A Cartilage Elastometer For Use In The Living Subject

Tkaczuk, H.; Norrbom, Henry; Werelind, Hans

doi:10.3109/03091908209040998

Cited by 6 publications

(4 citation statements)

References 4 publications

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“…These tests were originally developed in the material sciences for both hard solids (e.g., ceramics and metals) with more recent application to polymeric materials and are increasingly being applied to studies of biological tissues. Clinical indentation testing devices used for evaluating the mechanical properties of articular cartilage typically employ flat-end cylindrical or spherical probes, a few millimeters in diameter (Appleyard et al, 2001;Shepherd and Seedhom, 1997;Lyyra et al, 1995;Aspden et al, 1991;Tkaczuk, 1982). Such large-scale clinical indenters average the mechanical properties of the biological tissue over a large volume, i.e., over several mm 3 of material.…”

Section: Determining Cartilage Mechanical Properties By Indentation Testingmentioning

confidence: 99%

Dynamic Elastic Modulus of Porcine Articular Cartilage Determined at Two Different Levels of Tissue Organization by Indentation-Type Atomic Force Microscopy

Stolz

Raiteri

Daniels

et al. 2004

Biophysical Journal

421

382

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Cartilage stiffness was measured ex vivo at the micrometer and nanometer scales to explore structure-mechanical property relationships at smaller scales than has been done previously. A method was developed to measure the dynamic elastic modulus, |E(*)|, in compression by indentation-type atomic force microscopy (IT AFM). Spherical indenter tips (radius = approximately 2.5 microm) and sharp pyramidal tips (radius = approximately 20 nm) were employed to probe micrometer-scale and nanometer-scale response, respectively. |E(*)| values were obtained at 3 Hz from 1024 unloading response curves recorded at a given location on subsurface cartilage from porcine femoral condyles. With the microsphere tips, the average modulus was approximately 2.6 MPa, in agreement with available millimeter-scale data, whereas with the sharp pyramidal tips, it was typically 100-fold lower. In contrast to cartilage, measurements made on agarose gels, a much more molecularly amorphous biomaterial, resulted in the same average modulus for both indentation tips. From results of AFM imaging of cartilage, the micrometer-scale spherical tips resolved no fine structure except some chondrocytes, whereas the nanometer-scale pyramidal tips resolved individual collagen fibers and their 67-nm axial repeat distance. These results suggest that the spherical AFM tip is large enough to measure the aggregate dynamic elastic modulus of cartilage, whereas the sharp AFM tip depicts the elastic properties of its fine structure. Additional measurements of cartilage stiffness following enzyme action revealed that elastase digestion of the collagen moiety lowered the modulus at the micrometer scale. In contrast, digestion of the proteoglycans moiety by cathepsin D had little effect on |E(*)| at the micrometer scale, but yielded a clear stiffening at the nanometer scale. Thus, cartilage compressive stiffness is different at the nanometer scale compared to the overall structural stiffness measured at the micrometer and larger scales because of the fine nanometer-scale structure, and enzyme-induced structural changes can affect this scale-dependent stiffness differently.

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Section: Determining Cartilage Mechanical Properties By Indentation Testingmentioning

confidence: 99%

Dynamic Elastic Modulus of Porcine Articular Cartilage Determined at Two Different Levels of Tissue Organization by Indentation-Type Atomic Force Microscopy

Stolz

Raiteri

Daniels

et al. 2004

Biophysical Journal

421

382

View full text Add to dashboard Cite

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“…A key finding is that the AFM tip size is essential in measuring the properties of articular cartilage in health and arthritis. IT-AFM was compared with the results from instruments that use larger probes to test the stiffness of cartilage [ 33 , 34 , 35 , 36 , 37 ]. These clinical indentation testing devices test the cartilage with large probes and measure the average stiffness over big volumes, which obscures the small changes in cartilage properties.…”

Section: Development Of Fast It-afm For Clinical Tissue Diagnosismentioning

confidence: 99%

“…These clinical indentation testing devices test the cartilage with large probes and measure the average stiffness over big volumes, which obscures the small changes in cartilage properties. Hence, it is not feasible to detect differences between healthy and unhealthy types of arthritic cartilage using these large-scale clinical indenters [ 37 ]. Besides the possibility of using smaller indenter sizes, a driving factor for developing IT-AFM was our understanding that, in contrast to these classical clinical indenters, the actuators of an AFM exhibit much higher z-dimensional sensitivity of ~0.01 nm versus the ~1 μm provided by the (mechanical) clinical indenters.…”

Section: Development Of Fast It-afm For Clinical Tissue Diagnosismentioning

confidence: 99%

The Revolution in Breast Cancer Diagnostics: From Visual Inspection of Histopathology Slides to Using Desktop Tissue Analysers for Automated Nanomechanical Profiling of Tumours

Stolz

2024

Bioengineering

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We aim to develop new portable desktop tissue analysers (DTAs) to provide fast, low-cost, and precise test results for fast nanomechanical profiling of tumours. This paper will explain the reasoning for choosing indentation-type atomic force microscopy (IT-AFM) to reveal the functional details of cancer. Determining the subtype, cancer stage, and prognosis will be possible, which aids in choosing the best treatment. DTAs are based on fast IT-AFM at the size of a small box that can be made for a low budget compared to other clinical imaging tools. The DTAs can work in remote areas and all parts of the world. There are a number of direct benefits: First, it is no longer needed to wait a week for the pathology report as the test will only take 10 min. Second, it avoids the complicated steps of making histopathology slides and saves costs of labour. Third, computers and robots are more consistent, more reliable, and more economical than human workers which may result in fewer diagnostic errors. Fourth, the IT-AFM analysis is capable of distinguishing between various cancer subtypes. Fifth, the IT-AFM analysis could reveal new insights about why immunotherapy fails. Sixth, IT-AFM may provide new insights into the neoadjuvant treatment response. Seventh, the healthcare system saves money by reducing diagnostic backlogs. Eighth, the results are stored on a central server and can be accessed to develop strategies to prevent cancer. To bring the IT-AFM technology from the bench to the operation theatre, a fast IT-AFM sensor needs to be developed and integrated into the DTAs.

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“…in vivo and in situ, is required. Tkaczuk [23] conducted such experiments on knee-joint articular cartilage during open surgery and in vitro, using a custom-made indentation apparatus [24]. He found no significant differences in energy dissipation, total deformation, and residual deformation of the articular cartilage between in vivo and in vitro testing.…”

Section: Preservation and Storagementioning

confidence: 99%

Testing and modelling of soft connective tissues of joints: A review

Masouros

Parker

Hill

et al. 2009

The Journal of Strain Analysis for Engineering Design

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There is wealth of data from experimental and numerical methods of analysing and modelling soft connective tissues of joints. In recent years, the advances in computational and technological capabilities allowed for several aspects of the function and mechanical behaviour of soft connective tissues of joints to be explored. However, the nature of soft tissue poses a great challenge in characterizing its material behaviour in a repeatable and physiologically or clinically relevant manner. This review article attempts to present, critique, and suggest experimental and numerical methods that are associated with the function and mechanical response of soft connective tissues of joints.

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A Cartilage Elastometer For Use In The Living Subject

Cited by 6 publications

References 4 publications

Dynamic Elastic Modulus of Porcine Articular Cartilage Determined at Two Different Levels of Tissue Organization by Indentation-Type Atomic Force Microscopy

Dynamic Elastic Modulus of Porcine Articular Cartilage Determined at Two Different Levels of Tissue Organization by Indentation-Type Atomic Force Microscopy

The Revolution in Breast Cancer Diagnostics: From Visual Inspection of Histopathology Slides to Using Desktop Tissue Analysers for Automated Nanomechanical Profiling of Tumours

Testing and modelling of soft connective tissues of joints: A review

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