Vibrometry as a noncontact alternative to dynamic and viscoelastic mechanical testing in cartilage

Abstract

Physiological loading of knee cartilage is highly dynamic and may contribute to the progression of osteoarthritis. Thus, an understanding of cartilage's dynamic mechanical properties is crucial in cartilage research. In this study, vibrometry was used as a fast (2 h), noncontact and novel alternative to the slower (30 h), traditional mechanical and biochemical assays for characterization of cartilage from the condyle, patella, trochlear groove and meniscus. Finite-element models predicted tissue resonant frequencies and bending modes, which strongly correlated with experiments ( R 2 = 0.93). Vibrometry-based viscoelastic properties significantly correlated with moduli from stress relaxation and creep tests, with correlation strengths reaching up to 0.78. Loss modulus also strongly correlated with glycosoaminoglycan (GAG) content. Dynamic properties measured by vibrometry significantly differed among various knee cartilages, ranging between 6.1 and 56.4 MPa. Interestingly, meniscus viscoelastic properties suggest that contrary to common belief, it may lack shock absorption abilities; instead, condylar hyaline cartilage may be a better shock absorber. These data demonstrate for the first time that vibrometry is a noncontact approach to dynamic mechanical characterization of hyaline and fibrocartilage cartilage with concrete relationships to standard quasi-static mechanical testing and biochemical composition. Thus, with a single tool, vibrometry greatly facilitates meeting multiple regulatory recommendations for mechanical characterization of cartilage replacements.

Ultra-wideband optical coherence elastography from acoustic to ultrasonic frequencies

“…6c , from which we determined μ 1 = 5.6 ± 0.2 MPa and μ 2 = 13.2 ± 0.9 MPa. These shear elastic moduli are within the range of previously reported values between ~2.3 MPa by MRI elastography 55 and 27.4 MPa by laser scanning vibrometer 56 .

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Yucatan Minipig Knee Meniscus Regional Biomechanics and Biochemical Structure Support its Suitability as a Large Animal Model for Translational Research

“…Compressive properties were assessed via creep indentation testing of punches measuring 3 mm in diameter and placed into an automated indentation machine while submerged in phosphate buffered saline (PBS), as previously described ( Brown et al, 2018 ; Espinosa et al, 2021b ). Briefly, tissue punches were tested using a 0.5 mN tare load followed by a 0.04–0.05 N test load to maintain ∼10% applied strain.…”

Characterization of drying-induced changes in moduli and internal stresses in a constrained gel using laser vibrometry

“…The estimated loss tangent values vary from 6 to 10%, and that range is consistent with the ranges reported for other multiphasic soft materials such as gelatin from bovine skin; 66 polyacrylamide hydrogels, 10 and cartilaginous tissues extracted from condyle, patella, and meniscus regions of bovine knee joints. 21 Note that damping can be introduced by a complex modulus in the physical equations of motion (eqn (1) and (2)) or modal viscous damping added to the ODEs obtained after Galerkins projection. Damping parameters in either case would be fitted to the measured modal damping ratios.…”

“…Vibration and wave-based characterization offers a viable alternative for soft materials. [20][21][22][23][24][25][26] For instance, laser vibrometry 21 is shown to characterize dynamic and viscoelastic properties of multiphasic biological tissues such as cartilage considerably faster than conventional techniques. 21 Studies utilized vibration techniques to understand parametric resonances in soft materials and water droplets; 27 develop variable stiffness artificial muscles for vibration absorption; 28 and achieve broadband vibration attenuation using soft materials.…”

“…[20][21][22][23][24][25][26] For instance, laser vibrometry 21 is shown to characterize dynamic and viscoelastic properties of multiphasic biological tissues such as cartilage considerably faster than conventional techniques. 21 Studies utilized vibration techniques to understand parametric resonances in soft materials and water droplets; 27 develop variable stiffness artificial muscles for vibration absorption; 28 and achieve broadband vibration attenuation using soft materials. 29 Vibration-based monitoring of mechanical properties of various plants also delivers important information on plant genetics and phenotyping.…”