Use of Indentation Test to Determine the Proteoglycan Content of Articular Cartilage

2002 ◽  
Author(s):  
Xin Lu ◽  
Daniel D. Sun ◽  
X. Edward Guo ◽  
Hui Chen ◽  
W. Michael Lai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Articular Cartilage ◽  
Indentation Test ◽  
Solid Matrix ◽  
Interstitial Fluid Flow ◽  
Fibrous Network ◽  
Indentation Experiment ◽  
Proteoglycan Content ◽  
Creep And Stress Relaxation ◽  
First Time

The indentation experiment has been widely used to determine mechanical properties of articular cartilage [e.g., 1–3]. This method does not disrupt the fibrous network of the tissue nor does it require removing the tissue from the underlying bone. The biphasic indentation theory has been successfully used to determine the effect of interstitial fluid flow and pressurization (load support) on the creep and stress-relaxation behaviors of articular cartilage, and to determine its apparent mechanical properties (i.e., the elastic moduli of the extracellular solid matrix and its permeability) [1, 3]. However, due to its proteoglycan content, articular cartilage is a charged tissue with a high fixed charge density (FCD) [4]. Proteoglycan and collagen contents, water, etc, vary with age or with orthteoarthritis [4, 5]. The FCD plays important physicochemical roles in load support and mechano-electrochemial behaviors of the tissue and also regulates chondrocyte biosynthetic activities [4–7]. It is therefore important to develop an effective technique to determine not only the mechanical properties but also the electrochemical property (e.g., FCD) of the tissue, simultaneously and at the same location. The purpose of the current study is to determine, for the first time, both the mechanical properties and FCD of the extracellular matrix using an indentation test.

Permeability of Human Glenohumeral Joint Cartilage

1999 ◽  
Author(s):  
Anna Stankiewicz ◽  
Gerard A. Ateshian ◽  
Louis U. Bigliani ◽  
Van C. Mow
Keyword(s):  
Mechanical Properties ◽  
Articular Cartilage ◽  
Interstitial Fluid ◽  
Glenohumeral Joint ◽  
Solid Matrix ◽  
Joint Cartilage ◽  
Frictional Drag ◽  
Diarthrodial Joints ◽  
Flow Through ◽  
Fluid Pressurization

Abstract The nearly frictionless lubrication in diarthrodial joints and load support within articular cartilage depends on its mechanical properties. It has been shown that the majority of applied loads on cartilage are supported by interstitial fluid pressurization (Ateshian et al., 1994) which results from the frictional drag of flow through the porous permeable solid matrix. The duration and magnitude of this pressurization are a function of the permeability of cartilage (Lai et al., 1981).

Direct Hydraulic Permeability Measurements of Agarose Hydrogels Used as Cell Scaffolds

1999 ◽  
Author(s):  
Michael A. Soltz ◽  
Anna Stankiewicz ◽  
Gerard Ateshian ◽  
Robert L. Mauck ◽  
Clark T. Hung
Keyword(s):  
Fluid Flow ◽  
Articular Cartilage ◽  
Interstitial Fluid ◽  
Convective Transport ◽  
Hydraulic Permeability ◽  
Interstitial Fluid Flow ◽  
Pass Through ◽  
Fluid Pressurization ◽  
First Time

Abstract The objective of this study was to determine the intrinsic hydraulic permeability of 2% agarose hydrogels. Two-percent agarose was chosen because it is a concentration typically used for encapsulation of chondrocytes in suspension cultures [3–5], Hydraulic permeability is a measure of the relative ease by which fluid can pass through a material. Importantly, it governs the level of interstitial fluid flow as well as the interstitial fluid pressurization that is generated in a material during loading. Fluid pressurization is the source of the unique load-bearing and lubrication properties of articular cartilage [1,17] and represents a major component of the in vivo chondrocyte environment. We have previously reported that 2% agarose hydrogels can support fluid pressurization, albeit to a significantly lesser degree than articular cartilage [18]. Interstitial fluid flow gives rise to convective transport of nutrients and ions [6,7] and matrix compaction [9] which may serve as important stimuli to chondrocytes. We report for the first time the strain-dependent hydraulic permeability of 2% agarose hydrogels.

Nanoindentation of In Situ Polymers in Hydroxyapatite/Poly-L-Lactide Biocomposites

2006 ◽  
Vol 518 ◽  
pp. 501-506 ◽  
Author(s):  
I. Balać ◽  
Chak Yin Tang ◽  
Chi Pong Tsui ◽  
Da Zhu Chen ◽  
P.S. Uskoković ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Indentation Test ◽  
Polymer Processing ◽  
Elastic Behavior ◽  
Element Analysis ◽  
High Resolution Measurement ◽  
Resolution Measurement ◽  
The Matrix ◽  
Indentation Experiment

In order to obtain more accurate properties after compaction of hydroxyapatite (HAp)/poly-L-lactide (PLLA) composite, high-resolution measurement of mechanical properties method is proposed to determine the properties of each phase separately, leading to information that are valuable for the development of new materials as well as for predictive modeling purposes. The PLLA polymer processing conditions used in hot pressing of the composite strongly influence final mechanical properties of the material in the solid state. Since the aim was to measure PLLA material properties, acceptable findings could only be made using unconstrained, cured in situ nanoindentation tests. A finite element analysis of the in situ indentation experiment was performed to determine required size of plain polymer area, needed for indentation test, which would minimize the particle influence on the matrix elastic behavior.

Compressive Properties of Mouse Articular Cartilage Determined in a Novel Micro-Indentation Test Method and Biphasic Finite Element Model

2006 ◽  
Vol 128 (5) ◽  
pp. 766-771 ◽  
Author(s):  
Li Cao ◽  
Inchan Youn ◽  
Farshid Guilak ◽  
Lori A Setton
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Articular Cartilage ◽  
Indentation Test ◽  
Small Animal ◽  
Element Model ◽  
Indentation Testing ◽  
Compressive Properties ◽  
Biphasic Finite Element ◽  
Micro Indentation

The mechanical properties of articular cartilage serve as important measures of tissue function or degeneration, and are known to change significantly with osteoarthritis. Interest in small animal and mouse models of osteoarthritis has increased as studies reveal the importance of genetic background in determining predisposition to osteoarthritis. While indentation testing provides a method of determining cartilage mechanical properties in situ, it has been of limited value in studying mouse joints due to the relatively small size of the joint and thickness of the cartilage layer. In this study, we developed a micro-indentation testing system to determine the compressive and biphasic mechanical properties of cartilage in the small joints of the mouse. A nonlinear optimization program employing a genetic algorithm for parameter estimation, combined with a biphasic finite element model of the micro-indentation test, was developed to obtain the biphasic, compressive material properties of articular cartilage. The creep response and material properties of lateral tibial plateau cartilage were obtained for wild-type mouse knee joints, by the micro-indentation testing and optimization algorithm. The newly developed genetic algorithm was found to be efficient and accurate when used with the finite element simulations for nonlinear optimization to the experimental creep data. The biphasic mechanical properties of mouse cartilage in compression (average values: Young’s modulus, 2.0MPa; Poisson’s ratio, 0.20; and hydraulic permeability, 1.1×10−16m4∕N‐s) were found to be of similar orders of magnitude as previous findings for other animal cartilages, including human, bovine, rat, and rabbit and demonstrate the utility of the new test methods. This study provides the first available data for biphasic compressive properties in mouse cartilage and suggests a promising method for detecting altered cartilage mechanics in small animal models of osteoarthritis.

scholarly journals Non-Destructive Spectroscopic Assessment of High and Low Weight Bearing Articular Cartilage Correlates with Mechanical Properties

Cartilage ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 480-490 ◽  
Author(s):  
James P. Karchner ◽  
Farzad Yousefi ◽  
Stephanie R. Bitman ◽  
Kurosh Darvish ◽  
Nancy Pleshko
Keyword(s):  
Mechanical Properties ◽  
Articular Cartilage ◽  
Near Infrared ◽  
Fiber Optic ◽  
Weight Bearing ◽  
Short Term ◽  
Low Weight ◽  
Proteoglycan Content ◽  
Non Destructive ◽  
Femoral Condyles

Objective Autologous articular cartilage (AC) harvested for repair procedures of high weight bearing (HWB) regions of the femoral condyles is typically obtained from low weight bearing (LWB) regions, in part due to the lack of non-destructive techniques for cartilage composition assessment. Here, we demonstrate that infrared fiber optic spectroscopy can be used to non-destructively evaluate variations in compositional and mechanical properties of AC across LWB and HWB regions. Design AC plugs ( N = 72) were harvested from the patellofemoral groove of juvenile bovine stifle joints, a LWB region, and femoral condyles, a HWB region. Near-infrared (NIR) and mid-infrared (MIR) fiber optic spectra were collected from plugs, and indentation tests were performed to determine the short-term and equilibrium moduli, followed by gravimetric water and biochemical analysis. Results LWB tissues had a significantly greater amount of water determined by NIR and gravimetric assay. The moduli generally increased in tissues from the patellofemoral groove to the condyles, with HWB condyle cartilage having significantly higher moduli. A greater amount of proteoglycan content was also found in HWB tissues, but no differences in collagen content. In addition, NIR-determined water correlated with short-term modulus and proteoglycan content ( R = −0.40 and −0.31, respectively), and a multivariate model with NIR data was able to predict short-term modulus within 15% error. Conclusions The properties of tissues from LWB regions differ from HWB tissues and can be determined non-destructively by infrared fiber optic spectroscopy. Clinicians may be able to use this modality to assess AC prior to harvesting osteochondral grafts for focal defect repair.

scholarly journals A Triphasic Orthotropic Laminate Model for Cartilage Curling Behavior: Fixed Charge Density Versus Mechanical Properties Inhomogeneity

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Leo Q. Wan ◽  
X. Edward Guo ◽  
Van C. Mow
Keyword(s):  
Articular Cartilage ◽  
Osmotic Pressure ◽  
Structural Model ◽  
Articular Surface ◽  
Mixture Theory ◽  
Solid Matrix ◽  
Linear Elastic ◽  
Orthotropic Properties ◽  
First Time

Osmotic pressure and associated residual stresses play important roles in cartilage development and biomechanical function. The curling behavior of articular cartilage was believed to be the combination of results from the osmotic pressure derived from fixed negative charges on proteoglycans and the structural and compositional and material property inhomogeneities within the tissue. In the present study, the in vitro swelling and curling behaviors of thin strips of cartilage were analyzed with a new structural model using the triphasic mixture theory with a collagen-proteoglycan solid matrix composed of a three-layered laminate with each layer possessing a distinct set of orthotropic properties. A conewise linear elastic matrix was also incorporated to account for the well-known tension-compression nonlinearity of the tissue. This model can account, for the first time, for the swelling-induced curvatures found in published experimental results on excised cartilage samples. The results suggest that for a charged-hydrated soft tissue, such as articular cartilage, the balance of proteoglycan swelling and the collagen restraining within the solid matrix is the origin of the in situ residual stress, and that the layered collagen ultrastructure, e.g., relatively dense and with high stiffness at the articular surface, play the dominate role in determining curling behaviors of such tissues.

Mechanical Stimulation Enhances Collagen Synthesis in Periosteum-Derived Cartilage

2009 ◽  
Author(s):  
Agnese Ravetto ◽  
Linda M. Kock ◽  
Corrinus C. van Donkelaar ◽  
Keita Ito
Keyword(s):  
Mechanical Properties ◽  
Articular Cartilage ◽  
Mechanical Loading ◽  
Cartilage Repair ◽  
Structural Organization ◽  
Collagen Synthesis ◽  
Engineer Cartilage ◽  
High Prevalence ◽  
Proteoglycan Content ◽  
Tissue Engineer Cartilage

High prevalence of osteoarthritis and poor intrinsic healing capacity of articular cartilage create a demand for cell-based strategies for cartilage repair. It is possible to tissue engineer cartilage with almost native proteoglycan content, but collagen reaches only 15% to 35% of the native content. Also its natural arcade-like structural organization is not reproduced. These drawbacks contribute to its insufficient load-bearing properties. It is generally believed that the application of mechanical loading during culturing will improve the mechanical properties. However, a suitable mechanical loading regime has not yet been established.

scholarly journals An Alternative Method to Characterize the Quasi-Static, Nonlinear Material Properties of Murine Articular Cartilage

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Alexander Kotelsky ◽  
Chandler W. Woo ◽  
Luis F. Delgadillo ◽  
Michael S. Richards ◽  
Mark R. Buckley
Keyword(s):  
Mechanical Properties ◽  
Articular Cartilage ◽  
Objective Measure ◽  
Nonlinear Material ◽  
Solid Matrix ◽  
Strain Mapping ◽  
Element Analysis ◽  
Static Mechanical ◽  
Tissue Degradation ◽  
Inverse Finite Element Analysis

With the onset and progression of osteoarthritis (OA), articular cartilage (AC) mechanical properties are altered. These alterations can serve as an objective measure of tissue degradation. Although the mouse is a common and useful animal model for studying OA, it is extremely challenging to measure the mechanical properties of murine AC due to its small size (thickness < 50 μm). In this study, we developed novel and direct approach to independently quantify two quasi-static mechanical properties of mouse AC: the load-dependent (nonlinear) solid matrix Young's modulus (E) and drained Poisson's ratio (ν). The technique involves confocal microscope-based multiaxial strain mapping of compressed, intact murine AC followed by inverse finite element analysis (iFEA) to determine E and ν. Importantly, this approach yields estimates of E and ν that are independent of the initial guesses used for iterative optimization. As a proof of concept, mechanical properties of AC on the medial femoral condyles of wild-type mice were obtained for both trypsin-treated and control specimens. After proteolytic tissue degradation induced through trypsin treatment, a dramatic decrease in E was observed (compared to controls) at each of the three tested loading conditions. A significant decrease in ν due to trypsin digestion was also detected. These data indicate that the method developed in this study may serve as a valuable tool for comparative studies evaluating factors involved in OA pathogenesis using experimentally induced mouse OA models.

Biphasic Poroviscoelastic Simulation of the Unconfined Compression of Articular Cartilage: I—Simultaneous Prediction of Reaction Force and Lateral Displacement

2000 ◽  
Vol 123 (2) ◽  
pp. 191-197 ◽  
Author(s):  
Mark R. DiSilvestro ◽  
Qiliang Zhu ◽  
Marcy Wong ◽  
Jukka S. Jurvelin ◽  
Jun-Kyo Francis Suh
Keyword(s):  
Fluid Flow ◽  
Articular Cartilage ◽  
Solid Phase ◽  
Lateral Displacement ◽  
Transverse Isotropy ◽  
Reaction Force ◽  
Solid Matrix ◽  
Inviscid Fluid ◽  
Unconfined Compression ◽  
Interstitial Fluid Flow

This study investigated the ability of the linear biphasic poroelastic (BPE) model and the linear biphasic poroviscoelastic (BPVE) model to simultaneously predict the reaction force and lateral displacement exhibited by articular cartilage during stress relaxation in unconfined compression. Both models consider articular cartilage as a binary mixture of a porous incompressible solid phase and an incompressible inviscid fluid phase. The BPE model assumes the solid phase is elastic, while the BPVE model assumes the solid phase is viscoelastic. In addition, the efficacy of two additional models was also examined, i.e., the transversely isotropic BPE (TIBPE) model, which considers transverse isotropy of the solid matrix within the framework of the linear BPE model assumptions, and a linear viscoelastic solid (LVE) model, which assumes that the viscoelastic behavior of articular cartilage is solely governed by the intrinsic viscoelastic nature of the solid matrix, independent of the interstitial fluid flow. It was found that the BPE model was able to accurately account for the lateral displacement, but unable to fit the short-term reaction force data of all specimens tested. The TIBPE model was able to account for either the lateral displacement or the reaction force, but not both simultaneously. The LVE model was able to account for the complete reaction force, but unable to fit the lateral displacement measured experimentally. The BPVE model was able to completely account for both lateral displacement and reaction force for all specimens tested. These results suggest that both the fluid flow-dependent and fluid flow-independent viscoelastic mechanisms are essential for a complete simulation of the viscoelastic phenomena of articular cartilage.

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