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Chittajallu SNSH, Gururani H, Tse KM, Rath SN, Basu S, Chinthapenta V. Investigation of microstructural failure in the human cornea through fracture tests. Sci Rep 2023; 13:13876. [PMID: 37620375 PMCID: PMC10449857 DOI: 10.1038/s41598-023-40286-3] [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: 03/23/2023] [Accepted: 08/08/2023] [Indexed: 08/26/2023] Open
Abstract
Fracture toughness of the human cornea is one of the critical parameters in suture-involved corneal surgeries and the development of bioengineered mimetics of the human cornea. The present article systematically studied the fracture characteristics of the human cornea to evaluate its resistance to tear in the opening (Mode-I) and trouser tear mode (Mode-III). Tear experiments reveal the dependency of the fracture behavior on the notch size and its location created in the corneal specimens. The findings indicate lamellar tear and collagen fiber pull-out as a failure mechanism in trouser tear and opening mode tests, respectively. Experimental results have shown a localized variation of tear behavior in trouser tear mode and indicated an increasing resistance to tear from the corneal center to the periphery. This article demonstrated the complications of evaluating fracture toughness in opening mode and showed that the limbus was weaker than the cornea and sclera against tearing. The overall outcomes of the present study help in designing experiments to understand the toughness of the diseased tissues, understanding the effect of the suturing location and donor placement, and creating numerical models to study parameters affecting corneal replacement surgery.
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Affiliation(s)
- Sai Naga Sri Harsha Chittajallu
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad (IIT Hyderabad), Hyderabad, India
- Department of Mechanical and Product Design Engineering, Swinburne University of Technology, Melbourne, Australia
- Centre for Technology Innovation, LV Prasad Eye Institute, Hyderabad, India
| | - Himanshu Gururani
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad (IIT Hyderabad), Hyderabad, India
| | - Kwong Ming Tse
- Department of Mechanical and Product Design Engineering, Swinburne University of Technology, Melbourne, Australia
| | - Subha Narayan Rath
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Hyderabad, India
| | - Sayan Basu
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, India
| | - Viswanath Chinthapenta
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad (IIT Hyderabad), Hyderabad, India.
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Truong N, Menon R, Richardson L. The Role of Fetal Membranes during Gestation, at Term, and Preterm Labor. PLACENTA AND REPRODUCTIVE MEDICINE 2023; 2:4. [PMID: 38304894 PMCID: PMC10831903 DOI: 10.54844/prm.2022.0296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
During pregnancy, the fetal membranes (i.e., amniochorionic membranes) surround the intrauterine cavity and provide mechanical, immune, and endocrine support to protect the fetus. Though they are a vital component of the intrauterine cavity, the fetal membranes are largely overlooked as an extension of the placenta, leading to a poor understanding of their role during gestation, parturition, or preterm birth. The fetal membranes are comprised of fetal cellular and stromal layers and line up with maternal decidua forming the feto-maternal interface during pregnancy. This interface plays a large role during pregnancy and the induction of term or preterm parturition (e.g., labor). Here we summarize the function of the fetal membranes focusing on their role during gestation at term, and during preterm births.
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Affiliation(s)
- Nina Truong
- The University of Texas Medical Branch John Sealy School of Medicine at Galveston, Galveston, TX, USA
| | - Ramkumar Menon
- Department of Obstetrics & Gynecology, Division of Basic Science and Translational Research, The University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Lauren Richardson
- Department of Obstetrics & Gynecology, Division of Basic Science and Translational Research, The University of Texas Medical Branch at Galveston, Galveston, TX, USA
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Peng L, Liang Y, Yue J, Li H, Deng A, Xie S, Tang XZ, Wang J, Mao Z. Dramatic improvement in the mechanical properties of polydopamine/polyacrylamide hydrogel mediated human amniotic membrane. RSC Adv 2023; 13:3635-3642. [PMID: 36756590 PMCID: PMC9875367 DOI: 10.1039/d2ra07622e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/17/2023] [Indexed: 01/27/2023] Open
Abstract
Human amniotic membrane (hAM) is a promising material for tissue engineering due to several benefits, including desirable biocompatibility, stem cell source, antibacterial activity, etc. However, because of its low elasticity, the clinical application of hAM is severely restricted. To solve this issue, we employed polydopamine/polyacrylamide (PDA/PAM) hydrogels to toughen hAM. The test results indicated that the PDA/PAM hydrogel can enhance the toughness of hAM dramatically due to the formation of abundant chemical bonds and the strong mechanical properties of the hydrogel itself. Compared to pure hAM, the break elongation and tensile strength of PDA/PAM-toughened hAM rose by 154.15 and 492.31%, respectively. And most importantly, the fracture toughness was almost 15 times higher than untreated hAM. In addition, the cytotoxicity of the PDA/PAM-coated hAM was not detected due to the superior biocompatibility of the chemicals used in the study. Treating hAM with adhesive hydrogels to increase its mechanical characteristics will further promote the application of hAM as a tissue engineering material.
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Affiliation(s)
- Lin Peng
- Changsha Hospital for Maternal and Child Health Care Affiliated to Hunan Normal University Changsha 410083 China
| | - Yufei Liang
- Powder Metallurgy Research Institute, Central South UniversityChangsha410083China
| | - Jianling Yue
- Powder Metallurgy Research Institute, Central South UniversityChangsha410083China
| | - Hanmei Li
- Changsha Hospital for Maternal and Child Health Care Affiliated to Hunan Normal University Changsha 410083 China
| | - Aimin Deng
- Changsha Hospital for Maternal and Child Health Care Affiliated to Hunan Normal University Changsha 410083 China
| | - Shun Xie
- Changsha Hospital for Maternal and Child Health Care Affiliated to Hunan Normal University Changsha 410083 China
| | - Xiu-Zhi Tang
- Research Institute of Aerospace Technology, Central South UniversityChangsha410083China
| | - Jing Wang
- Department of Pathology, Xiangya Hospital, Central South University Changsha 410083 China
| | - Zenghui Mao
- Changsha Hospital for Maternal and Child Health Care Affiliated to Hunan Normal University Changsha 410083 China
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Toaquiza Tubon JD, Moreno-Flores O, Sree VD, Tepole AB. Anisotropic damage model for collagenous tissues and its application to model fracture and needle insertion mechanics. Biomech Model Mechanobiol 2022; 21:1-16. [PMID: 36057750 DOI: 10.1007/s10237-022-01624-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 08/02/2022] [Indexed: 11/30/2022]
Abstract
The analysis of tissue mechanics in biomedical applications demands nonlinear constitutive models able to capture the energy dissipation mechanisms, such as damage, that occur during tissue deformation. Furthermore, implementation of sophisticated material models in finite element models is essential to improve medical devices and diagnostic tools. Building on previous work toward microstructure-driven models of collagenous tissue, here we show a constitutive model based on fiber orientation and waviness distributions for skin that captures not only the anisotropic strain-stiffening response of this and other collagen-based tissues, but, additionally, accounts for tissue damage directly as a function of changes in the microstructure, in particular changes in the fiber waviness distribution. The implementation of this nonlinear constitutive model as a user subroutine in the popular finite element package Abaqus enables large-scale finite element simulations for biomedical applications. We showcase the performance of the model in fracture simulations during pure shear tests, as well as simulations of needle insertion into skin relevant to auto-injector design.
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Affiliation(s)
| | - Omar Moreno-Flores
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Vivek D Sree
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Adrian B Tepole
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA. .,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
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Computational modeling in pregnancy biomechanics research. J Mech Behav Biomed Mater 2022; 128:105099. [DOI: 10.1016/j.jmbbm.2022.105099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 01/11/2022] [Accepted: 01/18/2022] [Indexed: 11/24/2022]
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Characterization of Cryopreserved Canine Amniotic Membrane. MEMBRANES 2021; 11:membranes11110824. [PMID: 34832052 PMCID: PMC8624976 DOI: 10.3390/membranes11110824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/23/2021] [Accepted: 10/25/2021] [Indexed: 12/12/2022]
Abstract
Amniotic membrane is an effective corneal reconstruction material in veterinary surgery. Cryopreserved amniotic membrane is widely used in practice. Properties of cryopreserved canine amniotic membranes are currently not well studied. This study aimed to compare three properties between canine amniotic membranes cryopreserved for 7 days and 30 days, including tensile strength, transparency, and cell viability. After their respective cryopreservation time, stress-strain curves of the cryopreserved membranes' tensile strength were assessed using a universal testing machine. Both groups produced J-shaped stress-strain curves with statistically comparable parameters, including maximum stress, strain, and Young's modulus. The percentage of cell viability was observed by trypan blue staining under a light microscope. Membrane transparency was tested with a spectrophotometer. Transparency tests showed high levels of light transmission and low haze, with no statistical difference between groups. Cell viability was statistically lower in the 30-day cryopreserved group. Tensile strength and transparency of cryopreserved CAM were not significantly impeded for up to 30 days. For CAM to be used as an alternative corneal transplant material in veterinary and regenerative medicine, further research on cell biology, biomechanical properties of the membrane, and cell viability should be conducted.
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Miller KS, Myers K, Oyen M. Bioengineering in women's health, volume 2: pregnancy—from implantation to parturition. Interface Focus 2019. [DOI: 10.1098/rsfs.2019.0081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
This special issue of
Interface Focus
is the second of two sets of articles on the topic of bioengineering in women's health. This second issue in the series focuses on pregnancy, a dynamic time in a women's life that involves dramatic physiologic changes within a relatively small timeframe. Pregnancy demands endurance and resilience of one's body and represents a critical component of women's health research. The health of an individual leading up to, during and after pregnancy is paramount for reproductive health and the lifelong health of offspring. The articles in this issue explore physiological events that support reproduction spanning from embryo implantation, through gestation, to delivery and parturition. Specifically, the articles highlight essential developments in placenta, fetal membranes, cervix, pelvic floor and anthropometry research. The featured bioengineering disciplines deployed to study such complex biological processes are diverse, with articles detailing the latest advancements in computational modelling at various biological length-scales, biomaterial design, material modelling, non-invasive diagnostic techniques, microfluidic devices and experimental mechanics. This second issue continues the first in this series, on the physiology of the non-pregnant woman.
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Affiliation(s)
- Kristin S. Miller
- Biomedical Engineering, Tulane University, 500 Lindy Boggs Center, New Orleans, LA 70118, USA
| | - Kristin Myers
- Mechanical Engineering, Columbia University, New York, NY 10025, USA
| | - Michelle Oyen
- Department of Engineering, East Carolina University, Greenville, NC, USA
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