Growth and dissolution of an encapsulated contrast microbubble: effects of encapsulation permeability.
Growth and dissolution of an encapsulated contrast microbubble: effects of encapsulation permeability.
复制标题
DOI：
10.1016/j.ultrasmedbio.2009.04.010
复制
发表时间：
2009-08
影响因子：
2.9
通讯作者：
Jain, Pankaj
中科院分区：
文献类型：
--
作者：
Sarkar, Kausik;Katiyar, Amit;Jain, Pankaj
关键词：
从封装的微泡气体扩散建模使用一个明确的线性关系，通过封装的气体渗透。考虑了单一气体（空气）和多种气体（气泡内的全氟化碳和溶解在周围液体中的空气）的情况。得到了一个解析表达式的溶解时间为一个封装的气泡，它表明，对于小的渗透性的溶解时间线性增加，降低渗透性。一个全氟化碳填充的对比微泡，如地塞米松预计将经历一个短暂的增长，由于空气注入之前，它溶解与以前的实验结果一致。生长阶段只发生在具有临界值的初始部分摩尔分数的全氟化碳相对于空气的气泡。根据经验获得的属性值，表面张力为25 mN/m的2.5微米直径（与Definity相同）脂质涂层八氟丙烷气泡的溶解时间预测在空气饱和介质中的寿命为42分钟。壳层渗透率、表面张力、八氟丙烷的相对摩尔分数等性质的变化对气泡生长和溶解的时间尺度的影响进行了研究，包括适当的渐近尺度。溶解动力学与渗透率成比例，因为当时间与渗透率无量纲化时，不同渗透率的曲线在单一曲线上塌陷。对填充有其他气体（非八氟丙烷、全氟化碳和六氟化硫）的气泡的研究表明，由于较大气体分子的溶解度和扩散率较低，溶解时间较长。对于这种微米尺寸的封装气泡，只有在极低的表面张力（<1 mN/m）或极端过饱和时才可能有数小时的寿命。
Gas diffusion from an encapsulated microbubble is modeled using an explicit linear relation for gas permeation through the encapsulation. Both the cases of single gas (air) and multiple gases (perfluorocarbon inside the bubble and air dissolved in surrounding liquid) are considered. An analytical expression for the dissolution time for an encapsulated air bubble is obtained; it showed that for small permeability the dissolution time increases linearly with decreasing permeability. A perfluorocarbon-filled contrast microbubble such as Definity was predicted to experience a transient growth due to air infusion before it dissolves in conformity with previous experimental findings. The growth phase occurs only for bubbles with a critical value of initial partial mole fraction of perfluorocarbon relative to air. With empirically obtained property values, the dissolution time of a 2.5 micron diameter (same as that of Definity) lipid coated octafluoropropane bubble with surface tension 25 mN/m predicts a lifetime of 42 minutes in an air saturated medium. The properties such as shell permeability, surface tension, relative mole fraction of octafluoropropane are varied to investigate their effects on the time scales of bubble growth and dissolution including their asymptotic scalings where appropriate. The dissolution dynamics scales with permeability, in that when the time is nondimensioanlized with permeability, curves for different permeabilities collapse on a single curve. Investigation of bubbles filled with other gases (non-octafluoropropane perfluorocarbon and sulfur hexafluoride) indicates longer dissolution time due to lower solubility and lower diffusivity for larger gas molecules. For such micron size encapsulated bubbles, lifetime of hours is possible only at extremely low surface tension (<1mN/m) or at extreme oversaturation.
登录
查看更多内容
影响因子：
2.9
作者：
Chang, PH;Shung, KK;Levene, HB
通讯作者：
Levene, HB
影响因子：
4.2
作者：
DEJONG, N;CORNET, R;LANCEE, CT
通讯作者：
LANCEE, CT
影响因子：
2.9
作者：
Chatterjee, D;Sarkar, K
通讯作者：
Sarkar, K
影响因子：
4.6
作者：
Chatterjee, D;Jain, P;Sarkar, K
通讯作者：
Sarkar, K
影响因子：
3.3
作者：
Ciani, I;Burt, DP;Unwin, PR
通讯作者：
Unwin, PR