2016; 4:319-30. [PMID: 26584183 PMCID: PMC4729609 DOI: 10.1039/c5bm00211g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrospun materials are promising scaffolds due to their light-weight, high surface-area and low-cost fabrication, however, such scaffolds are commonly obtained as ultrathin two-dimensional non-woven meshes, lacking on topographical specificity and surface side-dependent properties. Herein, it is reported the production of three-dimensional fibrous materials with an asymmetrical inner structure and engineered surfaces. The manufactured constructs evidence fibrous-based microsized conical protrusions [length: (10 ± 3) × 10(2) μm; width: (3.8 ± 0.8) × 10(2) μm] at their top side, with a median peak density of 73 peaks per cm(2), while their bottom side resembles to a non-woven mesh commonly observed in the fabrication of two-dimensional electrospun materials. Regarding their thickness (3.7 ± 0.1 mm) and asymmetric fibrous inner architecture, such materials avoid external liquid absorption while promoting internal liquid uptake. Nevertheless, such constructs also observed the high porosity (89.9%) and surface area (1.44 m(2) g(-1)) characteristic of traditional electrospun mats. Spray layer-by-layer assembly is used to effectively coat the structurally complex materials, allowing to complementary tailor features such as water vapor transmission, swelling ratio and bioactive agent release. Tested as wound dressings, the novel constructs are capable of withstanding (11.0 ± 0.3) × 10(4) kg m(-2) even after 14 days of hydration, while actively promote wound healing (90 ± 0.5% of wound closure within 48 hours) although avoiding cell adhesion on the dressings for a painless removal.
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Affiliation(s)
- Tiago C Reis
- LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal. and Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - Steven Castleberry
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - Ana M B Rego
- CQFM and IN, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Ana Aguiar-Ricardo
- LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
| | - Paula T Hammond
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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263
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264
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Franzetti G, Crippa F, Cutri E, Spatafora G, Montin E, Mainardi L, Spadola G, Testori A, Pennati G. Combined approach for the biomechanical characterization of skin lesions. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:913-6. [PMID: 26736411 DOI: 10.1109/embc.2015.7318511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Melanocytic nevi are common benign skin lesions, known as moles, due to proliferation of melanocytes, the pigmented skin cells. The uncontrolled growth of these cells leads instead to cutaneous malignant melanoma, an aggressive tumour whose rate of survival dramatically increases if early diagnosis is provided. Alteration on the mechanical properties of the skin in presence of lesions has been assessed. In this context, we aim at developing a combined approach consisting of an experimental and a computational study to biomechanically characterize the skin and both malign and benign skin lesions (i.e., nevi and malignant melanoma). In particular, the former study is performed to evaluate the biomechanical response of the different skin layers after the application of a displacement field and relies on a multi-scale strategy, ranging from the tissue level to the cellular level. Computational models will be tuned against experimental data (e.g., confocal laser scanning microscopy data) to estimate the mechanical properties of the different layers of the skin and the skin lesions. In particular, the confocal laser scanning microscopy is able to provide non-invasive histomorphological analysis of skin in vivo. The integration of the experimental and the computational results will allow the evaluation of possible alterations of the local mechanical properties occurring in case of pathological condition.
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265
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Ventrelli L, Marsilio Strambini L, Barillaro G. Microneedles for Transdermal Biosensing: Current Picture and Future Direction. Adv Healthc Mater 2015; 4:2606-40. [PMID: 26439100 DOI: 10.1002/adhm.201500450] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Indexed: 01/01/2023]
Abstract
A novel trend is rapidly emerging in the use of microneedles, which are a miniaturized replica of hypodermic needles with length-scales of hundreds of micrometers, aimed at the transdermal biosensing of analytes of clinical interest, e.g., glucose, biomarkers, and others. Transdermal biosensing via microneedles offers remarkable opportunities for moving biosensing technologies and biochips from research laboratories to real-field applications, and envisages easy-to-use point-of-care microdevices with pain-free, minimally invasive, and minimal-training features that are very attractive for both developed and emerging countries. In addition to this, microneedles for transdermal biosensing offer a unique possibility for the development of biochips provided with end-effectors for their interaction with the biological system under investigation. Direct and efficient collection of the biological sample to be analyzed will then become feasible in situ at the same length-scale of the other biochip components by minimally trained personnel and in a minimally invasive fashion. This would eliminate the need for blood extraction using hypodermic needles and reduce, in turn, related problems, such as patient infections, sample contaminations, analysis artifacts, etc. The aim here is to provide a thorough and critical analysis of state-of-the-art developments in this novel research trend, and to bridge the gap between microneedles and biosensors.
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Affiliation(s)
- Letizia Ventrelli
- Dipartimento di Ingegneria dell'Informazione; Università di Pisa; Via G. Caruso 16 56122 Pisa Italy
| | | | - Giuseppe Barillaro
- Dipartimento di Ingegneria dell'Informazione; Università di Pisa; Via G. Caruso 16 56122 Pisa Italy
- Istituto di Fisiologia Clinica; Consiglio Nazionale delle Ricerche; via G. Moruzzi 1 56124 Pisa Italy
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266
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Feasibility of Ultra-Thin Fiber-Optic Dosimeters for Radiotherapy Dosimetry. SENSORS 2015; 15:29003-14. [PMID: 26593917 PMCID: PMC4701318 DOI: 10.3390/s151129003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 11/11/2015] [Accepted: 11/12/2015] [Indexed: 11/17/2022]
Abstract
In this study, prototype ultra-thin fiber-optic dosimeters were fabricated using organic scintillators, wavelength shifting fibers, and plastic optical fibers. The sensor probes of the ultra-thin fiber-optic dosimeters consisted of very thin organic scintillators with thicknesses of 100, 150 and 200 μm. These types of sensors cannot only be used to measure skin or surface doses but also provide depth dose measurements with high spatial resolution. With the ultra-thin fiber-optic dosimeters, surface doses for gamma rays generated from a Co-60 therapy machine were measured. Additionally, percentage depth doses in the build-up regions were obtained by using the ultra-thin fiber-optic dosimeters, and the results were compared with those of external beam therapy films and a conventional fiber-optic dosimeter.
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267
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Choi MC, Cheung KK, Ng GYF, Zheng YP, Cheing GLY. Measurement of diabetic wounds with optical coherence tomography-based air-jet indentation system and a material testing system. J Wound Care 2015; 24:519, 522-4, 526-8. [PMID: 26551644 DOI: 10.12968/jowc.2015.24.11.519] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Material testing system is a conventional but destructive method for measuring the biomechanical properties of wound tissues in basic research. The recently developed optical coherence tomography-based air-jet indentation system is a non-destructive method for measuring these properties of soft tissues in a non-contact manner. The aim of the study was to examine the correlation between the biomechanical properties of wound tissues measured by the two systems. METHOD Young male Sprague-Dawley rats with streptozotocin-induced diabetic were wounded by a 6 mm biopsy punch on their hind limbs. The biomechanical properties of wound tissues were assessed with the two systems on post-wounding days 3, 7, 10, 14, and 21. Wound sections were stained with picro-sirius red for analysis on the collagen fibres. Data obtained on the different days were charted to obtain the change in biomechanical properties across the time points, and then pooled to examine the correlation between measurements made by the two devices. Qualitative analysis to determine any correlation between indentation stiffness measured by the air-jet indentation system and the orientation of collagen fibres. RESULTS The indentation stiffness is significantly negatively correlated to the maximum load, maximum tensile stress, and Young's modulus by the material testing system (all p<0.05). The orientation of collagen changes with the indentation stiffness over time. CONCLUSION Our findings support the use of optical coherence tomography-based air-jet indentation system to evaluate the biomechanical properties of wounds in a non-contact manner. It is a potential clinical device to examine the biomechanical properties of chronic wounds in vivo in a repeatable manner.
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Affiliation(s)
- M-C Choi
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - K-K Cheung
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - G Y-F Ng
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Y-P Zheng
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - G L-Y Cheing
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China
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268
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Burger C, Gerber M, du Preez JL, du Plessis J. Optimised transdermal delivery of pravastatin. Int J Pharm 2015; 496:518-25. [PMID: 26505148 DOI: 10.1016/j.ijpharm.2015.10.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/07/2015] [Accepted: 10/09/2015] [Indexed: 11/30/2022]
Abstract
Wiechers' programme "Formulating for Efficacy" initiated a new strategy to optimise the oil phase of topical formulations in order to achieve optimal transdermal drug delivery. This new approach uses the "Delivery Gap Theory" on any active pharmaceutical ingredients (APIs) to test if it could enhance transdermal drug delivery. The aim of the study was to formulate six different semi-solid formulations (three creams and three emulgels) with 2% pravastatin as the API in order to investigate the "Delivery Gap Principle", by determining which formulation would deliver pravastatin best to the target-site (system circulation). The three cream- and three emulgel formulations had different polarities, i.e. a formulation with polarity equal to that of the stratum corneum (optimised), a non-polar (lipophilic)- and a polar (hydrophilic)-formulation. Franz cell diffusion studies were executed over 12h and the optimised emulgel (2.578μg/cm(2)) had the highest median amount per area obtained. Tape stripping followed the diffusion studies and in the stratum corneum-epidermis, the hydrophilic emulgel (1.448μg/ml) contained the highest median pravastatin concentration and the epidermis-dermis the optimised emulgel (0.849μg/ml) depicted the highest pravastatin concentration. During this study, it was observed that when both emulgel and cream formulations were compared; the emulgels enhanced the delivery of pravastatin more than the creams.
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Affiliation(s)
- Cornel Burger
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa
| | - Minja Gerber
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa.
| | - Jan L du Preez
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa
| | - Jeanetta du Plessis
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa
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269
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Kim M, Gweon B, Koh U, Cho Y, Shin DW, Noh M, Shin JH. Matrix stiffness induces epithelial mesenchymal transition phenotypes of human epidermal keratinocytes on collagen coated two dimensional cell culture. Biomed Eng Lett 2015. [DOI: 10.1007/s13534-015-0202-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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270
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Amjadi M, Yoon YJ, Park I. Ultra-stretchable and skin-mountable strain sensors using carbon nanotubes-Ecoflex nanocomposites. NANOTECHNOLOGY 2015; 26:375501. [PMID: 26303117 DOI: 10.1088/0957-4484/26/37/375501] [Citation(s) in RCA: 255] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Super-stretchable, skin-mountable, and ultra-soft strain sensors are presented by using carbon nanotube percolation network-silicone rubber nanocomposite thin films. The applicability of the strain sensors as epidermal electronic systems, in which mechanical compliance like human skin and high stretchability (ϵ > 100%) are required, has been explored. The sensitivity of the strain sensors can be tuned by the number density of the carbon nanotube percolation network. The strain sensors show excellent hysteresis performance at different strain levels and rates with high linearity and small drift. We found that the carbon nanotube-silicone rubber based strain sensors possess super-stretchability and high reliability for strains as large as 500%. The nanocomposite thin films exhibit high robustness and excellent resistance-strain dependency for over ~1380% mechanical strain. Finally, we performed skin motion detection by mounting the strain sensors on different parts of the body. The maximum induced strain by the bending of the finger, wrist, and elbow was measured to be ~ 42%, 45% and 63%, respectively.
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Affiliation(s)
- Morteza Amjadi
- Department of Mechanical Engineering and KI for the NanoCentury (KINC), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Korea
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271
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Adolph EJ, Guo R, Pollins AC, Zienkiewicz K, Cardwell N, Davidson JM, Guelcher SA, Nanney LB. Injected biodegradable polyurethane scaffolds support tissue infiltration and delay wound contraction in a porcine excisional model. J Biomed Mater Res B Appl Biomater 2015; 104:1679-1690. [PMID: 26343927 DOI: 10.1002/jbm.b.33515] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 08/03/2015] [Accepted: 08/23/2015] [Indexed: 11/10/2022]
Abstract
The filling of wound cavities with new tissue is a challenge. We previously reported on the physical properties and wound healing kinetics of prefabricated, gas-blown polyurethane (PUR) scaffolds in rat and porcine excisional wounds. To address the capability of this material to fill complex wound cavities, this study examined the in vitro and in vivo reparative characteristics of injected PUR scaffolds employing a sucrose porogen. Using the porcine excisional wound model, we compared reparative outcomes to both preformed and injected scaffolds as well as untreated wounds at 9, 13, and 30 days after scaffold placement. Both injected and preformed scaffolds delayed wound contraction by 19% at 9 days and 12% at 13 days compared to nontreated wounds. This stenting effect proved transient since both formulations degraded by day 30. Both types of scaffolds significantly inhibited the undesirable alignment of collagen and fibroblasts through day 13. Injected scaffolds were highly compatible with sentinel cellular events of normal wound repair cell proliferation, apoptosis, and blood vessel density. The present study provides further evidence that either injected or preformed PUR scaffolds facilitate wound healing, support tissue infiltration and matrix production, delay wound contraction, and reduce scarring in a clinically relevant animal model, which underscores their potential utility as a void-filling platform for large cutaneous defects. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1679-1690, 2016.
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Affiliation(s)
- Elizabeth J Adolph
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee
| | - Ruijing Guo
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee
| | - Alonda C Pollins
- Department of Plastic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Katarzyna Zienkiewicz
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee
| | - Nancy Cardwell
- Department of Plastic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jeffrey M Davidson
- Research Service, VA Tennessee Valley Healthcare System, Nashville, Tennessee.,Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Scott A Guelcher
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee.,Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lillian B Nanney
- Department of Plastic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee. .,Department of Cell & Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee.
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272
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Cornuault PH, Carpentier L, Bueno MA, Cote JM, Monteil G. Influence of physico-chemical, mechanical and morphological fingerpad properties on the frictional distinction of sticky/slippery surfaces. J R Soc Interface 2015; 12:0495. [PMID: 26269232 PMCID: PMC4614458 DOI: 10.1098/rsif.2015.0495] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 07/17/2015] [Indexed: 01/29/2023] Open
Abstract
This study investigates how the fingerpad hydrolipid film, shape, roughness and rigidity influence the friction when it rubs surfaces situated in the slippery psychophysical dimension. The studied counterparts comprised two 'real' (physical) surfaces and two 'virtual' surfaces. The latter were simulated with a tactile stimulator named STIMTAC. Thirteen women and 13 men rubbed their right forefingers against the different surfaces as their arms were displaced by a DC motor providing constant velocity and sliding distance. Tangential and normal forces were measured with a specific tribometer. The fingerpad hydrolipid film was characterized by Fourier transform infrared spectroscopy. The shape and roughness of fingers were extrapolated from replicas. Indentation measurements were carried out to determine fingerpad effective elastic modulus. A clear difference was observed between women and men in terms of friction behaviour. The concept of tactile frictional contrast (TFC) which was introduced quantifies an individual's propensity to distinguish two surfaces frictionally. The lipids/water ratio and water amount on the finger skin significantly influenced the TFC. A correlation was observed between the TFC and fingerpad roughness, i.e. the height of the fingerpad ridges. This is essentially owing to gender differences. A significant difference between men's and women's finger topography was also noted, because our results suggested that men have rougher fingers than women. The friction measurements did not correlate with the fingerpad curvature nor with the epidermal ridges' spatial period.
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Affiliation(s)
- Pierre-Henri Cornuault
- Département de Mécanique Appliquée, Institut FEMTO-ST, UMR CNRS 6174, UBFC, 24 rue de l'Epitaphe, 25000 Besançon, France
| | - Luc Carpentier
- Département de Mécanique Appliquée, Institut FEMTO-ST, UMR CNRS 6174, UBFC, 24 rue de l'Epitaphe, 25000 Besançon, France
| | - Marie-Ange Bueno
- Laboratoire de Physique et Mécanique Textiles, Université Haute-Alsace, Ecole Nationale Supérieure d'Ingénieurs Sud Alsace, 11 rue Alfred Werner, 68093 Mulhouse Cedex, France
| | - Jean-Marc Cote
- Département de Mécanique Appliquée, Institut FEMTO-ST, UMR CNRS 6174, UBFC, 24 rue de l'Epitaphe, 25000 Besançon, France
| | - Guy Monteil
- Département de Mécanique Appliquée, Institut FEMTO-ST, UMR CNRS 6174, UBFC, 24 rue de l'Epitaphe, 25000 Besançon, France
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273
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Liu X, German G. The effects of barrier disruption and moisturization on the dynamic drying mechanics of human stratum corneum. J Mech Behav Biomed Mater 2015; 49:80-9. [DOI: 10.1016/j.jmbbm.2015.04.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/14/2015] [Accepted: 04/16/2015] [Indexed: 10/23/2022]
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274
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Kawano S, Kojima M, Higuchi Y, Sugimoto M, Ikeda K, Sakuyama N, Takahashi S, Hayashi R, Ochiai A, Saito N. Assessment of elasticity of colorectal cancer tissue, clinical utility, pathological and phenotypical relevance. Cancer Sci 2015; 106:1232-9. [PMID: 26083008 PMCID: PMC4582994 DOI: 10.1111/cas.12720] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/29/2015] [Accepted: 06/06/2015] [Indexed: 12/21/2022] Open
Abstract
Generally, cancer tissue is palpated as a hard mass. However, the elastic nature of cancer tissue is not well understood. The aim of the present study was to evaluate the clinical utility of measuring the elastic modulus (EM) in colorectal cancer tissue. Using a tactile sensor, we measured the EM of 106 surgically resected colorectal cancer tissues. Data on the EM were compared with clinicopathological findings, including stromal features represented by Azan staining and the α-SMA positive area ratio of the tumor area. Finally, a cDNA microarray profile of the tumors with high EM were compared with the findings of tumors with low EM. A higher EM in tumors was associated with pathological T, N, and M-stage tumors (P < 0.001, P = 0.001 and P = 0.011, respectively). Patients with high EM tumors had shorter disease-free survival than had patients with low EM. The EM showed strongly positive correlation with the Azan staining positive area ratio (r = 0.908) and the α-SMA positive area ratio (r = 0.921). Finally, the cDNA microarray data of the tumors with high EM revealed a distinct gene expression profile compared with data from those tumors with low EM. The assessment of the elasticity of colorectal cancer tissue may allow a more accurate clinical stage and prognosis estimation. The distinct phenotypical features of the high EM tumors and their strong association with stromal features suggest the existence of a biological mechanism involved in this phenomenon that may contribute to future therapy.
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Affiliation(s)
- Shingo Kawano
- Department of Colorectal and Pelvic Surgery, National Cancer Center Hospital East, Chiba, Japan.,Advanced Clinical Research of Cancer, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Motohiro Kojima
- Division of Pathology, Research Center for Innovative Oncology, National Cancer Center Hospital East, Chiba, Japan
| | - Yoichi Higuchi
- Division of Pathology, Research Center for Innovative Oncology, National Cancer Center Hospital East, Chiba, Japan
| | - Motokazu Sugimoto
- Department of Hepatobiliary-Pancreatic Surgery, National Cancer Center Hospital East, Chiba, Japan
| | - Koji Ikeda
- Department of Colorectal and Pelvic Surgery, National Cancer Center Hospital East, Chiba, Japan
| | - Naoki Sakuyama
- Department of Colorectal and Pelvic Surgery, National Cancer Center Hospital East, Chiba, Japan
| | - Shinichiro Takahashi
- Department of Hepatobiliary-Pancreatic Surgery, National Cancer Center Hospital East, Chiba, Japan
| | - Ryuichi Hayashi
- Advanced Clinical Research of Cancer, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Department of Head and Neck Surgery, National Cancer Center Hospital East, Chiba, Japan
| | - Atsushi Ochiai
- Division of Pathology, Research Center for Innovative Oncology, National Cancer Center Hospital East, Chiba, Japan
| | - Norio Saito
- Department of Colorectal and Pelvic Surgery, National Cancer Center Hospital East, Chiba, Japan
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275
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Akhmanova M, Osidak E, Domogatsky S, Rodin S, Domogatskaya A. Physical, Spatial, and Molecular Aspects of Extracellular Matrix of In Vivo Niches and Artificial Scaffolds Relevant to Stem Cells Research. Stem Cells Int 2015; 2015:167025. [PMID: 26351461 PMCID: PMC4553184 DOI: 10.1155/2015/167025] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/07/2015] [Accepted: 06/24/2015] [Indexed: 12/27/2022] Open
Abstract
Extracellular matrix can influence stem cell choices, such as self-renewal, quiescence, migration, proliferation, phenotype maintenance, differentiation, or apoptosis. Three aspects of extracellular matrix were extensively studied during the last decade: physical properties, spatial presentation of adhesive epitopes, and molecular complexity. Over 15 different parameters have been shown to influence stem cell choices. Physical aspects include stiffness (or elasticity), viscoelasticity, pore size, porosity, amplitude and frequency of static and dynamic deformations applied to the matrix. Spatial aspects include scaffold dimensionality (2D or 3D) and thickness; cell polarity; area, shape, and microscale topography of cell adhesion surface; epitope concentration, epitope clustering characteristics (number of epitopes per cluster, spacing between epitopes within cluster, spacing between separate clusters, cluster patterns, and level of disorder in epitope arrangement), and nanotopography. Biochemical characteristics of natural extracellular matrix molecules regard diversity and structural complexity of matrix molecules, affinity and specificity of epitope interaction with cell receptors, role of non-affinity domains, complexity of supramolecular organization, and co-signaling by growth factors or matrix epitopes. Synergy between several matrix aspects enables stem cells to retain their function in vivo and may be a key to generation of long-term, robust, and effective in vitro stem cell culture systems.
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Affiliation(s)
| | - Egor Osidak
- Imtek Limited, 3 Cherepkovskaya 15, Moscow 21552, Russia
- Gamaleya Research Institute of Epidemiology and Microbiology Federal State Budgetary Institution, Ministry of Health of the Russian Federation, Gamalei 18, Moscow 123098, Russia
| | - Sergey Domogatsky
- Imtek Limited, 3 Cherepkovskaya 15, Moscow 21552, Russia
- Russian Cardiology Research and Production Center Federal State Budgetary Institution, Ministry of Health of the Russian Federation, 3 Cherepkovskaya 15, Moscow 21552, Russia
| | - Sergey Rodin
- Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77 Stockholm, Sweden
| | - Anna Domogatskaya
- Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77 Stockholm, Sweden
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276
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Breathable and Stretchable Temperature Sensors Inspired by Skin. Sci Rep 2015; 5:11505. [PMID: 26095941 PMCID: PMC4476093 DOI: 10.1038/srep11505] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 05/26/2015] [Indexed: 12/23/2022] Open
Abstract
Flexible electronics attached to skin for healthcare, such as epidermal electronics, has to struggle with biocompatibility and adapt to specified environment of skin with respect to breath and perspiration. Here, we report a strategy for biocompatible flexible temperature sensors, inspired by skin, possessing the excellent permeability of air and high quality of water-proof by using semipermeable film with porous structures as substrate. We attach such temperature sensors to underarm and forearm to measure the axillary temperature and body surface temperature respectively. The volunteer wears such sensors for 24 hours with two times of shower and the in vitro test shows no sign of maceration or stimulation to the skin. Especially, precise temperature changes on skin surface caused by flowing air and water dropping are also measured to validate the accuracy and dynamical response. The results show that the biocompatible temperature sensor is soft and breathable on the human skin and has the excellent accuracy compared to mercury thermometer. This demonstrates the possibility and feasibility of fully using the sensors in long term body temperature sensing for medical use as well as sensing function of artificial skin for robots or prosthesis.
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277
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Luo CC, Qian LX, Li GY, Jiang Y, Liang S, Cao Y. Determining thein vivoelastic properties of dermis layer of human skin using the supersonic shear imaging technique and inverse analysis. Med Phys 2015; 42:4106-15. [DOI: 10.1118/1.4922133] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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278
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Fang G, Köppl A. FEM simulation of single beard hair cutting with foil–blade-shaving system. J Mech Behav Biomed Mater 2015; 46:271-84. [DOI: 10.1016/j.jmbbm.2015.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 03/04/2015] [Accepted: 03/08/2015] [Indexed: 10/23/2022]
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279
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Morales-Hurtado M, Zeng X, Gonzalez-Rodriguez P, Ten Elshof J, van der Heide E. A new water absorbable mechanical Epidermal skin equivalent: The combination of hydrophobic PDMS and hydrophilic PVA hydrogel. J Mech Behav Biomed Mater 2015; 46:305-17. [DOI: 10.1016/j.jmbbm.2015.02.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 01/19/2015] [Accepted: 02/18/2015] [Indexed: 10/23/2022]
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280
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Pavan PG, Pachera P, Stecco C, Natali AN. Biomechanical behavior of human crural fascia in anterior and posterior regions of the lower limb. Med Biol Eng Comput 2015; 53:951-9. [PMID: 25980504 DOI: 10.1007/s11517-015-1308-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 05/04/2015] [Indexed: 12/11/2022]
Abstract
The present work focuses on the numerical modeling of the mechanical behavior of the crural fascia, the deep fascia enwrapping the lower limb muscles. This fascia has an important biomechanical role, due to its interaction with muscles during contraction and its association with pathological events, such as compartment syndrome. The mechanical response of the crural fascia is described by assuming a hyperelastic fiber-reinforced constitutive model, with families of fibers disposed according to the spatial disposition of the collagen network, as shown in histological analyses. A two-dimensional finite element model of a lower limb transversal section has been developed to analyze deformational behavior, with particular attention on interaction phenomena between crural fascia and enwrapped muscles. The constitutive model adopted for the crural fascia well fits experimental data taken along the proximal-distal and medial-lateral directions. The finite element analysis allows for interpreting the relation between change in volume and pressure of muscle compartments and the crural fascia deformation.
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Affiliation(s)
- Piero G Pavan
- Department of Industrial Engineering, University of Padova, Via G. Marzolo 9, 35131, Padova, Italia, Italy. .,Centre of Mechanics of Biological Materials, University of Padova, Via G. Colombo 3, 35131, Padova, Italy.
| | - Paola Pachera
- Department of Industrial Engineering, University of Padova, Via G. Marzolo 9, 35131, Padova, Italia, Italy.,Centre of Mechanics of Biological Materials, University of Padova, Via G. Colombo 3, 35131, Padova, Italy
| | - Carla Stecco
- Department of Molecular Medicine, University of Padova, via A. Gabelli 63 3, 35131, Padova, Italy.,Centre of Mechanics of Biological Materials, University of Padova, Via G. Colombo 3, 35131, Padova, Italy
| | - Arturo N Natali
- Department of Industrial Engineering, University of Padova, Via G. Marzolo 9, 35131, Padova, Italia, Italy.,Centre of Mechanics of Biological Materials, University of Padova, Via G. Colombo 3, 35131, Padova, Italy
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281
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Full-surface deformation measurement of anisotropic tissues under indentation. Med Eng Phys 2015; 37:484-93. [PMID: 25857545 DOI: 10.1016/j.medengphy.2015.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 03/17/2015] [Accepted: 03/17/2015] [Indexed: 11/20/2022]
Abstract
Inverse finite element-based analysis of soft biological tissues is an important tool to investigate their complex mechanical behavior and to develop physical models for medical simulations. Although there have recently been advances in dealing with the computational complexities of modeling biological materials, the collection of a sufficiently dense set of experimental data to properly capture their typically regionally varying properties still remains a critical issue. The aim of this work was to develop and test an optical system that combines 2D-Digital Image Correlation (DIC) and a novel Fringe Projection method with radial sensitivity (RFP) to test soft biological tissues under in vitro indentation. This system has the distinctive capability of using a single camera to retrieve the shape and 3D deformation of the whole upper surface of the indented sample without any blind measurement areas (with exception of the area under the indenter), with nominal depth and in-plane resolution of 0.05 mm and 0.004 mm, respectively. To test and illustrate the capabilities of the developed DIC/RFP system, the in vitro response to indentation of a homogeneous and isotropic latex foam is presented against the response of a slab of porcine ventricular myocardium, a highly in-homogeneous and anisotropic tissue. Our results illustrate the enhanced capabilities of the developed method to capture asymmetry in deformation with respect to standard indentation tests. This feature, together with the possibility of miniaturizing the system into a hand-held probe, makes this method potentially extendable to in vivo settings, alone or in combination with ultrasound measurements.
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282
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Thermal and elastic response of subcutaneous tissue with different fibrous septa architectures to RF heating: Numerical study. Lasers Surg Med 2015; 47:183-95. [DOI: 10.1002/lsm.22301] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2014] [Indexed: 11/07/2022]
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283
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Moronkeji K, Akhtar R. Mechanical Properties of Aging Human Skin. ENGINEERING MATERIALS AND PROCESSES 2015. [DOI: 10.1007/978-3-319-03970-1_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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284
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Payne T, Mitchell S, Bibb R, Waters M. The evaluation of new multi-material human soft tissue simulants for sports impact surrogates. J Mech Behav Biomed Mater 2015; 41:336-56. [DOI: 10.1016/j.jmbbm.2014.09.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 09/03/2014] [Accepted: 09/19/2014] [Indexed: 10/24/2022]
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285
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Es'haghian S, Kennedy KM, Gong P, Sampson DD, McLaughlin RA, Kennedy BF. Optical palpation in vivo: imaging human skin lesions using mechanical contrast. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:16013. [PMID: 25588164 DOI: 10.1117/1.jbo.20.1.016013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 12/04/2014] [Indexed: 05/02/2023]
Abstract
We demonstrate the first application of the recently proposed method of optical palpation to in vivo imaging of human skin. Optical palpation is a tactile imaging technique that probes the spatial variation of a sample's mechanical properties by producing an en face map of stress measured at the sample surface. This map is determined from the thickness of a translucent, compliant stress sensor placed between a loading element and the sample and is measured using optical coherence tomography. We assess the performance of optical palpation using a handheld imaging probe on skin-mimicking phantoms, and demonstrate its use on human skin lesions. Our results demonstrate the capacity of optical palpation to delineate the boundaries of lesions and to map the mechanical contrast between lesions and the surrounding normal skin.
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Affiliation(s)
- Shaghayegh Es'haghian
- The University of Western Australia, School of Electrical, Electronic and Computer Engineering, Optical+Biomedical Engineering Laboratory, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Kelsey M Kennedy
- The University of Western Australia, School of Electrical, Electronic and Computer Engineering, Optical+Biomedical Engineering Laboratory, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Peijun Gong
- The University of Western Australia, School of Electrical, Electronic and Computer Engineering, Optical+Biomedical Engineering Laboratory, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - David D Sampson
- The University of Western Australia, School of Electrical, Electronic and Computer Engineering, Optical+Biomedical Engineering Laboratory, 35 Stirling Highway, Crawley, Western Australia 6009, AustraliabThe University of Western Australia, Centre for Micr
| | - Robert A McLaughlin
- The University of Western Australia, School of Electrical, Electronic and Computer Engineering, Optical+Biomedical Engineering Laboratory, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Brendan F Kennedy
- The University of Western Australia, School of Electrical, Electronic and Computer Engineering, Optical+Biomedical Engineering Laboratory, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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286
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Isaza J, Ramirez J. Incidence of Temperature and Indenter Diameter on the Mechanical Response of Skin during Indentation Test. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.proeng.2015.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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287
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Vellayappan MV, Jaganathan SK, Supriyanto E. Review: unraveling the less explored flocking technology for tissue engineering scaffolds. RSC Adv 2015. [DOI: 10.1039/c5ra11937e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The flocking technology is may be further exploited for fabrication of scaffolds for biomedical applications like artificial skin, extra-corporeal organs, articular cartilage etc.
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Affiliation(s)
- M. V. Vellayappan
- IJN-UTM Cardiovascular Engineering Centre
- Faculty of Bioscience and Medical Engineering
- Universiti Teknologi Malaysia
- Malaysia
| | - S. K. Jaganathan
- IJN-UTM Cardiovascular Engineering Centre
- Faculty of Bioscience and Medical Engineering
- Universiti Teknologi Malaysia
- Malaysia
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288
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Pan JF, Liu NH, Sun H, Xu F. Preparation and characterization of electrospun PLCL/Poloxamer nanofibers and dextran/gelatin hydrogels for skin tissue engineering. PLoS One 2014; 9:e112885. [PMID: 25405611 PMCID: PMC4236104 DOI: 10.1371/journal.pone.0112885] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/16/2014] [Indexed: 11/18/2022] Open
Abstract
In this study, two different biomaterials were fabricated and their potential use as a bilayer scaffold for skin tissue engineering applications was assessed. The upper layer biomaterial was a Poly(ε-caprolactone-co-lactide)/Poloxamer (PLCL/Poloxamer) nanofiber membrane fabricated using electrospinning technology. The PLCL/Poloxamer nanofibers (PLCL/Poloxamer, 9/1) exhibited strong mechanical properties (stress/strain values of 9.37 ± 0.38 MPa/187.43 ± 10.66%) and good biocompatibility to support adipose-derived stem cells proliferation. The lower layer biomaterial was a hydrogel composed of 10% dextran and 20% gelatin without the addition of a chemical crosslinking agent. The 5/5 dextran/gelatin hydrogel displayed high swelling property, good compressive strength, capacity to present more than 3 weeks and was able to support cells proliferation. A bilayer scaffold was fabricated using these two materials by underlaying the nanofibers and casting hydrogel to mimic the structure and biological function of native skin tissue. The upper layer membrane provided mechanical support in the scaffold and the lower layer hydrogel provided adequate space to allow cells to proliferate and generate extracellular matrix. The biocompatibility of bilayer scaffold was preliminarily investigated to assess the potential cytotoxicity. The results show that cell viability had not been affected when cocultured with bilayer scaffold. As a consequence, the bilayer scaffold composed of PLCL/Poloxamer nanofibers and dextran/gelatin hydrogels is biocompatible and possesses its potentially high application prospect in the field of skin tissue engineering.
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Affiliation(s)
- Jian-feng Pan
- Department of Orthopaedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Ning-hua Liu
- Department of Orthopaedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Hui Sun
- Department of Orthopaedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Feng Xu
- Department of Orthopaedics, Kunshan Traditional Chinese Medical Hospital, Suzhou, Jiangsu, China
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289
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Tepole AB, Gart M, Gosain AK, Kuhl E. Characterization of living skin using multi-view stereo and isogeometric analysis. Acta Biomater 2014; 10:4822-4831. [PMID: 25016279 PMCID: PMC4186913 DOI: 10.1016/j.actbio.2014.06.037] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 06/17/2014] [Accepted: 06/25/2014] [Indexed: 11/18/2022]
Abstract
Skin is our interface with the outside world. In its natural environment, it displays unique mechanical characteristics, such as prestretch and growth. While there is a general agreement on the physiological importance of these features, they remain poorly characterized, mainly because they are difficult to access with standard laboratory techniques. Here we present a new, inexpensive technique to characterize living skin using multi-view stereo and isogeometric analysis. Based on easy-to-create hand-held camera images, we quantify prestretch, deformation and growth in a controlled porcine model of chronic skin expansion. Over a period of 5 weeks, we gradually inflate an implanted tissue expander, take weekly photographs of the experimental scene, reconstruct the geometry from a tattooed surface grid and create parametric representations of the skin surface. After 5 weeks of expansion, our method reveals an average area prestretch of 1.44, an average area stretch of 1.87 and an average area growth of 2.25. Area prestretch is maximal in the ventral region with a value of 2.37, whereas area stretch and area growth are maximal above the center of the expander, with values of 4.05 and 4.81, respectively. Our study has immediate impact on understanding living skin to optimize treatment planning and decision making in plastic and reconstructive surgery. Beyond these direct implications, our experimental design has broad applications in clinical research and basic sciences: it serves as a simple, robust, low cost, easy-to-use tool to reconstruct living membranes, which are difficult to characterize in a conventional laboratory setup.
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Affiliation(s)
| | - Michael Gart
- Division of Pediatric Plastic Surgery, Lurie Children's Hospital of Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Arun K Gosain
- Division of Pediatric Plastic Surgery, Lurie Children's Hospital of Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ellen Kuhl
- Departments of Mechanical Engineering, Bioengineering, and Cardiothoracic Surgery, Stanford University, Stanford, CA 94305, USA.
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290
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Palacio-Torralba J, Hammer S, Good DW, Alan McNeill S, Stewart GD, Reuben RL, Chen Y. Quantitative diagnostics of soft tissue through viscoelastic characterization using time-based instrumented palpation. J Mech Behav Biomed Mater 2014; 41:149-60. [PMID: 25460411 DOI: 10.1016/j.jmbbm.2014.09.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/18/2014] [Accepted: 09/23/2014] [Indexed: 10/24/2022]
Abstract
Although palpation has been successfully employed for centuries to assess soft tissue quality, it is a subjective test, and is therefore qualitative and depends on the experience of the practitioner. To reproduce what the medical practitioner feels needs more than a simple quasi-static stiffness measurement. This paper assesses the capacity of dynamic mechanical palpation to measure the changes in viscoelastic properties that soft tissue can exhibit under certain pathological conditions. A diagnostic framework is proposed to measure elastic and viscous behaviors simultaneously using a reduced set of viscoelastic parameters, giving a reliable index for quantitative assessment of tissue quality. The approach is illustrated on prostate models reconstructed from prostate MRI scans. The examples show that the change in viscoelastic time constant between healthy and cancerous tissue is a key index for quantitative diagnostics using point probing. The method is not limited to any particular tissue or material and is therefore useful for tissue where defining a unique time constant is not trivial. The proposed framework of quantitative assessment could become a useful tool in clinical diagnostics for soft tissue.
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Affiliation(s)
- Javier Palacio-Torralba
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Steven Hammer
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Daniel W Good
- Edinburgh Urological Cancer Group, Division of Pathology Laboratories, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - S Alan McNeill
- Edinburgh Urological Cancer Group, Division of Pathology Laboratories, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK; Department of Urology, NHS Lothian, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Grant D Stewart
- Edinburgh Urological Cancer Group, Division of Pathology Laboratories, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK; Department of Urology, NHS Lothian, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Robert L Reuben
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Yuhang Chen
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.
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291
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Faturechi R, Karimi A, Hashemi A, Yousefi H, Navidbakhsh M. Influence of Poly(acrylic acid) on the Mechanical Properties of Composite Hydrogels. ADVANCES IN POLYMER TECHNOLOGY 2014. [DOI: 10.1002/adv.21487] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Rahim Faturechi
- Biomedical Engineering Department; Amirkabir University of Technology; Tehran 15875 Iran
- Physico-Mechanical Characterization of Biomaterials Laboratory; Biomedical Engineering Department; Amirkabir University of Technology; Tehran 15875 Iran
| | - Alireza Karimi
- School of Mechanical Engineering; Iran University of Science and Technology; Tehran 16846 Iran
- Tissue Engineering and Biological Systems Research Laboratory; School of Mechanical Engineering; Iran University of Science and Technology; Tehran 16846 Iran
| | - Ata Hashemi
- Biomedical Engineering Department; Amirkabir University of Technology; Tehran 15875 Iran
- Physico-Mechanical Characterization of Biomaterials Laboratory; Biomedical Engineering Department; Amirkabir University of Technology; Tehran 15875 Iran
| | - Hossein Yousefi
- Faculty of New Sciences and Technologies; University of Tehran; Tehran 14395 Iran
| | - Mahdi Navidbakhsh
- School of Mechanical Engineering; Iran University of Science and Technology; Tehran 16846 Iran
- Tissue Engineering and Biological Systems Research Laboratory; School of Mechanical Engineering; Iran University of Science and Technology; Tehran 16846 Iran
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292
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Sugimoto M, Takahashi S, Kojima M, Gotohda N, Kato Y, Kawano S, Ochiai A, Konishi M. What is the nature of pancreatic consistency? Assessment of the elastic modulus of the pancreas and comparison with tactile sensation, histology, and occurrence of postoperative pancreatic fistula after pancreaticoduodenectomy. Surgery 2014; 156:1204-11. [PMID: 25444318 DOI: 10.1016/j.surg.2014.05.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 05/16/2014] [Indexed: 12/21/2022]
Abstract
BACKGROUND Although pancreatic consistency is a factor known to have an impact on the occurrence of postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD), it usually is assessed subjectively by the surgeon. Measurement of the elastic modulus (EM), a parameter characterizing the elasticity of a material, may be one approach for achieving objective and quantitative assessment of pancreatic consistency. This study was conducted to investigate the utility of determining the EM of the pancreas. METHODS Fifty-nine patients who underwent PD and measurement of the EM of the ex vivo pancreas were investigated. Data for EM were compared with the tactile evaluation made by surgeons, histologic findings, and the occurrence of POPF. RESULTS The EM of the pancreas was correlated with the tactile evaluation made by the surgeon (soft pancreas, 1.4 ± 2.1 kPa vs hard pancreas, 4.4 ± 5.1 kPa; P < .001). An EM of >3.0 kPa was correlated with histologic findings including increased ratios of azan-Mallory positivity (P = .003) and α-smooth muscle actin positivity (P = .006), a decreased lobular ratio (P = .021), and an increased vessel density (P < .001). Patients with a pancreatic EM of <3.0 kPa had an increased risk of POPF (hazard ratio, 9.333; P = .002). CONCLUSION Assessment of the EM of the resected pancreas reflects the tactile evaluation made by the surgeon and histological degree of pancreatic fibrosis, and is correlated with the occurrence of POPF after PD.
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Affiliation(s)
- Motokazu Sugimoto
- Department of Hepatobiliary-Pancreatic Surgery, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan; Division of Pathology, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Shinichiro Takahashi
- Department of Hepatobiliary-Pancreatic Surgery, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
| | - Motohiro Kojima
- Division of Pathology, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Naoto Gotohda
- Department of Hepatobiliary-Pancreatic Surgery, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Yuichiro Kato
- Department of Hepatobiliary-Pancreatic Surgery, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Shingo Kawano
- Division of Pathology, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Atsushi Ochiai
- Division of Pathology, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Masaru Konishi
- Department of Hepatobiliary-Pancreatic Surgery, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
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293
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Ottenio M, Tran D, Ní Annaidh A, Gilchrist MD, Bruyère K. Strain rate and anisotropy effects on the tensile failure characteristics of human skin. J Mech Behav Biomed Mater 2014; 41:241-50. [PMID: 25455608 DOI: 10.1016/j.jmbbm.2014.10.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 10/06/2014] [Accepted: 10/08/2014] [Indexed: 10/24/2022]
Abstract
The anisotropic failure characteristics of human skin are relatively unknown at strain rates typical in impact biomechanics. This study reports the results of an experimental protocol to quantify the effect of dynamic strain rates and the effect of sample orientation with respect to the Langer lines. Uniaxial tensile tests were carried out at three strain rates (0.06s(-1), 53s(-1), and 167s(-1)) on 33 test samples excised from the back of a fresh cadaver. The mean ultimate tensile stress, mean elastic modulus and mean strain energy increased with increasing strain rates. While the stretch ratio at ultimate tensile stress was not affected by the strain rate, it was influenced by the orientation of the samples (parallel and perpendicular to the Langer lines. The orientation of the sample also had a strong influence on the ultimate tensile stress, with a mean value of 28.0 ± 5.7 MPa for parallel samples, and 15.6 ± 5.2 MPa for perpendicular samples, and on the elastic modulus, with corresponding mean values of 160.8 MPa ± 53.2 MPa and 70.6 MPa ± 59.5 MPa. The study also pointed out the difficulties in controlling the effective applied strain rate in dynamic characterization of soft tissue and the resulting abnormal stress-strain relationships. Finally, data collected in this study can be used to develop constitutive models where high loading rates are of primary interest.
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Affiliation(s)
- Mélanie Ottenio
- Université de Lyon, F-69622, Lyon, France; Université Claude Bernard Lyon 1, Villeurbanne, France; IFSTTAR, UMR_T9406, LBMC Laboratoire de Biomécanique et Mécanique des Chocs, F69675, Bron, France.
| | - Doris Tran
- Université de Lyon, F-69622, Lyon, France; Université Claude Bernard Lyon 1, Villeurbanne, France; IFSTTAR, UMR_T9406, LBMC Laboratoire de Biomécanique et Mécanique des Chocs, F69675, Bron, France
| | - Aisling Ní Annaidh
- School of Mechanical & Materials Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michael D Gilchrist
- School of Mechanical & Materials Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Karine Bruyère
- Université de Lyon, F-69622, Lyon, France; Université Claude Bernard Lyon 1, Villeurbanne, France; IFSTTAR, UMR_T9406, LBMC Laboratoire de Biomécanique et Mécanique des Chocs, F69675, Bron, France
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294
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Rheological behaviour of reconstructed skin. J Mech Behav Biomed Mater 2014; 37:251-63. [DOI: 10.1016/j.jmbbm.2014.05.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 05/16/2014] [Accepted: 05/27/2014] [Indexed: 12/11/2022]
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295
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Tepole AB, Gosain AK, Kuhl E. Computational modeling of skin: Using stress profiles as predictor for tissue necrosis in reconstructive surgery. COMPUTERS & STRUCTURES 2014; 143:32-39. [PMID: 25225454 PMCID: PMC4162094 DOI: 10.1016/j.compstruc.2014.07.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Local skin flaps have revolutionized reconstructive surgery. Mechanical loading is critical for flap survival: Excessive tissue tension reduces blood supply and induces tissue necrosis. However, skin flaps have never been analyzed mechanically. Here we explore the stress profiles of two common flap designs, direct advancement flaps and double back-cut flaps. Our simulations predict a direct correlation between regions of maximum stress and tissue necrosis. This suggests that elevated stress could serve as predictor for flap failure. Our model is a promising step towards computer-guided reconstructive surgery with the goal to minimize stress, accelerate healing, minimize scarring, and optimize tissue use.
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Affiliation(s)
| | - Arun K. Gosain
- Division of Pediatric Plastic Surgery, Lurie Children's Hospital of Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ellen Kuhl
- Departments of Mechanical Engineering, Bioengineering, and Cardiothoracic Surgery, Stanford University, Stanford, CA 94305, USA
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296
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Zhu Y, Zhang X, Zheng Y, Chen X, Shen Y, Lin H, Guo Y, Wang T, Chen S. Quantitative analysis of liver fibrosis in rats with shearwave dispersion ultrasound vibrometry: comparison with dynamic mechanical analysis. Med Eng Phys 2014; 36:1401-7. [PMID: 24835187 DOI: 10.1016/j.medengphy.2014.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 04/02/2014] [Accepted: 04/04/2014] [Indexed: 12/19/2022]
Abstract
Ultrasonic elastography, a non-invasive technique for assessing the elasticity properties of tissues, has shown promising results for disease diagnosis. However, biological soft tissues are viscoelastic in nature. Shearwave dispersion ultrasound vibrometry (SDUV) can simultaneously measure the elasticity and viscosity of tissue using shear wave propagation speeds at different frequencies. In this paper, the viscoelasticity of rat livers was measured quantitatively by SDUV for normal (stage F0) and fibrotic livers (stage F2). Meanwhile, an independent validation study was presented in which SDUV results were compared with those derived from dynamic mechanical analysis (DMA), which is the only mechanical test that simultaneously assesses the viscoelastic properties of tissue. Shear wave speeds were measured at frequencies of 100, 200, 300 and 400 Hz with SDUV and the storage moduli and loss moduli were measured at the frequency range of 1-40 Hz with DMA. The Voigt viscoelastic model was used in the two methods. The mean elasticity and viscosity obtained by SDUV ranged from 0.84±0.13 kPa (F0) to 1.85±0.30 kPa (F2) and from 1.12±0.11 Pa s (F0) to 1.70±0.31 Pa s (F2), respectively. The mean elasticity and viscosity derived from DMA ranged from 0.62±0.09 kPa (F0) to 1.70±0.84 kPa (F2) and from 3.38±0.32 Pa s (F0) to 4.63±1.30 Pa s (F2), respectively. Both SDUV and DMA demonstrated that the elasticity of rat livers increased from stage F0 to F2, a finding which was consistent with previous literature. However, the elasticity measurements obtained by SDUV had smaller differences than those obtained by DMA, whereas the viscosities obtained by the two methods were obviously different. We suggest that the difference could be related to factors such as tissue microstructure, the frequency range, sample size and the rheological model employed. For future work we propose some improvements in the comparative tests between SDUV and DMA, such as enlarging the harmonic frequency range of the shear wave to highlight the role of viscosity, finding an appropriate rheological model to improve the accuracy of tissue viscoelasticity estimations.
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Affiliation(s)
- Ying Zhu
- National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518160, China
| | - Xinyu Zhang
- National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518160, China
| | - Yi Zheng
- Department of Electrical and Computer Engineering, St. Cloud State University, St. Cloud, MN 56301, USA
| | - Xin Chen
- National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518160, China
| | - Yuanyuan Shen
- National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518160, China
| | - Haoming Lin
- National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518160, China
| | - Yanrong Guo
- National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518160, China
| | - Tianfu Wang
- National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518160, China
| | - Siping Chen
- National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518160, China.
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297
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Bismuth C, Gerin C, Viguier E, Fau D, Dupasquier F, Cavetier L, David L, Carozzo C. The biomechanical properties of canine skin measured in situ by uniaxial extension. J Biomech 2014; 47:1067-73. [PMID: 24462381 DOI: 10.1016/j.jbiomech.2013.12.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 12/17/2013] [Accepted: 12/22/2013] [Indexed: 11/28/2022]
Abstract
INTRODUCTION A uniaxial extension system was setup to analyze the mechanical properties of dog skin. MATERIAL AND METHODS Pads were glued onto dog skin with constant reproducible geometrical parameters and the extension force was measured as a function of the extension values. Forty-one sites (82 cycling tests) were investigated in situ on 11 canine cadavers, half of them after surgically isolating the test area from the surrounding skin. Series of loading-unloading cycles of up to 5N or 10N or both loads were performed on each site. The elastic properties and the dissipative effects were characterized respectively by evaluating the secant Rigidity at maximum loads and the Fraction of dissipated energy. RESULTS A hysteresis phenomenon, implying the need for preconditioning to attain equilibrium cycles, was apparent during mechanical characterization. Polynomial expressions were used to relate the measured Rigidities and the Fractions of dissipated energy with or without sample isolation. The latter were less affected by isolation. The ratios between the Rigidities at 5N to those at 10N displayed non-linearity in the investigated extension range in contrary to the Fractions of dissipated energy. DISCUSSION/CONCLUSION The parameters confirming the dissipative non-linear elastic behavior of dog skin were identified and the correlation between Rigidity and Fraction of dissipated energy on isolated and non-isolated skin samples was quantitatively determined. This extension setup can now be used as a "true in vivo" mapping tool to determine the mechanical characteristics of the skin during healing processes or during the study of Human skin disease with the dog as an animal model.
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Affiliation(s)
- Camille Bismuth
- CHEVAC, Small Animal Department, VetAgro Sup, Campus vétérinaire de Lyon, University of Lyon, F-69280 Marcy l'Etoile, France. UPSP 2011.03.101 ICE, VetAgro Sup, Université de Lyon, 69280 Marcy L'Etoile, France.
| | - Clothilde Gerin
- CHEVAC, Small Animal Department, VetAgro Sup, Campus vétérinaire de Lyon, University of Lyon, F-69280 Marcy l'Etoile, France. UPSP 2011.03.101 ICE, VetAgro Sup, Université de Lyon, 69280 Marcy L'Etoile, France
| | - Eric Viguier
- CHEVAC, Small Animal Department, VetAgro Sup, Campus vétérinaire de Lyon, University of Lyon, F-69280 Marcy l'Etoile, France. UPSP 2011.03.101 ICE, VetAgro Sup, Université de Lyon, 69280 Marcy L'Etoile, France
| | - Didier Fau
- CHEVAC, Small Animal Department, VetAgro Sup, Campus vétérinaire de Lyon, University of Lyon, F-69280 Marcy l'Etoile, France. UPSP 2011.03.101 ICE, VetAgro Sup, Université de Lyon, 69280 Marcy L'Etoile, France
| | - Florence Dupasquier
- Université de Lyon, Université Claude Bernard Lyon 1, Laboratoire Ingénierie des Matériaux Polymères (IMP@Lyon1), CNRS UMR 5223, Bât. Polytech Lyon, 15 bd Latarjet 69622, Villeurbanne Cedex, France
| | - Laurent Cavetier
- Université de Lyon, Université Claude Bernard Lyon 1, Laboratoire Ingénierie des Matériaux Polymères (IMP@Lyon1), CNRS UMR 5223, Bât. Polytech Lyon, 15 bd Latarjet 69622, Villeurbanne Cedex, France
| | - Laurent David
- Université de Lyon, Université Claude Bernard Lyon 1, Laboratoire Ingénierie des Matériaux Polymères (IMP@Lyon1), CNRS UMR 5223, Bât. Polytech Lyon, 15 bd Latarjet 69622, Villeurbanne Cedex, France
| | - Claude Carozzo
- CHEVAC, Small Animal Department, VetAgro Sup, Campus vétérinaire de Lyon, University of Lyon, F-69280 Marcy l'Etoile, France. UPSP 2011.03.101 ICE, VetAgro Sup, Université de Lyon, 69280 Marcy L'Etoile, France
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298
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Karimi A, Navidbakhsh M. Material properties in unconfined compression of gelatin hydrogel for skin tissue engineering applications. ACTA ACUST UNITED AC 2014; 59:479-86. [DOI: 10.1515/bmt-2014-0028] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/12/2014] [Indexed: 12/30/2022]
Abstract
AbstractGelatin (Gel) has been reported as a promising candidate in tissue engineering owing to its easy availability, biocompatibility, and biodegradability. Gel hydrogel is of potential to be cross-linked with different materials to enhance their biocompatibility for cell culture for tissue engineering applications. The mechanical properties of this versatile material, however, have not been thoroughly determined. In this study, the linear elastic (Young’s modulus and maximum stress) and non-linear hyperelastic (hyperelastic coefficients) mechanical properties of prepared hydrogels at different contents of Gel (wt%) were measured, and its Young’s modulus was compared with that of skin tissue. The prepared cylindrical Gel hydrogels were subjected to a series of unconfined compression tests. The hyperelastic strain energy density function was calibrated using the compressive experimental data. The potential ability of the Yeoh hyperelastic constitutive equation, which has been proposed as the best material model to represent the non-linear behavior of hydrogels, was verified using finite element (FE) simulations. The results revealed that the Young’s modulus and maximum stress of hydrogels are increased by the addition of Gel. The highest Young’s modulus (81 kPa) and maximum stress (24 kPa) were observed for hydrogels with 15 wt% Gel. Results also showed that the hydrogels with a relatively lower content (<7.5 wt%) of Gel have suitable Young’s modulus compared with those with a higher content (>7.5 wt%) for skin tissue engineering. The Yeoh material model was closely fitted with the experimental data and could be used in further biomechanical simulations of the hydrogels. The experimental results were also compared well with those predicted by the FE models. The results of this study might have implications not only for the understanding of the mechanical properties of Gel hydrogel but also for the fabrication of polymeric substrate materials suitable for skin tissue engineering applications.
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299
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Santos JCC, Mansur AAP, Ciminelli VST, Mansur HS. Nanocomposites of Poly(Vinyl Alcohol)/Functionalized-Multiwall Carbon Nanotubes Conjugated With Glucose Oxidase for Potential Application as Scaffolds in Skin Wound Healing. INT J POLYM MATER PO 2013. [DOI: 10.1080/00914037.2013.812090] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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300
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Pailler-Mattei C, Debret R, Vargiolu R, Sommer P, Zahouani H. In vivo skin biophysical behaviour and surface topography as a function of ageing. J Mech Behav Biomed Mater 2013; 28:474-83. [DOI: 10.1016/j.jmbbm.2013.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 03/19/2013] [Accepted: 04/09/2013] [Indexed: 12/22/2022]
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