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Zhu H, Miller EY, Lee W, Wilson RL, Neu CP. In vivo human knee varus-valgus loading apparatus for analysis of MRI-based intratissue strain and relaxometry. J Biomech 2024; 171:112171. [PMID: 38861862 DOI: 10.1016/j.jbiomech.2024.112171] [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: 08/31/2023] [Revised: 05/14/2024] [Accepted: 05/23/2024] [Indexed: 06/13/2024]
Abstract
The diagnosis of early-stage osteoarthritis remains as an unmet challenge in medicine and a roadblock to evaluating the efficacy of disease-modifying treatments. Recent studies demonstrate that unique patterns of intratissue cartilage deformation under cyclic loading can serve as potential biomarkers to detect early disease pathogenesis. However, a workflow to obtain deformation, strain maps, and quantitative MRI metrics due to the loading of articular cartilage in vivo has not been fully developed. In this study, we characterize and demonstrate an apparatus that is capable of applying a varus-valgus load to the human knee in vivo within an MRI environment to enable the measurement of cartilage structure and mechanical function. The apparatus was first tested in a lab environment, then the functionality and utility of the apparatus were examined during varus loading in a clinical 3T MRI system for human imaging. We found that the device enables quantitative MRI metrics for biomechanics and relaxometry data acquisition during joint loading leading to compression of the medial knee compartment. Integration with spiral DENSE MRI during cyclic loading provided time-dependent displacement and strain maps within the tibiofemoral cartilage. The results from these procedures demonstrate that the performance of this loading apparatus meets the design criteria and enables a simple and practical workflow for future studies of clinical cohorts, and the identification and validation of imaging-based biomechanical biomarkers.
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Affiliation(s)
- Hongtian Zhu
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, USA
| | - Emily Y Miller
- Biomedical Engineering Program, University of Colorado Boulder, Boulder, CO, USA
| | - Woowon Lee
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, USA
| | - Robert L Wilson
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, USA
| | - Corey P Neu
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, USA; Biomedical Engineering Program, University of Colorado Boulder, Boulder, CO, USA; BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA.
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Miller EY, Lee W, Lowe T, Zhu H, Argote PF, Dresdner D, Kelly J, Frank RM, McCarty E, Bravman J, Stokes D, Emery NC, Neu CP. MRI-derived Articular Cartilage Strains Predict Patient-Reported Outcomes Six Months Post Anterior Cruciate Ligament Reconstruction. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.04.27.24306484. [PMID: 38746083 PMCID: PMC11092718 DOI: 10.1101/2024.04.27.24306484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Key terms Multicontrast and Multiparametric, Magnetic Resonance Imaging, Osteoarthritis, Functional Biomechanical Imaging, Knee Joint Degeneration What is known about the subject: dualMRI has been used to quantify strains in a healthy human population in vivo and in cartilage explant models. Previously, OA severity, as determined by histology, has been positively correlated to increased shear and transverse strains in cartilage explants. What this study adds to existing knowledge: This is the first in vivo use of dualMRI in a participant demographic post-ACL reconstruction and at risk for developing osteoarthritis. This study shows that dualMRI-derived strains are more significantly correlated with patient-reported outcomes than any MRI relaxometry metric. Background Anterior cruciate ligament (ACL) injuries lead to an increased risk of osteoarthritis, characterized by altered cartilage tissue structure and function. Displacements under applied loading by magnetic resonance imaging (dualMRI) is a novel MRI technique that can be used to quantify mechanical strain in cartilage while undergoing a physiological load. Purpose To determine if strains derived by dualMRI and relaxometry measures correlate with patient-reported outcomes at six months post unilateral ACL reconstruction. Study Design Cohort study. Methods Quantitative MRI (T2, T2*, T1ρ) measurements and transverse, axial, and shear strains were quantified in the medial articular tibiofemoral cartilage of 35 participants at six-months post unilateral ACL reconstruction. The relationships between patient-reported outcomes (WOMAC, KOOS, MARS) and all qMRI relaxation times were quantified using general linear mixed-effects models. A combined best-fit multicontrast MRI model was then developed using backwards regression to determine the patient features and MRI metrics that are most predictive of patient-reported outcome scores. Results Higher femoral strains were significantly correlated with worse patient-reported functional outcomes. Femoral shear and transverse strains were positively correlated with six-month KOOS and WOMAC scores, after controlling for covariates. No relaxometry measures were correlated with patient-reported outcome scores. We identified the best-fit model for predicting WOMAC score using multiple MRI measures and patient-specific information, including sex, age, graft type, femoral transverse strain, femoral axial strain, and femoral shear strain. The best-fit model significantly predicted WOMAC score (p<0.001) better than any one individual MRI metric alone. When we regressed the model-predicted WOMAC scores against the patient-reported WOMAC scores, we found that our model achieved a goodness of fit exceeding 0.52. Conclusions This work presents the first use of dualMRI in vivo in a cohort of participants at risk for developing osteoarthritis. Our results indicate that both shear and transverse strains are highly correlated with patient-reported outcome severity could serve as novel imaging biomarkers to predict the development of osteoarthritis.
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Wilson RL, Emery NC, Pierce DM, Neu CP. Spatial Gradients of Quantitative MRI as Biomarkers for Early Detection of Osteoarthritis: Data From Human Explants and the Osteoarthritis Initiative. J Magn Reson Imaging 2023; 58:189-197. [PMID: 36285338 PMCID: PMC10126208 DOI: 10.1002/jmri.28471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Healthy articular cartilage presents structural gradients defined by distinct zonal patterns through the thickness, which may be disrupted in the pathogenesis of several disorders. Analysis of textural patterns using quantitative MRI data may identify structural gradients of healthy or degenerating tissue that correlate with early osteoarthritis (OA). PURPOSE To quantify spatial gradients and patterns in MRI data, and to probe new candidate biomarkers for early severity of OA. STUDY TYPE Retrospective study. SUBJECTS Fourteen volunteers receiving total knee replacement surgery (eight males/two females/four unknown, average age ± standard deviation: 68.1 ± 9.6 years) and 10 patients from the OA Initiative (OAI) with radiographic OA onset (two males/eight females, average age ± standard deviation: 57.7 ± 9.4 years; initial Kellgren-Lawrence [KL] grade: 0; final KL grade: 3 over the 10-year study). FIELD STRENGTH/SEQUENCE 3.0-T and 14.1-T, biomechanics-based displacement-encoded imaging, fast spin echo, multi-slice multi-echo T2 mapping. ASSESSMENT We studied structure and strain in cartilage explants from volunteers receiving total knee replacement, or structure in cartilage of OAI patients with progressive OA. We calculated spatial gradients of quantitative MRI measures (eg, T2) normal to the cartilage surface to enhance zonal variations. We compared gradient values against histologically OA severity, conventional relaxometry, and/or KL grades. STATISTICAL TESTS Multiparametric linear regression for evaluation of the relationship between residuals of the mixed effects models and histologically determined OA severity scoring, with a significance threshold at α = 0.05. RESULTS Gradients of individual relaxometry and biomechanics measures significantly correlated with OA severity, outperforming conventional relaxometry and strain metrics. In human explants, analysis of spatial gradients provided the strongest relationship to OA severity (R2 = 0.627). Spatial gradients of T2 from OAI data identified variations in radiographic (KL Grade 2) OA severity in single subjects, while conventional T2 alone did not. DATA CONCLUSION Spatial gradients of quantitative MRI data may improve the predictive power of noninvasive imaging for early-stage degeneration. EVIDENCE LEVEL 1 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Robert L. Wilson
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, 427 UCB, Boulder, CO 80309
| | - Nancy C. Emery
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant Street, 334 UCB, Boulder, CO 80309
| | - David M. Pierce
- Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, Unit 3139, Storrs, CT 06269
- Department of Biomedical Engineering, University of Connecticut, 260 Glenbrook Road, Unit 3247, Storrs, CT 06269
| | - Corey P. Neu
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, 427 UCB, Boulder, CO 80309
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Ortiz-Arrabal O, Irastorza-Lorenzo A, Campos F, Martín-Piedra MÁ, Carriel V, Garzón I, Ávila-Fernández P, de Frutos MJ, Esteban E, Fernández J, Janer A, Campos A, Chato-Astrain J, Alaminos M. Fibrin and Marine-Derived Agaroses for the Generation of Human Bioartificial Tissues: An Ex Vivo and In Vivo Study. Mar Drugs 2023; 21:md21030187. [PMID: 36976236 PMCID: PMC10058299 DOI: 10.3390/md21030187] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 03/29/2023] Open
Abstract
Development of an ideal biomaterial for clinical use is one of the main objectives of current research in tissue engineering. Marine-origin polysaccharides, in particular agaroses, have been widely explored as scaffolds for tissue engineering. We previously developed a biomaterial based on a combination of agarose with fibrin, that was successfully translated to clinical practice. However, in search of novel biomaterials with improved physical and biological properties, we have now generated new fibrin-agarose (FA) biomaterials using 5 different types of agaroses at 4 different concentrations. First, we evaluated the cytotoxic effects and the biomechanical properties of these biomaterials. Then, each bioartificial tissue was grafted in vivo and histological, histochemical and immunohistochemical analyses were performed after 30 days. Ex vivo evaluation showed high biocompatibility and differences in their biomechanical properties. In vivo, FA tissues were biocompatible at the systemic and local levels, and histological analyses showed that biointegration was associated to a pro-regenerative process with M2-type CD206-positive macrophages. These results confirm the biocompatibility of FA biomaterials and support their clinical use for the generation of human tissues by tissue engineering, with the possibility of selecting specific agarose types and concentrations for applications requiring precise biomechanical properties and in vivo reabsorption times.
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Grants
- FIS PI20/0317 FIS PI20/0318 FIS PI21/0980 ICI19/00024 ICI21/00010 Spanish Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica (I+D+I) of the Spanish Ministry of Science and Innovation (Instituto de Salud Carlos III),
- PE-0395-2019 PI-0442-2019 Consejería de Salud y Familias, Junta de Andalucía, Spain
- IDI-20180052 Hispanagar SA, Burgos, Spain, through CDTI, Ministry of Science and Innovation, Spain, Pro-grama Operativo Plurirregional de Crecimiento Inteligente (CRIN)
- B-CTS-504-UGR20 B-CTS-450-UGR20 marco del Programa Operativo FEDER Andalucía 2014-2020, University of Granada and Conseje-ría de Transformación Económica, Industria, Conocimiento y Universidades
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Affiliation(s)
- Olimpia Ortiz-Arrabal
- Tissue Engineering Group, Department of Histology, University of Granada and Instituto de Investigación Biosanitaria ibs.GRANADA, E18016 Granada, Spain
- Doctoral Program in Biochemistry and Molecular Biology, University of Granada, E18016 Granada, Spain
| | - Ainhoa Irastorza-Lorenzo
- Tissue Engineering Group, Department of Histology, University of Granada and Instituto de Investigación Biosanitaria ibs.GRANADA, E18016 Granada, Spain
| | - Fernando Campos
- Tissue Engineering Group, Department of Histology, University of Granada and Instituto de Investigación Biosanitaria ibs.GRANADA, E18016 Granada, Spain
| | - Miguel Ángel Martín-Piedra
- Tissue Engineering Group, Department of Histology, University of Granada and Instituto de Investigación Biosanitaria ibs.GRANADA, E18016 Granada, Spain
| | - Víctor Carriel
- Tissue Engineering Group, Department of Histology, University of Granada and Instituto de Investigación Biosanitaria ibs.GRANADA, E18016 Granada, Spain
| | - Ingrid Garzón
- Tissue Engineering Group, Department of Histology, University of Granada and Instituto de Investigación Biosanitaria ibs.GRANADA, E18016 Granada, Spain
| | - Paula Ávila-Fernández
- Tissue Engineering Group, Department of Histology, University of Granada and Instituto de Investigación Biosanitaria ibs.GRANADA, E18016 Granada, Spain
| | | | | | | | | | - Antonio Campos
- Tissue Engineering Group, Department of Histology, University of Granada and Instituto de Investigación Biosanitaria ibs.GRANADA, E18016 Granada, Spain
| | - Jesús Chato-Astrain
- Tissue Engineering Group, Department of Histology, University of Granada and Instituto de Investigación Biosanitaria ibs.GRANADA, E18016 Granada, Spain
| | - Miguel Alaminos
- Tissue Engineering Group, Department of Histology, University of Granada and Instituto de Investigación Biosanitaria ibs.GRANADA, E18016 Granada, Spain
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Lee W, Miller EY, Zhu H, Luetkemeyer CM, Schneider SE, Neu CP. High frame rate deformation analysis of knee cartilage by spiral dualMRI and relaxation mapping. Magn Reson Med 2023; 89:694-709. [PMID: 36300860 PMCID: PMC10017275 DOI: 10.1002/mrm.29487] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 09/20/2022] [Accepted: 09/21/2022] [Indexed: 12/13/2022]
Abstract
PURPOSE Daily activities including walking impose high-frequency cyclic forces on cartilage and repetitive compressive deformation. Analyzing cartilage deformation during walking would provide spatial maps of displacement and strain and enable viscoelastic characterization, which may serve as imaging biomarkers for early cartilage degeneration when the damage is still reversible. However, the time-dependent biomechanics of cartilage is not well described, and how defects in the joint impact the viscoelastic response is unclear. METHODS We used spiral acquisition with displacement-encoding MRI to quantify displacement and strain maps at a high frame rate (25 frames/s) in tibiofemoral joints. We also employed relaxometry methods (T1 , T1ρ , T2 , T2 *) on the cartilage. RESULTS Normal and shear strains were concentrated on the bovine tibiofemoral contact area during loading, and the defected joint exhibited larger compressive strains. We also determined a positive correlation between the change of T1ρ in cartilage after cyclic loading and increased compressive strain on the defected joint. Viscoelastic behavior was quantified by the time-dependent displacement, where the damaged joint showed increased creep behavior compared to the intact joint. This technique was also successfully demonstrated on an in vivo human knee showing the gradual change of displacement during varus load. CONCLUSION Our results indicate that spiral scanning with displacement encoding can quantitatively differentiate the damaged from intact joint using the strain and creep response. The viscoelastic response identified with this methodology could serve as biomarkers to detect defects in joints in vivo and facilitate the early diagnosis of joint diseases such as osteoarthritis.
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Affiliation(s)
- Woowon Lee
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, USA
| | - Emily Y. Miller
- Biomedical Engineering Program, University of Colorado Boulder, Boulder, CO, USA
| | - Hongtian Zhu
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, USA
| | - Callan M. Luetkemeyer
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, USA
| | - Stephanie E. Schneider
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, USA
| | - Corey P. Neu
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, USA
- Biomedical Engineering Program, University of Colorado Boulder, Boulder, CO, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA
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Castro NJ, Babakhanova G, Hu J, Athanasiou K. Nondestructive testing of native and tissue-engineered medical products: adding numbers to pictures. Trends Biotechnol 2022; 40:194-209. [PMID: 34315621 PMCID: PMC8772387 DOI: 10.1016/j.tibtech.2021.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 02/03/2023]
Abstract
Traditional destructive tests are used for quality assurance and control within manufacturing workflows. Their applicability to biomanufacturing is limited due to inherent constraints of the biomanufacturing process. To address this, photo- and acoustic-based nondestructive testing has risen in prominence to interrogate not only structure and function, but also to integrate quantitative measurements of biochemical composition to cross-correlate structural, compositional, and functional variances. We survey relevant literature related to single-mode and multimodal nondestructive testing of soft tissues, which adds numbers (quantitative measurements) to pictures (qualitative data). Native and tissue-engineered articular cartilage is highlighted because active biomanufacturing processes are being developed. Included are recent efforts and prominent trends focused on technologies for clinical and in-process biomanufacturing applications.
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Affiliation(s)
- Nathan J. Castro
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92617, USA
| | - Greta Babakhanova
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Jerry Hu
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92617, USA
| | - K.A. Athanasiou
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92617, USA,Correspondence:
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Effects of Loading and Boundary Conditions on the Performance of Ultrasound Compressional Viscoelastography: A Computational Simulation Study to Guide Experimental Design. MATERIALS 2021; 14:ma14102590. [PMID: 34065764 PMCID: PMC8156541 DOI: 10.3390/ma14102590] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/10/2021] [Accepted: 05/12/2021] [Indexed: 01/01/2023]
Abstract
Most biomaterials and tissues are viscoelastic; thus, evaluating viscoelastic properties is important for numerous biomedical applications. Compressional viscoelastography is an ultrasound imaging technique used for measuring the viscoelastic properties of biomaterials and tissues. It analyzes the creep behavior of a material under an external mechanical compression. The aim of this study is to use finite element analysis to investigate how loading conditions (the distribution of the applied compressional pressure on the surface of the sample) and boundary conditions (the fixation method used to stabilize the sample) can affect the measurement accuracy of compressional viscoelastography. The results show that loading and boundary conditions in computational simulations of compressional viscoelastography can severely affect the measurement accuracy of the viscoelastic properties of materials. The measurement can only be accurate if the compressional pressure is exerted on the entire top surface of the sample, as well as if the bottom of the sample is fixed only along the vertical direction. These findings imply that, in an experimental validation study, the phantom design should take into account that the surface area of the pressure plate must be equal to or larger than that of the top surface of the sample, and the sample should be placed directly on the testing platform without any fixation (such as a sample container). The findings indicate that when applying compressional viscoelastography to real tissues in vivo, consideration should be given to the representative loading and boundary conditions. The findings of the present simulation study will provide a reference for experimental phantom designs regarding loading and boundary conditions, as well as guidance towards validating the experimental results of compressional viscoelastography.
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Ghosh S, Cuevas VC, Seelbinder B, Neu CP. Image-Based Elastography of Heterochromatin and Euchromatin Domains in the Deforming Cell Nucleus. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2006109. [PMID: 33448065 PMCID: PMC7869959 DOI: 10.1002/smll.202006109] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/29/2020] [Indexed: 05/21/2023]
Abstract
Chromatin of the eukaryotic cell nucleus comprises microscopically dense heterochromatin and loose euchromatin domains, each with distinct transcriptional ability and roles in cellular mechanotransduction. While recent methods are developed to characterize the mechanics of nucleus, measurement of intranuclear mechanics remains largely unknown. Here, the development of "nuclear elastography," which combines microscopic imaging and computational modeling to quantify the relative elasticity of the heterochromatin and euchromatin domains, is described. Using contracting murine embryonic cardiomyocytes, nuclear elastography reveals that the heterochromatin is almost four times stiffer than the euchromatin at peak deformation. The relative elasticity between the two domains changes rapidly during the active deformation of the cardiomyocyte in the normal physiological condition but progresses more slowly in cells cultured in a mechanically stiff environment, although the relative stiffness at peak deformation does not change. Further, it is found that the disruption of the Klarsicht, ANC-1, Syne Homology domain of the Linker of Nucleoskeleton and Cytoskeleton complex compromises the intranuclear elasticity distribution resulting in elastically similar heterochromatin and euchromatin. These results provide insight into the elastography dynamics of heterochromatin and euchromatin domains and provide a noninvasive framework to further investigate the mechanobiological function of subcellular and subnuclear domains limited only by the spatiotemporal resolution of the acquired images.
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Affiliation(s)
- Soham Ghosh
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO
| | - Victor Crespo Cuevas
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO
| | - Benjamin Seelbinder
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO
| | - Corey P. Neu
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO
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Berry DB, Englund EK, Chen S, Frank LR, Ward SR. Medical imaging of tissue engineering and regenerative medicine constructs. Biomater Sci 2021; 9:301-314. [PMID: 32776044 PMCID: PMC8262082 DOI: 10.1039/d0bm00705f] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Advancement of tissue engineering and regenerative medicine (TERM) strategies to replicate tissue structure and function has led to the need for noninvasive assessment of key outcome measures of a construct's state, biocompatibility, and function. Histology based approaches are traditionally used in pre-clinical animal experiments, but are not always feasible or practical if a TERM construct is going to be tested for human use. In order to transition these therapies from benchtop to bedside, rigorously validated imaging techniques must be utilized that are sensitive to key outcome measures that fulfill the FDA standards for TERM construct evaluation. This review discusses key outcome measures for TERM constructs and various clinical- and research-based imaging techniques that can be used to assess them. Potential applications and limitations of these techniques are discussed, as well as resources for the processing, analysis, and interpretation of biomedical images.
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Affiliation(s)
- David B Berry
- Departments of NanoEngineering, University of California, San Diego, USA.
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10
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In vivo intervertebral disc deformation: intratissue strain patterns within adjacent discs during flexion-extension. Sci Rep 2021; 11:729. [PMID: 33436667 PMCID: PMC7804136 DOI: 10.1038/s41598-020-77577-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 11/10/2020] [Indexed: 01/29/2023] Open
Abstract
The biomechanical function of the intervertebral disc (IVD) is a critical indicator of tissue health and pathology. The mechanical responses (displacements, strain) of the IVD to physiologic movement can be spatially complex and depend on tissue architecture, consisting of distinct compositional regions and integrity; however, IVD biomechanics are predominately uncharacterized in vivo. Here, we measured voxel-level displacement and strain patterns in adjacent IVDs in vivo by coupling magnetic resonance imaging (MRI) with cyclic motion of the cervical spine. Across adjacent disc segments, cervical flexion-extension of 10° resulted in first principal and maximum shear strains approaching 10%. Intratissue spatial analysis of the cervical IVDs, not possible with conventional techniques, revealed elevated maximum shear strains located in the posterior disc (nucleus pulposus) regions. IVD structure, based on relaxometric patterns of T2 and T1ρ images, did not correlate spatially with functional metrics of strain. Our approach enables a comprehensive IVD biomechanical analysis of voxel-level, intratissue strain patterns in adjacent discs in vivo, which are largely independent of MRI relaxometry. The spatial mapping of IVD biomechanics in vivo provides a functional assessment of adjacent IVDs in subjects, and provides foundational biomarkers for elastography, differentiation of disease state, and evaluation of treatment efficacy.
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Albrecht M, Lucarelli P, Kulms D, Sauter T. Computational models of melanoma. Theor Biol Med Model 2020; 17:8. [PMID: 32410672 PMCID: PMC7222475 DOI: 10.1186/s12976-020-00126-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 04/29/2020] [Indexed: 02/08/2023] Open
Abstract
Genes, proteins, or cells influence each other and consequently create patterns, which can be increasingly better observed by experimental biology and medicine. Thereby, descriptive methods of statistics and bioinformatics sharpen and structure our perception. However, additionally considering the interconnectivity between biological elements promises a deeper and more coherent understanding of melanoma. For instance, integrative network-based tools and well-grounded inductive in silico research reveal disease mechanisms, stratify patients, and support treatment individualization. This review gives an overview of different modeling techniques beyond statistics, shows how different strategies align with the respective medical biology, and identifies possible areas of new computational melanoma research.
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Affiliation(s)
- Marco Albrecht
- Systems Biology Group, Life Science Research Unit, University of Luxembourg, 6, avenue du Swing, Belval, 4367 Luxembourg
| | - Philippe Lucarelli
- Systems Biology Group, Life Science Research Unit, University of Luxembourg, 6, avenue du Swing, Belval, 4367 Luxembourg
| | - Dagmar Kulms
- Experimental Dermatology, Department of Dermatology, Dresden University of Technology, Fetscherstraße 105, Dresden, 01307 Germany
| | - Thomas Sauter
- Systems Biology Group, Life Science Research Unit, University of Luxembourg, 6, avenue du Swing, Belval, 4367 Luxembourg
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Cai L, Nauman EA, Pedersen CBW, Neu CP. Finite deformation elastography of articular cartilage and biomaterials based on imaging and topology optimization. Sci Rep 2020; 10:7980. [PMID: 32409711 PMCID: PMC7224212 DOI: 10.1038/s41598-020-64723-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 04/17/2020] [Indexed: 01/17/2023] Open
Abstract
Tissues and engineered biomaterials exhibit exquisite local variation in stiffness that defines their function. Conventional elastography quantifies stiffness in soft (e.g. brain, liver) tissue, but robust quantification in stiff (e.g. musculoskeletal) tissues is challenging due to dissipation of high frequency shear waves. We describe new development of finite deformation elastography that utilizes magnetic resonance imaging of low frequency, physiological-level (large magnitude) displacements, coupled to an iterative topology optimization routine to investigate stiffness heterogeneity, including spatial gradients and inclusions. We reconstruct 2D and 3D stiffness distributions in bilayer agarose hydrogels and silicon materials that exhibit heterogeneous displacement/strain responses. We map stiffness in porcine and sheep articular cartilage deep within the bony articular joint space in situ for the first time. Elevated cartilage stiffness localized to the superficial zone is further related to collagen fiber compaction and loss of water content during cyclic loading, as assessed by independent T2 measurements. We additionally describe technical challenges needed to achieve in vivo elastography measurements. Our results introduce new functional imaging biomarkers, which can be assessed nondestructively, with clinical potential to diagnose and track progression of disease in early stages, including osteoarthritis or tissue degeneration.
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Affiliation(s)
- Luyao Cai
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, US
| | - Eric A Nauman
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, US
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, US
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, 47907, US
| | | | - Corey P Neu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, US.
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, 80309, US.
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Stamatiou K, Perleti G. Reply to: André Moreira de Assis, et al. Effects of Prostatic Artery Embolization on the Dynamic Component of Benign Prostate Hyperplasia as Assessed by Ultrasound Elastography: A Pilot Series. Cardiovasc Intervent Radiol 2019; 42:1660-1661. [DOI: 10.1007/s00270-019-02285-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 07/03/2019] [Indexed: 11/29/2022]
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14
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Leartprapun N, Iyer RR, Mackey CD, Adie SG. Spatial localization of mechanical excitation affects spatial resolution, contrast, and contrast-to-noise ratio in acoustic radiation force optical coherence elastography. BIOMEDICAL OPTICS EXPRESS 2019; 10:5877-5904. [PMID: 31799053 PMCID: PMC6865116 DOI: 10.1364/boe.10.005877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/30/2019] [Accepted: 10/06/2019] [Indexed: 05/05/2023]
Abstract
The notion that a spatially confined mechanical excitation would produce an elastogram with high spatial resolution has motivated the development of various elastography techniques with localized mechanical excitation. However, a quantitative investigation of the effects of spatial localization of mechanical excitation on the spatial resolution of elastograms is still lacking in optical coherence elastography (OCE). Here, we experimentally investigated the effect of spatial localization of acoustic radiation force (ARF) excitation on spatial resolution, contrast, and contrast-to-noise ratio (CNR) of dynamic uniaxial strain elastograms in dynamic ARF-OCE, based on a framework for analyzing the factors that influence the quality of the elastogram at different stages of the elastography workflow. Our results show that localized ARF excitation with a smaller acoustic focal spot size produced a strain elastogram with superior spatial resolution, contrast, and CNR. Our results also suggest that the spatial extent spanned by the displacement response in the sample may connect between the spatial localization of the mechanical excitation and the resulting elastogram quality. The elastography framework and experimental approach presented here may provide a basis for the quantitative analysis of elastogram quality in OCE that can be adapted and applied to different OCE systems and applications.
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Affiliation(s)
- Nichaluk Leartprapun
- Cornell University, Meinig School of Biomedical Engineering, Weill Hall, Ithaca, New York 14853, USA
| | - Rishyashring R. Iyer
- Cornell University, Meinig School of Biomedical Engineering, Weill Hall, Ithaca, New York 14853, USA
- Present address: University of Illinois at Urbana-Champaign, Beckman Institute for Advanced Science and Technology, Urbana, Illinois 61801, USA
| | - Colin D. Mackey
- Cornell University, Meinig School of Biomedical Engineering, Weill Hall, Ithaca, New York 14853, USA
| | - Steven G. Adie
- Cornell University, Meinig School of Biomedical Engineering, Weill Hall, Ithaca, New York 14853, USA
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15
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Ruland A, Gilmore KJ, Daikuara LY, Fay CD, Yue Z, Wallace GG. Quantitative ultrasound imaging of cell-laden hydrogels and printed constructs. Acta Biomater 2019; 91:173-185. [PMID: 31055120 DOI: 10.1016/j.actbio.2019.04.055] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/02/2019] [Accepted: 04/25/2019] [Indexed: 12/17/2022]
Abstract
In the present work we have revisited the application of quantitative ultrasound imaging (QUI) to cellular hydrogels, by using the reference phantom method (RPM) in combination with a local attenuation compensation algorithm. The investigated biological samples consisted of cell-laden collagen hydrogels with PC12 neural cells. These cell-laden hydrogels were used to calibrate the integrated backscattering coefficient (IBC) as a function of cell density, which was then used to generate parametric images of local cell density. The image resolution used for QUI and its impact on the relative IBC error was also investigated. Another important contribution of our work was the monitoring of PC12 cell proliferation. The cell number estimates obtained via the calibrated IBC compared well with data obtained using a conventional quantitative method, the MTS assay. Evaluation of spectral changes as a function of culture time also provided additional information on the cell cluster size, which was found to be in close agreement with that observed by microscopy. Last but not least, we also applied QUI on a 3D printed cellular construct in order to illustrate its capabilities for the evaluation of bioprinted structures. STATEMENT OF SIGNIFICANCE: While there is intensive research in the areas of polymer science, biology, and 3D bio-printing, there exists a gap in available characterisation tools for the non-destructive inspection of biological constructs in the three-dimensional domain, on the macroscopic scale, and with fast data acquisition times. Quantitative ultrasound imaging is a suitable characterization technique for providing essential information on the development of tissue engineered constructs. These results provide a detailed and comprehensive guide on the capabilities and limitations of the technique.
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16
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Xu H, Shi L, Chen S, Zhang X, An KN, Luo ZP. Viscoelasticity measurement of ex vivo bovine cartilage using Lamb wave method. ACTA ACUST UNITED AC 2018; 63:235019. [DOI: 10.1088/1361-6560/aaed5a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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17
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Menal MJ, Jorba I, Torres M, Montserrat JM, Gozal D, Colell A, Piñol-Ripoll G, Navajas D, Almendros I, Farré R. Alzheimer's Disease Mutant Mice Exhibit Reduced Brain Tissue Stiffness Compared to Wild-type Mice in both Normoxia and following Intermittent Hypoxia Mimicking Sleep Apnea. Front Neurol 2018; 9:1. [PMID: 29403429 PMCID: PMC5780342 DOI: 10.3389/fneur.2018.00001] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/03/2018] [Indexed: 01/23/2023] Open
Abstract
Background Evidence from patients and animal models suggests that obstructive sleep apnea (OSA) may increase the risk of Alzheimer's disease (AD) and that AD is associated with reduced brain tissue stiffness. Aim To investigate whether intermittent hypoxia (IH) alters brain cortex tissue stiffness in AD mutant mice exposed to IH mimicking OSA. Methods Six-eight month old (B6C3-Tg(APPswe,PSEN1dE9)85Dbo/J) AD mutant mice and wild-type (WT) littermates were subjected to IH (21% O2 40 s to 5% O2 20 s; 6 h/day) or normoxia for 8 weeks. After euthanasia, the stiffness (E) of 200-μm brain cortex slices was measured by atomic force microscopy. Results Two-way ANOVA indicated significant cortical softening and weight increase in AD mice compared to WT littermates, but no significant effects of IH on cortical stiffness and weight were detected. In addition, reduced myelin was apparent in AD (vs. WT), but no significant differences emerged in the cortex extracellular matrix components laminin and glycosaminoglycans when comparing baseline AD and WT mice. Conclusion AD mutant mice exhibit reduced brain tissue stiffness following both normoxia and IH mimicking sleep apnea, and such differences are commensurate with increased edema and demyelination in AD.
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Affiliation(s)
- Maria José Menal
- Unitat Biofísica I Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
| | - Ignasi Jorba
- Unitat Biofísica I Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.,Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Marta Torres
- Sleep Laboratory, Hospital Clinic Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Josep M Montserrat
- Sleep Laboratory, Hospital Clinic Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - David Gozal
- Department of Pediatrics, Section of Pediatric Sleep Medicine, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago, Chicago, IL, United States
| | - Anna Colell
- Department of Mort I Proliferació Cellular, Institut d'Investigacions Biomèdiques de Barcelona (IIBB-CSIC), IDIBAPS, CIBERNED, Madrid, Spain
| | - Gerard Piñol-Ripoll
- Unitat Trastorns Cognitius, Clinical Neuroscience Research, IRBLleida-Hospital Universitari Santa Maria Lleida, Lleida, Spain
| | - Daniel Navajas
- Unitat Biofísica I Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.,Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Isaac Almendros
- Unitat Biofísica I Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain.,Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
| | - Ramon Farré
- Unitat Biofísica I Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain.,Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
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18
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Chan DD, Cai L, Butz KD, Nauman EA, Dickerson DA, Jonkers I, Neu CP. Functional MRI can detect changes in intratissue strains in a full thickness and critical sized ovine cartilage defect model. J Biomech 2018; 66:18-25. [PMID: 29169631 PMCID: PMC5767131 DOI: 10.1016/j.jbiomech.2017.10.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 10/02/2017] [Accepted: 10/27/2017] [Indexed: 02/07/2023]
Abstract
Functional imaging of tissue biomechanics can reveal subtle changes in local softening and stiffening associated with disease or repair, but noninvasive and nondestructive methods to acquire intratissue measures in well-defined animal models are largely lacking. We utilized displacement encoded MRI to measure changes in cartilage deformation following creation of a critical-sized defect in the medial femoral condyle of ovine (sheep) knees, a common in situ and large animal model of tissue damage and repair. We prioritized visualization of local, site-specific variation and changes in displacements and strains following defect placement by measuring spatial maps of intratissue deformation. Custom data smoothing algorithms were developed to minimize propagation of noise in the acquired MRI phase data toward calculated displacement or strain, and to improve strain measures in high aspect ratio tissue regions. Strain magnitudes in the femoral, but not tibial, cartilage dramatically increased in load-bearing and contact regions especially near the defect locations, with an average 6.7% ± 6.3%, 13.4% ± 10.0%, and 10.0% ± 4.9% increase in first and second principal strains, and shear strain, respectively. Strain heterogeneity reflected the complexity of the in situ mechanical environment within the joint, with multiple tissue contacts defining the deformation behavior. This study demonstrates the utility of displacement encoded MRI to detect increased deformation patterns and strain following disruption to the cartilage structure in a clinically-relevant, large animal defect model. It also defines imaging biomarkers based on biomechanical measures, in particular shear strain, that are potentially most sensitive to evaluate damage and repair, and that may additionally translate to humans in future studies.
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Affiliation(s)
- Deva D Chan
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, United States; Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, United States
| | - Luyao Cai
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, United States
| | - Kent D Butz
- School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, United States
| | - Eric A Nauman
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, United States; School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, United States; BioRegeneration Technologies, Inc., West Lafayette, IN 47907, United States
| | - Darryl A Dickerson
- School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, United States; BioRegeneration Technologies, Inc., West Lafayette, IN 47907, United States
| | - Ilse Jonkers
- Kinesiology Department, KU Leuven, Leuven, Belgium
| | - Corey P Neu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, United States; Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO 80309, United States.
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19
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Wahlquist JA, DelRio FW, Randolph MA, Aziz AH, Heveran CM, Bryant SJ, Neu CP, Ferguson VL. Indentation mapping revealed poroelastic, but not viscoelastic, properties spanning native zonal articular cartilage. Acta Biomater 2017; 64:41-49. [PMID: 29037894 DOI: 10.1016/j.actbio.2017.10.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/07/2017] [Accepted: 10/03/2017] [Indexed: 02/07/2023]
Abstract
Osteoarthrosis is a debilitating disease affecting millions, yet engineering materials for cartilage regeneration has proven difficult because of the complex microstructure of this tissue. Articular cartilage, like many biological tissues, produces a time-dependent response to mechanical load that is critical to cell's physiological function in part due to solid and fluid phase interactions and property variations across multiple length scales. Recreating the time-dependent strain and fluid flow may be critical for successfully engineering replacement tissues but thus far has largely been neglected. Here, microindentation is used to accomplish three objectives: (1) quantify a material's time-dependent mechanical response, (2) map material properties at a cellular relevant length scale throughout zonal articular cartilage and (3) elucidate the underlying viscoelastic, poroelastic, and nonlinear poroelastic causes of deformation in articular cartilage. Untreated and trypsin-treated cartilage was sectioned perpendicular to the articular surface and indentation was used to evaluate properties throughout zonal cartilage on the cut surface. The experimental results demonstrated that within all cartilage zones, the mechanical response was well represented by a model assuming nonlinear biphasic behavior and did not follow conventional viscoelastic or linear poroelastic models. Additionally, 10% (w/w) agarose was tested and, as anticipated, behaved as a linear poroelastic material. The approach outlined here provides a method, applicable to many tissues and biomaterials, which reveals and quantifies the underlying causes of time-dependent deformation, elucidates key aspects of material structure and function, and that can be used to provide important inputs for computational models and targets for tissue engineering. STATEMENT OF SIGNIFICANCE Elucidating the time-dependent mechanical behavior of cartilage, and other biological materials, is critical to adequately recapitulate native mechanosensory cues for cells. We used microindentation to map the time-dependent properties of untreated and trypsin treated cartilage throughout each cartilage zone. Unlike conventional approaches that combine viscoelastic and poroelastic behaviors into a single framework, we deconvoluted the mechanical response into separate contributions to time-dependent behavior. Poroelastic effects in all cartilage zones dominated the time-dependent behavior of articular cartilage, and a model that incorporates tension-compression nonlinearity best represented cartilage mechanical behavior. These results can be used to assess the success of regeneration and repair approaches, as design targets for tissue engineering, and for development of accurate computational models.
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Affiliation(s)
- Joseph A Wahlquist
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, United States
| | - Frank W DelRio
- Applied Chemicals and Materials Division, Material Measurement Laboratory, National Institute of Standards and Technology, Boulder, CO, United States
| | - Mark A Randolph
- Department of Orthopaedic Surgery, Laboratory for Musculoskeletal Tissue Engineering, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Division of Plastic Surgery, Plastic Surgery Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Aaron H Aziz
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, United States; BioFrontiers Institute, University of Colorado, Boulder, CO, United States
| | - Chelsea M Heveran
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, United States
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, United States; BioFrontiers Institute, University of Colorado, Boulder, CO, United States; Material Science and Engineering Program, University of Colorado, Boulder, CO, United States
| | - Corey P Neu
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, United States; BioFrontiers Institute, University of Colorado, Boulder, CO, United States
| | - Virginia L Ferguson
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, United States; BioFrontiers Institute, University of Colorado, Boulder, CO, United States; Material Science and Engineering Program, University of Colorado, Boulder, CO, United States.
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20
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Jorba I, Menal MJ, Torres M, Gozal D, Piñol-Ripoll G, Colell A, Montserrat JM, Navajas D, Farré R, Almendros I. Ageing and chronic intermittent hypoxia mimicking sleep apnea do not modify local brain tissue stiffness in healthy mice. J Mech Behav Biomed Mater 2017; 71:106-113. [DOI: 10.1016/j.jmbbm.2017.03.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/01/2017] [Accepted: 03/03/2017] [Indexed: 01/08/2023]
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21
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Hernandez C, Exner AA. Predicting in vivo behavior of injectable, in situ-forming drug-delivery systems. Ther Deliv 2017; 8:479-483. [PMID: 28350230 PMCID: PMC10072068 DOI: 10.4155/tde-2017-0007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Christopher Hernandez
- Department of Radiology, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
| | - Agata A Exner
- Department of Radiology, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
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22
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Kennedy KM, Bhaw-Luximon A, Jhurry D. Cell-matrix mechanical interaction in electrospun polymeric scaffolds for tissue engineering: Implications for scaffold design and performance. Acta Biomater 2017; 50:41-55. [PMID: 28011142 DOI: 10.1016/j.actbio.2016.12.034] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/10/2016] [Accepted: 12/15/2016] [Indexed: 12/24/2022]
Abstract
Engineered scaffolds produced by electrospinning of biodegradable polymers offer a 3D, nanofibrous environment with controllable structural, chemical, and mechanical properties that mimic the extracellular matrix of native tissues and have shown promise for a number of tissue engineering applications. The microscale mechanical interactions between cells and electrospun matrices drive cell behaviors including migration and differentiation that are critical to promote tissue regeneration. Recent developments in understanding these mechanical interactions in electrospun environments are reviewed, with emphasis on how fiber geometry and polymer structure impact on the local mechanical properties of scaffolds, how altering the micromechanics cues cell behaviors, and how, in turn, cellular and extrinsic forces exerted on the matrix mechanically remodel an electrospun scaffold throughout tissue development. Techniques used to measure and visualize these mechanical interactions are described. We provide a critical outlook on technological gaps that must be overcome to advance the ability to design, assess, and manipulate the mechanical environment in electrospun scaffolds toward constructs that may be successfully applied in tissue engineering and regenerative medicine. STATEMENT OF SIGNIFICANCE Tissue engineering requires design of scaffolds that interact with cells to promote tissue development. Electrospinning is a promising technique for fabricating fibrous, biomimetic scaffolds. Effects of electrospun matrix microstructure and biochemical properties on cell behavior have been extensively reviewed previously; here, we consider cell-matrix interaction from a mechanical perspective. Micromechanical properties as a driver of cell behavior has been well established in planar substrates, but more recently, many studies have provided new insights into mechanical interaction in fibrillar, electrospun environments. This review provides readers with an overview of how electrospun scaffold mechanics and cell behavior work in a dynamic feedback loop to drive tissue development, and discusses opportunities for improved design of mechanical environments that are conducive to tissue development.
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23
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Koc MA, Raja SN, Hanson LA, Nguyen SC, Borys NJ, Powers AS, Wu S, Takano K, Swabeck JK, Olshansky JH, Lin L, Ritchie RO, Alivisatos AP. Characterizing Photon Reabsorption in Quantum Dot-Polymer Composites for Use as Displacement Sensors. ACS NANO 2017; 11:2075-2084. [PMID: 28110520 DOI: 10.1021/acsnano.6b08277] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The reabsorption of photoluminescence within a medium, an effect known as the inner filter effect (IFE), has been well studied in solutions, but has garnered less attention in regards to solid-state nanocomposites. Photoluminescence from a quantum dot (QD) can selectively excite larger QDs around it resulting in a net red-shift in the reemitted photon. In CdSe/CdS core/shell QD-polymer nanocomposites, we observe a large spectral red-shift of over a third of the line width of the photoluminescence of the nanocomposites over a distance of 100 μm resulting from the IFE. Unlike fluorescent dyes, which do not show a large IFE red-shift, QDs have a component of inhomogeneous broadening that originates from their size distribution and quantum confinement. By controlling the photoluminescence broadening as well as the sample dispersion and concentration, we show that the magnitude of the IFE within the nanocomposite can be tuned. We further demonstrate that this shift can be exploited in order to spectroscopically monitor the vertical displacement of a nanocomposite in a fluorescence microscope. Large energetic shifts in the measured emission with displacement can be maximized, resulting in a displacement sensor with submicrometer resolution. We further show that the composite can be easily attached to biological samples and is able to measure deformations with high temporal and spatial precision.
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Affiliation(s)
- Matthew A Koc
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Shilpa N Raja
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States
| | - Lindsey A Hanson
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Son C Nguyen
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- The Hamburg Centre for Ultrafast Imaging, University of Hamburg , Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Nicholas J Borys
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Molecular Foundry, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Alexander S Powers
- Department of Chemistry, University of California , Berkeley, California 94720, United States
| | - Siva Wu
- Biological Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Kaori Takano
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- JX Nippon Oil & Energy Corporation, 8 , Chidori-cho, Naka-ku, Yokohama-shi, Kanagawa 231-0815, Japan
| | - Joseph K Swabeck
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Jacob H Olshansky
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Liwei Lin
- Department of Mechanical Engineering, University of California , Berkeley, California 94720, United States
| | - Robert O Ritchie
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States
- Department of Mechanical Engineering, University of California , Berkeley, California 94720, United States
| | - A Paul Alivisatos
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States
- Kavli Energy NanoScience Institute , Berkeley, California 94720, United States
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24
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Juriga D, Nagy K, Jedlovszky-Hajdú A, Perczel-Kovách K, Chen YM, Varga G, Zrínyi M. Biodegradation and Osteosarcoma Cell Cultivation on Poly(aspartic acid) Based Hydrogels. ACS APPLIED MATERIALS & INTERFACES 2016; 8:23463-23476. [PMID: 27541725 DOI: 10.1021/acsami.6b06489] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Development of novel biodegradable and biocompatible scaffold materials with optimal characteristics is important for both preclinical and clinical applications. The aim of the present study was to analyze the biodegradability of poly(aspartic acid)-based hydrogels, and to test their usability as scaffolds for MG-63 osteoblast-like cells. Poly(aspartic acid) was fabricated from poly(succinimide) and hydrogels were prepared using natural amines as cross-linkers (diaminobutane and cystamine). Disulfide bridges were cleaved to thiol groups and the polymer backbone was further modified with RGD sequence. Biodegradability of the hydrogels was evaluated by experiments on the base of enzymes and cell culture medium. Poly(aspartic acid) hydrogels possessing only disulfide bridges as cross-links proved to be degradable by collagenase I. The MG-63 cells showed healthy, fibroblast-like morphology on the double cross-linked and RGD modified hydrogels. Thiolated poly(aspartic acid) based hydrogels provide ideal conditions for adhesion, survival, proliferation, and migration of osteoblast-like cells. The highest viability was found on the thiolated PASP gels while the RGD motif had influence on compacted cluster formation of the cells. These biodegradable and biocompatible poly(aspartic acid)-based hydrogels are promising scaffolds for cell cultivation.
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Affiliation(s)
- Dávid Juriga
- Laboratory of Nanochemistry, Department of Biophysics and Radiation Biology, Semmelweis University , Nagyvárad tér 4., H-1089 Budapest, Hungary
| | - Krisztina Nagy
- Department of Oral Biology, Semmelweis University , Nagyvárad tér 4., H-1089 Budapest, Hungary
| | - Angéla Jedlovszky-Hajdú
- Laboratory of Nanochemistry, Department of Biophysics and Radiation Biology, Semmelweis University , Nagyvárad tér 4., H-1089 Budapest, Hungary
| | - Katalin Perczel-Kovách
- Department of Oral Biology, Semmelweis University , Nagyvárad tér 4., H-1089 Budapest, Hungary
- Department in Community Dentistry, Semmelweis University , Üllői út 26., H-1085 Budapest, Hungary
| | - Yong Mei Chen
- State Key Laboratory for Strength and Vibration of Mechanical Structures, International Center for Applied Mechanics and School of Aerospace, Xi'an Jiaotong University , Xi'an 710049, China
| | - Gábor Varga
- Department of Oral Biology, Semmelweis University , Nagyvárad tér 4., H-1089 Budapest, Hungary
| | - Miklós Zrínyi
- Laboratory of Nanochemistry, Department of Biophysics and Radiation Biology, Semmelweis University , Nagyvárad tér 4., H-1089 Budapest, Hungary
- MTA-SE Molecular Biophysics Research Group, Hungarian Academy of Sciences , Széchenyi István tér 9., 1051 Budapest, Hungary
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