Cavitation rheology of the vitreous: mechanical properties of biological tissue

Zimberlin, Jessica A.; McManus, Jennifer J.; Crosby, Alfred J.

doi:10.1039/b925407b

Cited by 91 publications

(78 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Additionally, the reported studies involved the dissection of the eye and the removal of the vitreous humor, processes that drastically alter its biomechanics. Recently, [9] used an insertable probe for measurements in an intact eye cavity, Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

Localized viscoelasticity measurements with untethered intravitreal microrobots

Pokki

Ergeneman

Bergeles

et al. 2012

2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

View full text Add to dashboard Cite

Microrobots are a promising tool for medical interventions and micromanipulation. In this paper, we explore the concept of using microrobots for microrheology. Untethered magnetically actuated microrobots were used to characterize one of the most complex biofluids, the vitreous humor. In this work we began by experimentally characterizing the viscoelastic properties of an artificial vitreous humor. For comparison, its properties were also measured using special microcantilevers in an atomic force microscope (AFM) setup. Subsequently, an untethered device was used to study the vitreous humor of a porcine eye, which is a valid ex-vivo model of a human eye. Its viscoelasticity model was extracted, which was in agreement with the model of the artificial vitreous. The existing characterization methodology requires eye and vitreous humor dissection for the microrheology measurements. We envision that the method proposed here can be used in in vivo.

show abstract

Section: Introductionmentioning

confidence: 99%

Localized viscoelasticity measurements with untethered intravitreal microrobots

Pokki

Ergeneman

Bergeles

et al. 2012

2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

View full text Add to dashboard Cite

show abstract

“…Various techniques have been developed to measure the mechanical properties of the vitreous humor: nuclear magnetic resonance imaging for the liquefaction of the vitreous [10]; dynamic mechanical measurements with compression [11]; the relaxation of the scattering pattern in the human eye [12]; radiation force [13]; bulk measurements using cleated tools [14]; cavitation rheology [15]; and ultrasound image velocimetry [16]. Researchers qualitatively measured phenomena related to physiological changes in the eyes [10]–[12].…”

Section: Introductionmentioning

confidence: 99%

“…The shear storage moduli of the porcine vitreous ranged from 2.8 to 10 Pa [14]. Most recently, in vivo measurements of the mechanical properties of the vitreous humor were performed using the relationship between the applied pressure and the size of cavitation bubbles at the needle tip [15]. The results showed that the storage moduli of bovine vitreous were between 120 and 660 Pa [15].…”

Section: Introductionmentioning

confidence: 99%

Correspondence: spatial variations of viscoelastic properties of porcine vitreous humors

Yoon

Aglyamov

Karpiouk

et al. 2013

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

View full text Add to dashboard Cite

Using a microbubble-based acoustic radiation force approach, spatial variations of Young’s modulus and shear viscosity of the porcine vitreous humors in two groups— young pigs (6 months old) and mature pigs (2 to 3 years old)— were measured in situ. The measurements in these groups (4 specimens in each group) were performed in several positions along an anterior-to-posterior direction. At each position, microbubbles were generated by focusing a nanosecond pulsed laser beam and the displacement of each microbubble in response to an impulsive acoustic radiation force was measured every 10 μs using a custom-made high-pulse-repetition-frequency ultrasound system. Based on measured dynamics of the microbubble, Young’s modulus and shear viscosity at various locations of the vitreous were reconstructed. Young’s moduli of the young and mature porcine vitreous at anterior region were the highest, whereas the central region had the lowest values, indicating the clear spatial variations in the vitreous humor elasticity in both groups.

show abstract

“…11,12 It is an inexpensive, fast, and portable method that estimates the elastic modulus by measurement of the critical pressure (P c ) required for internal cavitation. Cavitation is induced by air pumped through a needle inserted into the sample.…”

Section: 10mentioning

confidence: 99%

“…The first is that because the analysis assumes a neo-Hookean strain energy function, cavitation rheometry has only been used to characterize materials that are elastic solids. 11,12,[16][17][18][19] To extend this method to viscoelastic materials, the assumption of neo-Hookean mechanics must be examined relative to their rheological behavior. The second limitation is that Eqs.…”

mentioning

confidence: 99%

Elasticity of microscale volumes of viscoelastic soft matter by cavitation rheometry

et al. 2014

View full text Add to dashboard Cite

Measurement of the elastic modulus of soft, viscoelastic liquids with cavitation rheometry is demonstrated for specimens as small as 1 ll by application of elasticity theory and experiments on semi-dilute polymer solutions. Cavitation rheometry is the extraction of the elastic modulus of a material, E, by measuring the pressure necessary to create a cavity within it [J. A. Zimberlin, N. Sanabria-DeLong, G. N. Tew, and A. J. Crosby, Soft Matter 3, 763-767 (2007)]. This paper extends cavitation rheometry in three ways. First, we show that viscoelastic samples can be approximated with the neo-Hookean model provided that the time scale of the cavity formation is measured. Second, we extend the cavitation rheometry method to accommodate cases in which the sample size is no longer large relative to the cavity dimension. Finally, we implement cavitation rheometry to show that the theory accurately measures the elastic modulus of viscoelastic samples with volumes ranging from 4 ml to as low as 1 ll. V C 2014 AIP Publishing LLC.[http://dx.doi.org/10.1063/1.4896108]The linear elastic modulus of a soft material is a mechanical property measurable by techniques such as mechanical rheometry, microrheology, and atomic force microscopy (AFM). 1,2 Needs for both in vivo characterization of linear elasticity (such as in tissue viability) as well as rapid measurement (such as in quality control applications) have driven recent methods development. [3][4][5] Mechanical rheometry typically requires approximately milliliter sample volumes and, if sample loading and testing durations are considered, requires as much as 5 min to test one specimen at one deformation frequency. Passive microrheology is a widely used technique to study the mechanical properties of small volumes (between $3 and 50 ll) of soft matter. One method of microrheology-which uses the multiple scattering technique of diffusing wave spectroscopy-requires as much as an hour of measurement time. This method can probe elastic moduli up to $2000 Pa. 1,6,7 Microrheology measurements can also be impacted by the stability of the dispersed probes and the heterogeneity of the material studied. 8,9 AFM can also be used to characterize the elastic modulus of very small volumes (<1 ll) of material; however, this technique requires long durations for measurements and sample preparation time. 3,10 The duration of these techniques makes them challenging for high throughput applications, while their lack of portability complicates their use as in vivo diagnostics.The cavitation rheometry technique of Zimberlin et al. characterizes the linear elastic modulus of soft matter with Young's modulus in the range of 0.12 kPa < E < 40 kPa. 11,12 It is an inexpensive, fast, and portable method that estimates the elastic modulus by measurement of the critical pressure (P c ) required for internal cavitation. Cavitation is induced by air pumped through a needle inserted into the sample. The critical pressure predicts the elastic modulus, E, through the theory of cavitation in an incompressib...

show abstract

Cavitation rheology of the vitreous: mechanical properties of biological tissue

Cited by 91 publications

References 25 publications

Localized viscoelasticity measurements with untethered intravitreal microrobots

Localized viscoelasticity measurements with untethered intravitreal microrobots

Correspondence: spatial variations of viscoelastic properties of porcine vitreous humors

Elasticity of microscale volumes of viscoelastic soft matter by cavitation rheometry

Contact Info

Product

Resources

About