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Theory of Red Blood Cell Oscillations in an Ultrasound Field

Johansen K., Kimmel E., Postema M.

Archives of Acoustics

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2017

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Vol. 42, No. 1

121--126

EN

Manipulating particles in the blood pool with noninvasive methods has been of great interest in therapeutic delivery. Recently, it was demonstrated experimentally that red blood cells can be forced to translate and accumulate in an ultrasound field. This acoustic response of the red blood cells has been attributed to sonophores, gas pockets that are formed under the influence of a sound field in the inner-membrane leaflets of biological cells. In this paper, we propose a simpler model: that of the compressible membrane. We derive the spatio-temporal cell dynamics for a spherically symmetric single cell, whilst regarding the cell bilayer membrane as two monolayer Newtonian viscous liquids, separated by a thin gas void. When applying the newly-derived equations to a red blood cell, it is observed that the void inside the bilayer expands to multiples of its original thickness, even at clinically safe acoustic pressure amplitudes. For causing permanent cell rupture during expansion, however, the acoustic pressure amplitudes needed would have to surpass the inertial cavitation threshold by a factor 10. Given the incompressibility of the inner monolayer, the radial oscillations of a cell are governed by the same set of equations as those of a forced antibubble. Evidently, these equations must hold for liposomes under sonication, as well.

2

Simultaneous measurement of refractive index and thickness for optically transparent object with a dual-wavelength quantitative technique

Xu X., Wang Y., Xu Y., Jin W.

Optica Applicata

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2016

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Vol. 46, nr 4

597--605

EN

We present a new dual-wavelength quantitative measurement approach that can be employed for simultaneously measuring both the refractive index and the thickness of the homogenous specimen. This method is realized by dual-wavelength in-line phase-shifting digital holography, and then the phase images are obtained by using four-phase step algorithm for each wavelength separately. Based on computer simulation technology, the feasibility and the effectiveness of our proposed method are demonstrated by comparing our simulation results with the experimental results of the spherical silica bead and the red blood cell, respectively. Our work will provide some guidance in the experimental research for transparent phase objects.

3

3D morphological reconstruction of the red blood cell based on two phase images

Wang Y, Li Z, Ji Y, Xu Y, Bu M

Optica Applicata

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2015

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Vol. 45, nr 2

173--182

EN

As an important component of blood cells, the red blood cell plays a vital role in many diseases such as malaria and so on. Although quantitative phase imaging techniques can be used for homogeneous cellular thickness distribution to obtain ideal results, they cannot achieve 3D morphological distribution. In this paper, a new method is presented to get a 3D morphology image of red blood cell. With this method, only two cellular quantitative phase images obtained from two orthogonal directions are needed as original information. By using the grid method, the sample is divided into many small phase cubes, and then we take a layer’s cubes into calculation so that the 3D problem could be transformed into a 2D problem to elaborate. Then it can be applied to the tomographic imaging combined with the maximum entropy method according to the two orthogonal phase images. This method has been proved by a simulation of red blood cell. The results show that cellular morphological distribution can be achieved in detail very well just based on only two orthogonal phase images.

4

Mathematical model for biological cell deformation in a cylindrical pore

Szwast M., Suchecka T., Piątkiewicz W.

Chemical and Process Engineering

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2012

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Vol. 33, nr 3

385-396

EN

Some studies show that cells are able to penetrate through pores that are smaller than cell size. It concerns especially Red Blood Cells but it also may concern different types of biological cells. Such penetration of small pores is a very significant problem in the filtration process, for example in micro or ultrafiltration. Deformability of cells allows them to go through the porous membrane and contaminate permeate. This paper shows how cells can penetrate small cylindrical holes and tries to assess mechanical stress in a cell during this process. A new mathematical approach to this phenomenon was presented, based on assumptions that were made during the microscopic observation of Red Blood Cell aspiration into a small capillary. The computational model concerns Red Blood Cell geometry. The mathematical model allows to obtain geometrical relation as well as mechanical stress relations.