title: Ultrasound Elastography for Estimation of Regional Strain of Multilayered Hydrogels and Tissue-Engineered Cartilage.
abstract: Tissue-engineered (TE) cartilage constructs tend to develop inhomogeneously, thus, to predict the mechanical performance of the tissue, conventional biomechanical testing, which yields average material properties, is of limited value. Rather, techniques for evaluating regional and depth-dependent properties of TE cartilage, preferably non-destructively, are required. The purpose of this study was to build upon our previous results and to investigate the feasibility of using ultrasound elastography to non-destructively assess the depth-dependent biomechanical characteristics of TE cartilage while in a sterile bioreactor. As a proof-of-concept, and to standardize an assessment protocol, a well-characterized three-layered hydrogel construct was used as a surrogate for TE cartilage, and was studied under controlled incremental compressions. The strain field of the construct predicted by elastography was then validated by comparison with a poroelastic finite-element analysis (FEA). On average, the differences between the strains predicted by elastography and the FEA were within 10%. Subsequently engineered cartilage tissue was evaluated in the same test fixture. Results from these examinations showed internal regions where the local strain was 1-2 orders of magnitude greater than that near the surface. These studies document the feasibility of using ultrasound to evaluate the mechanical behaviors of maturing TE constructs in a sterile environment.
authors.affiliation: Department of Mechanical and Aerospace Engineering, Case Western Reserve University, 2123 Martin Luther King Jr. Drive, Glennan Building Room 616A, Cleveland, OH, 44106, USA.|Department of Mechanical Engineering, National Central University, Taoyuan, Taiwan.
authors.forename: Chen-Yuan
authors.initials: CY
authors.lastname: Chung
authors.affiliation: Department of Mechanical and Aerospace Engineering, Case Western Reserve University, 2123 Martin Luther King Jr. Drive, Glennan Building Room 616A, Cleveland, OH, 44106, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Heebner
authors.affiliation: Department of Chemical and Biomolecular Engineering, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: Harihara
authors.initials: H
authors.lastname: Baskaran
authors.affiliation: Department of Biology (Skeletal Research Center), Case Western Reserve University, Cleveland, OH, USA.
authors.forename: Jean F
authors.initials: JF
authors.lastname: Welter
authors.affiliation: Department of Mechanical and Aerospace Engineering, Case Western Reserve University, 2123 Martin Luther King Jr. Drive, Glennan Building Room 616A, Cleveland, OH, 44106, USA. jmm12@case.edu.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Mansour
mesh_terms: D019149:Bioreactors; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002478:Cells, Cultured; D054459:Elasticity Imaging Techniques; D020342:Finite Element Analysis; D006801:Humans; D020100:Hydrogels; D059630:Mesenchymal Stem Cells; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D023822:Tissue Engineering
chemical_list: D020100:Hydrogels
keywords: Acoustic methods; Bioreactor; Depth-dependent deformation; Mechanical properties; Multimodal evaluation