Modeling complicated rheological behaviors in encapsulating shells of lipid-coated microbubbles accounting for nonlinear changes of both shell viscosity and elasticity
Modeling complicated rheological behaviors in encapsulating shells of lipid-coated microbubbles accounting for nonlinear changes of both shell viscosity and elasticity
复制标题
模拟脂质涂层微泡封装壳的复杂流变行为，解释壳粘度和弹性的非线性变化
DOI：
10.1088/0031-9155/58/4/985
复制
发表时间：
2013-02-21
影响因子：
3.5
通讯作者：
Zhang, Dong
中科院分区：
文献类型：
--
作者：
Li, Qian;Matula, Thomas J.;Zhang, Dong
超声造影剂（UCA）微泡的动态响应受到其包封壳性质（如壳的弹性和粘度）的显著影响。本文提出了一种新的模型，将非线性“交叉定律”应用于Marmottant模型中的粘滞项，来描述UCA微泡封装壳内复杂的流变行为。通过拟合高速光学成像系统和光散射系统测量的uca动态响应，验证了所提模型的正确性。实测半径-时间曲线与数值模拟结果的对比表明，该模型可以很好地模拟uca的“纯压缩”行为。在此基础上，计算了SonoVue微泡的壳弹性系数和粘滞系数，并与已有的UCA模型进行了比较。结果证实了现有模型能够降低泡壳参数对初始泡半径的依赖，这表明，考虑到壳弹性和壳粘度的非线性变化，现有模型可以更全面地描述UCA微泡封装壳的复杂流变特性（如“剪切变薄”和“应变软化”）。
It has been accepted that the dynamic responses of ultrasound contrast agent (UCA) microbubbles will be significantly affected by the encapsulating shell properties (e.g., shell elasticity and viscosity). In this work, a new model is proposed to describe the complicated rheological behaviors in an encapsulating shell of UCA microbubbles by applying the nonlinear 'Cross law' to the shell viscous term in the Marmottant model. The proposed new model was verified by fitting the dynamic responses of UCAs measured with either a highspeed optical imaging system or a light scattering system. The comparison results between the measured radius-time curves and the numerical simulations demonstrate that the 'compression-only' behavior of UCAs can be successfully simulated with the new model. Then, the shell elastic and viscous coefficients of SonoVue microbubbles were evaluated based on the new model simulations, and compared to the results obtained from some existing UCA models. The results confirm the capability of the current model for reducing the dependence of bubble shell parameters on the initial bubble radius, which indicates that the current model might be more comprehensive to describe the complex rheological nature (e. g., 'shear-thinning' and 'strain-softening') in encapsulating shells of UCA microbubbles by taking into account the nonlinear changes of both shell elasticity and shell viscosity.