B D Partain1, Q Zhang2, M Unni3, J Aldrich1, C M Rinaldi-Ramos4, S Narayanan2, K D Allen5. 1. J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA. 2. X-ray Science Division, Argonne National Laboratory, Lemont, IL, USA. 3. Department of Chemical Engineering, University of Florida, Gainesville, FL, USA. 4. J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA; Department of Chemical Engineering, University of Florida, Gainesville, FL, USA. 5. J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA; Department of Orthopaedics and Rehabilitation, University of Florida, Gainesville, FL, USA. Electronic address: kyle.allen@bme.ufl.edu.
Abstract
OBJECTIVE: Tissues have complex structures, comprised of solid and fluid phases. Improved understanding of interactions between joint fluid and extracellular matrix (ECM) is required in models of cartilage mechanics. X-ray photon correlation spectroscopy (XPCS) directly measures nanometer-scale dynamics and can provide insight into biofluid-biosolid interactions in cartilage. This study applies XPCS to evaluate dynamic interactions between intact cartilage and biofluids. DESIGN: Cartilage biopsies were collected from bovine femoral condyles. During XPCS measurements, cartilage samples were exposed to different fluids: deionized water, PBS, synovial fluid, or sonicated synovial fluid. ECM-biofluid interactions were also assessed at different length scales and different depths from the cartilage surface. RESULTS: Using XPCS, cartilage ECM mobility was detected at length scales from 50 to 207 nm. As length scale decreased, time scale for autocorrelation decay decreased, suggesting smaller ECM components are more mobile. ECM dynamics were slowed by dehydrating the sample, demonstrating XPCS assesses matrix mobility in hydrated environments. At all length scales, the matrix was more mobile in deionized water and slowest in synovial fluid. Using the 207 nm length scale assessment, ECM dynamics in synovial fluid were fastest at the cartilage surface and progressively slowed as depth into the sample increased, demonstrating XPCS can assess spatial distribution of ECM dynamics. Finally, ECM mobility increased for degraded synovial fluid. CONCLUSIONS: This study demonstrates the potential of XPCS to provide unique insights into nanometer-scale cartilage ECM mobility in a spatially resolved manner and illustrates the importance of biosolid-biofluid interactions in dictating ECM dynamics.
OBJECTIVE: Tissues have complex structures, comprised of solid and fluid phases. Improved understanding of interactions between joint fluid and extracellular matrix (ECM) is required in models of cartilage mechanics. X-ray photon correlation spectroscopy (XPCS) directly measures nanometer-scale dynamics and can provide insight into biofluid-biosolid interactions in cartilage. This study applies XPCS to evaluate dynamic interactions between intact cartilage and biofluids. DESIGN: Cartilage biopsies were collected from bovine femoral condyles. During XPCS measurements, cartilage samples were exposed to different fluids: deionized water, PBS, synovial fluid, or sonicated synovial fluid. ECM-biofluid interactions were also assessed at different length scales and different depths from the cartilage surface. RESULTS: Using XPCS, cartilage ECM mobility was detected at length scales from 50 to 207 nm. As length scale decreased, time scale for autocorrelation decay decreased, suggesting smaller ECM components are more mobile. ECM dynamics were slowed by dehydrating the sample, demonstrating XPCS assesses matrix mobility in hydrated environments. At all length scales, the matrix was more mobile in deionized water and slowest in synovial fluid. Using the 207 nm length scale assessment, ECM dynamics in synovial fluid were fastest at the cartilage surface and progressively slowed as depth into the sample increased, demonstrating XPCS can assess spatial distribution of ECM dynamics. Finally, ECM mobility increased for degraded synovial fluid. CONCLUSIONS: This study demonstrates the potential of XPCS to provide unique insights into nanometer-scale cartilage ECM mobility in a spatially resolved manner and illustrates the importance of biosolid-biofluid interactions in dictating ECM dynamics.
Authors: Qingteng Zhang; Eric M Dufresne; Suresh Narayanan; Piotr Maj; Anna Koziol; Robert Szczygiel; Pawel Grybos; Mark Sutton; Alec R Sandy Journal: J Synchrotron Radiat Date: 2018-08-02 Impact factor: 2.616
Authors: Ian A Stokes; Salman Chegini; Stephen J Ferguson; Mack G Gardner-Morse; James C Iatridis; Jeffrey P Laible Journal: Ann Biomed Eng Date: 2010-03-20 Impact factor: 3.934