1
|
Böl M, Leichsenring K, Kohn S, Ehret AE. The anisotropic and region-dependent mechanical response of wrap-around tendons under tensile, compressive and combined multiaxial loads. Acta Biomater 2024; 183:157-172. [PMID: 38838908 DOI: 10.1016/j.actbio.2024.05.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 05/20/2024] [Accepted: 05/30/2024] [Indexed: 06/07/2024]
Abstract
The present work reports on the multiaxial region and orientation-dependent mechanical properties of two porcine wrap-around tendons under tensile, compressive and combined loads based on an extensive study with n=175 samples. The results provide a detailed dataset of the anisotropic tensile and compressive longitudinal properties and document a pronounced tension-compression asymmetry. Motivated by the physiological loading conditions of these tendons, which include transversal compression at bony abutments in addition to longitudinal tension, we systematically investigated the change in axial tension when the tendon is compressed transversally along one or both perpendicular directions. The results reveal that the transversal compression can increase axial tension (proximal-distal direction) in both cases to orders of 30%, yet by a larger amount in the first case (transversal compression in anterior-posterior direction), which seems to be more relevant for wrap-around tendons in-vivo. These quantitative measurements are in line with earlier findings on auxetic properties of tendon tissue, but show for the first time the influence of this property on the stress response of the tendon, and may thus reveal an important functional principle within these essential elements of force transmission in the body. STATEMENT OF SIGNIFICANCE: The work reports for the first time on multiaxial region and orientation-dependent mechanical properties of wrap-around tendons under various loads. The results indicate that differences in the mechanical properties exist between zones that are predominantly in a uniaxial tensile state and those that experience complex load states. The observed counterintuitive increase of the axial tension upon lateral compression points at auxetic properties of the tendon tissue which may be pivotal for the function of the tendon as an element of the musculoskeletal system. It suggests that the tendon's performance in transmitting forces is not diminished but enhanced when the action line is deflected by a bony pulley around which the tendon wraps, representing an important functional principle of tendon tissue.
Collapse
Affiliation(s)
- Markus Böl
- Institute of Mechanics and Adaptronics, Technische Universität Braunschweig, Braunschweig D-38106, Germany.
| | - Kay Leichsenring
- Institute of Mechanics and Adaptronics, Technische Universität Braunschweig, Braunschweig D-38106, Germany
| | - Stephan Kohn
- Institute of Mechanics and Adaptronics, Technische Universität Braunschweig, Braunschweig D-38106, Germany
| | - Alexander E Ehret
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland; Institute for Mechanical Systems, ETH Zurich, Zürich, CH-8092, Switzerland
| |
Collapse
|
2
|
Stokolosa AM, Thomas-Colwell J, Dilley KK, Qu Y, Cullip C, Heidari AE, Huang M, Kerrigan N, Hsu K, Leonard J, Prasad KR, Wong BJ, Hill MG. Electromechanical Cornea Reshaping for Refractive Vision Therapy. ACS Biomater Sci Eng 2023; 9:595-600. [PMID: 36634100 PMCID: PMC9930080 DOI: 10.1021/acsbiomaterials.2c01177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The corneal stroma consists of orthogonally stacked collagen-fibril lamellae that determine the shape of the cornea and provide most of the refractive power of the eye. We have applied electromechanical reshaping (EMR), an electrochemical platform for remodeling cartilage and other semirigid tissues, to change the curvature of the cornea as a potential procedure for nonsurgical vision correction. EMR relies on short electrochemical pulses to electrolyze water, with subsequent diffusion of protons into the extracellular matrix of collagenous tissues; protonation of immobilized anions within this matrix disrupts the ionic-bonding network, leaving the tissue transiently responsive to mechanical remodeling. Re-equilibration to physiological pH restores the ionic matrix, resulting in persistent shape change of the tissue. Using ex vivo rabbit eyes, we demonstrate here the controlled change of corneal curvature over a wide range of refractive powers with no loss of optical transparency. Optical coherence tomography (OCT), combined with second-harmonic generation (SHG) and confocal microscopy, establish that EMR enables extremely fine control of corneal contouring while maintaining the underlying macromolecular collagen structure and stromal cellular viability, positioning electrochemical vision therapy as a potentially simple and ultralow-cost modality for correcting routine refractive errors.
Collapse
Affiliation(s)
- Anna M. Stokolosa
- Department
of Chemistry, Occidental College, Los Angeles, California 90041, United States
| | - Jack Thomas-Colwell
- Department
of Chemistry, Occidental College, Los Angeles, California 90041, United States
| | - Katelyn K. Dilley
- Beckman
Laser Institute & Medical Clinic, University
of California, Irvine, Irvine, California 92697, United States
| | - Yueqiao Qu
- Beckman
Laser Institute & Medical Clinic, University
of California, Irvine, Irvine, California 92697, United States,Department
of Biomedical Engineering, University of
California, Irvine, Irvine, California 92697, United States
| | - Charlotte Cullip
- Department
of Chemistry, Occidental College, Los Angeles, California 90041, United States
| | - Andrew E. Heidari
- Beckman
Laser Institute & Medical Clinic, University
of California, Irvine, Irvine, California 92697, United States,Department
of Biomedical Engineering, University of
California, Irvine, Irvine, California 92697, United States
| | - Michelle Huang
- Department
of Chemistry, Occidental College, Los Angeles, California 90041, United States
| | - Nathalie Kerrigan
- Department
of Chemistry, Occidental College, Los Angeles, California 90041, United States
| | - Kellie Hsu
- Department
of Chemistry, Occidental College, Los Angeles, California 90041, United States
| | - Jack Leonard
- Department
of Chemistry, Occidental College, Los Angeles, California 90041, United States
| | | | - Brian J.F. Wong
- Beckman
Laser Institute & Medical Clinic, University
of California, Irvine, Irvine, California 92697, United States,Department
of Biomedical Engineering, University of
California, Irvine, Irvine, California 92697, United States,Department
of Otolaryngology-Head and Neck Surgery, School of Medicine, University of California, Irvine, Orange, California 92617, United States,
| | - Michael G. Hill
- Department
of Chemistry, Occidental College, Los Angeles, California 90041, United States,
| |
Collapse
|
3
|
Park AC, Chan CK, Hutchison DM, Patel U, Hong EM, Steward E, Dilley KK, Sterritt NL, Kim S, Hill MG, You JS, Wong BJF. In vivo electrochemical lipolysis of fat in a Yucatan pig model: A proof of concept study. Lasers Surg Med 2023; 55:135-145. [PMID: 36511512 DOI: 10.1002/lsm.23620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/01/2022] [Accepted: 11/26/2022] [Indexed: 12/15/2022]
Abstract
OBJECTIVES Traditional fat contouring is now regularly performed using numerous office- based less invasive techniques. However, some limitations of these minimally invasive techniques include high cost or limited selectivity with performing localized contouring and reduction of fat. These shortcomings may potentially be addressed by electrochemical lipolysis (ECLL), a novel approach that involves the insertion of electrodes into tissue followed by application of a direct current (DC) electrical potential. This results in the hydrolysis of tissue water creating active species that lead to fat necrosis and apoptosis. ECLL can be accomplished using a simple voltage-driven system (V-ECLL) or a potential-driven feedback cell (P-ECLL) both leading to water electrolysis and the creation of acid and base in situ. The aim of this study is to determine the long-lasting effects of targeted ECLL in a Yucatan pig model. METHODS A 5-year-old Yucatan pig was treated with both V-ECLL and P-ECLL in the subcutaneous fat layer using 80:20 platinum:iridium needle electrodes along an 8 cm length. Dosimetry parameters included 5 V V-ECLL for 5, 10, and 20 minutes, and -1.5 V P-ECLL, -2.5 V P-ECLL, -3.5 V P-ECLL for 5 minutes. The pig was assessed for changes in fat reduction over 3 months with digital photography and ultrasound. After euthanasia, tissue sections were harvested and gross pathology and histology were examined. RESULTS V-ECLL and P-ECLL treatments led to visible fat reduction (12.1%-27.7% and 9.4%-40.8%, respectively) and contour changes across several parameters. An increased reduction of the superficial fat layer occurred with increased dosimetry parameters with an average charge transfer of 12.5, 24.3, and 47.5 C transferred for 5 V V-ECLL for 5, 10, and 20 minutes, respectively, and 2.0, 11.5, and 24.0 C for -1.5 V P-ECLL, -2.5 V P-ECLL, -3.5 V P-ECLL for 5 minutes, respectively. These dose-dependent changes were also evidenced by digital photography, gross pathology, ultrasound imaging, and histology. CONCLUSIONS ECLL results in selective damage and long-lasting changes to the adipose layer in vivo. These changes are dose-dependent, thus allowing for more precise contouring of target areas. P-ECLL has greater efficiency and control of total charge transfer compared to V-ECLL, suggesting that a low-voltage potentiostat treatment can result in fat apoptosis equivalent to a high-voltage DC system.
Collapse
Affiliation(s)
- Asher C Park
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, California, USA
| | - Carmen K Chan
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of California-Irvine, Orange, California, USA
| | - Dana M Hutchison
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, California, USA
| | - Urja Patel
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, California, USA
| | - Ellen M Hong
- School of Medicine, Hackensack Meridian, Nutley, New Jersey, USA
| | - Earl Steward
- Department of Surgery, School of Medicine, University of California-Irvine, Orange, California, USA
| | - Katelyn K Dilley
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, California, USA
| | - Naya L Sterritt
- Department of Biomedical Engineering, University of California-Irvine, Irvine, California, USA
| | - Sehwan Kim
- Department of Biomedical Engineering, Beckman Laser Institute, Korea, Dankook University, Cheonan-si, Chungnam, Republic of Korea
| | - Michael G Hill
- Department of Chemistry, Occidental College, Los Angeles, California, USA
| | - Joon S You
- eLysis Inc., Laguna Niguel, California, USA
| | - Brian J F Wong
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, California, USA.,Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of California-Irvine, Orange, California, USA.,Department of Biomedical Engineering, University of California-Irvine, Irvine, California, USA
| |
Collapse
|
4
|
Kalemba M, Ekiert-Radecka M, Wajdzik M, Mlyniec A. An in-House System for the Precise Measurement of Electrical Potentials and Mechanical Properties of Soft Tissues: Design and Validation Using Adult Mammalian Tendon Fascicle Bundles. MATERIALS 2022; 15:ma15134444. [PMID: 35806569 PMCID: PMC9267749 DOI: 10.3390/ma15134444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 06/03/2022] [Accepted: 06/17/2022] [Indexed: 02/04/2023]
Abstract
Tissues, such as skin, bones, and tendons, exhibit a piezoelectric effect, which may be an important phenomenon in terms of tissue renewal and regeneration as well as the possibility of modifying their mechanical behavior. In this article, we present the design and development of an in-house system for the precise measurement of electrical potentials and mechanical properties of tendons. The system was validated using tendon fascicle bundles derived from positional as well as energy-storing tendons from various adult mammals (porcine, bovine, and deer samples). The presented system is able to capture changes in elastic and viscoelastic properties of tissue as well as its time–voltage response and, thus, may be used in a broad spectrum of future studies to uncover factors influencing piezoelectric phenomena in tendons. This, in turn, will help to optimize current methods used in physiotherapy and postoperative treatment for effective tendon recovery.
Collapse
Affiliation(s)
- Marek Kalemba
- Faculty of Mechanical Engineering and Robotics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow, Poland; (M.K.); (M.E.-R.)
| | - Martyna Ekiert-Radecka
- Faculty of Mechanical Engineering and Robotics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow, Poland; (M.K.); (M.E.-R.)
| | - Marek Wajdzik
- Faculty of Forestry, University of Agriculture, Al. 29-listopada 46, 31-425 Krakow, Poland;
| | - Andrzej Mlyniec
- Faculty of Mechanical Engineering and Robotics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow, Poland; (M.K.); (M.E.-R.)
- Correspondence:
| |
Collapse
|
5
|
Dilley KK, Borden PA, Qu Y, Heidari AE, Prasad KR, Li Y, Sun CH, Chen Z, Kim S, Hill MG, Wong BJF. Potential-Driven Electrochemical Clearing of Ex Vivo Alkaline Corneal Injuries. Transl Vis Sci Technol 2022; 11:32. [PMID: 35061010 PMCID: PMC8787648 DOI: 10.1167/tvst.11.1.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Purpose Corneal chemical injuries (CCI) obscure vision by opacifying the cornea; however, current treatments may not fully restore clarity. Here, we investigated potential-driven electrochemical treatment (P-ECT) to restore clarity after alkaline-based CCI in ex vivo rabbit corneas and examined collagen fiber orientation changes using second harmonic generation (SHG). Methods NaOH was applied to the corneas of intact New Zealand white rabbit globes. P-ECT was performed on the opacified cornea while optical coherence tomography (OCT) imaging (∼35 frames per second) was simultaneously performed. SHG imaging evaluated collagen fiber structure before NaOH application and after P-ECT. Irrigation with water served as a control. Results P-ECT restored local optical clarity after NaOH exposure. OCT imaging shows both progression of NaOH injury and the restoration of clarity in real time. Analysis of SHG z-stack images show that collagen fibril orientation is similar between control, NaOH-damaged, and post-P-ECT corneas. NaOH-injured corneas flushed with water (15 minutes) show no restoration of clarity. Conclusions P-ECT may be a means to correct alkaline CCI. Collagen fibril orientation does not change after NaOH exposure or P-ECT, suggesting that no irreversible matrix level fiber changes occur. Further studies are required to determine the mechanism for corneal clearing and to ascertain the optimal electrical dosimetry parameters and electrode designs. Translational Relevance Our findings suggest that P-ECT is a potentially effective, low-cost treatment for alkaline CCI.
Collapse
Affiliation(s)
- Katelyn K Dilley
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, CA, USA.,Department of Biomedical Engineering, University of California-Irvine, Irvine, CA, USA
| | - Pamela A Borden
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, CA, USA.,Department of Biomedical Engineering, University of California-Irvine, Irvine, CA, USA
| | - Yueqiao Qu
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, CA, USA.,Department of Biomedical Engineering, University of California-Irvine, Irvine, CA, USA
| | - Andrew E Heidari
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, CA, USA.,Department of Biomedical Engineering, University of California-Irvine, Irvine, CA, USA
| | - Karthik R Prasad
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, CA, USA.,School of Medicine, University of California-Irvine, Irvine, CA, USA
| | - Yan Li
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, CA, USA.,Department of Biomedical Engineering, University of California-Irvine, Irvine, CA, USA
| | - Chung Ho Sun
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, CA, USA
| | - Zhongping Chen
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, CA, USA.,Department of Biomedical Engineering, University of California-Irvine, Irvine, CA, USA
| | - Sehwan Kim
- Beckman Laser Institute-Korea, Department of Biomedical Engineering, Dankook University, Cheonan-si, Chungnam, Republic of Korea
| | - Michael G Hill
- Department of Chemistry, Occidental College, Los Angeles, CA, USA
| | - Brian J F Wong
- Beckman Laser Institute & Medical Clinic, University of California-Irvine, Irvine, CA, USA.,Department of Biomedical Engineering, University of California-Irvine, Irvine, CA, USA.,Department of Otolaryngology-Head and Neck Surgery, University of California-Irvine, School of Medicine, Orange, CA, USA
| |
Collapse
|
6
|
Mlyniec A, Dabrowska S, Heljak M, Weglarz WP, Wojcik K, Ekiert-Radecka M, Obuchowicz R, Swieszkowski W. The dispersion of viscoelastic properties of fascicle bundles within the tendon results from the presence of interfascicular matrix and flow of body fluids. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 130:112435. [PMID: 34702520 DOI: 10.1016/j.msec.2021.112435] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 09/06/2021] [Accepted: 09/09/2021] [Indexed: 01/12/2023]
Abstract
In this work, we investigate differences in the mechanical and structural properties of tendon fascicle bundles dissected from different areas of bovine tendons. The properties of tendon fascicle bundles were investigated by means of uniaxial tests with relaxation periods and hysteresis, dynamic mechanical analysis (DMA), as well as magnetic resonance imaging (MRI). Uniaxial tests with relaxation periods revealed greater elastic modulus, hysteresis, as well as stress drop during the relaxation of samples dissected from the posterior side of the tendon. However, the normalized stress relaxation curves did not show a statistically significant difference in the stress drop between specimens cut from different zones or between different strain levels. Using dynamic mechanical analysis, we found that fascicle bundles dissected from the anterior side of the tendon had lower storage and loss moduli, which could result from altered fluid flow within the interfascicular matrix (IFM). The lower water content, diffusivity, and higher fractional anisotropy of the posterior part of the tendon, as observed using MRI, indicates a different structure of the IFM, which controls the flow of fluids within the tendon. Our results show that the viscoelastic response to dynamic loading is correlated with fluid flow within the IFM, which was confirmed during analysis of the MRI results. In contrast to this, the long-term relaxation of tendon fascicle bundles is controlled by viscoplasticity of the IFM and depends on the spatial distribution of the matrix within the tendon. Comparison of results from tensile tests, DMA, and MRI gives new insight into tendon mechanics and the role of the IFM. These findings may be useful in improving the diagnosis of tendon injury and effectiveness of medical treatments for tendinopathies.
Collapse
Affiliation(s)
- Andrzej Mlyniec
- AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Krakow, Poland.
| | - Sylwia Dabrowska
- AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Krakow, Poland
| | - Marcin Heljak
- Warsaw University of Technology, Faculty of Materials Science and Engineering, Warsaw, Poland
| | | | - Kaja Wojcik
- AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Krakow, Poland
| | - Martyna Ekiert-Radecka
- AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, Krakow, Poland
| | - Rafal Obuchowicz
- Jagiellonian University Collegium Medicum, Department of Radiology, Krakow, Poland
| | - Wojciech Swieszkowski
- Warsaw University of Technology, Faculty of Materials Science and Engineering, Warsaw, Poland
| |
Collapse
|