Chemical Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar 382355, Gujarat, India.
Soft Matter. 2020 Feb 26;16(8):2149-2163. doi: 10.1039/c9sm01516g.
The effectiveness of microbubbles as ultrasound contrast agents and targeted drug delivery vehicles depends on their persistence in blood. It is therefore necessary to understand the dissolution behavior of microbubbles in an aqueous medium. While there are several reports available in the literature on the dissolution of lipid microbubbles, there are no reports available on the dissolution kinetics of protein microbubbles. Moreover, shell parameters such as interfacial tension, shell resistance and shell elasticity/stiffness which characterize microbubble shells, have been reported for lipid shells but no such data are available for protein shells. Accordingly, this work was focused on capturing the dissolution behavior of protein microbubbles and estimation of shell parameters such as surface tension, shell resistance and shell elasticity. Bovine serum albumin (BSA) was used as a model protein and microbubbles were synthesized using sonication. During dissolution, a large portion of the protein shell was found to disengage from the gas-liquid interface after a stagnant dissolution phase, leading to a sudden disappearance of the microbubbles due to complete dissolution. In order to estimate shell parameters, microbubble dissolution kinetic data (radius vs. time) was fit numerically to a mass transfer model describing a microbubble dissolution process. Analysis of the results shows that the interfacial tension increases drastically and the shell resistance reduces significantly, as protein molecules leave the gas-liquid interface. Furthermore, the effect of processing conditions such as preheating temperature, microbubble size, and core gas and shell composition on the protein shell parameters was also evaluated.
作为超声造影剂和靶向药物输送载体的微泡的有效性取决于它们在血液中的稳定性。因此，有必要了解微泡在水介质中的溶解行为。尽管文献中有关于脂质微泡溶解的报道，但尚未有关于蛋白质微泡溶解动力学的报道。此外，微泡壳的特征参数，如界面张力、壳阻力和壳弹性/硬度，已经报道了脂质壳的参数，但没有关于蛋白质壳的参数。因此，这项工作集中于捕获蛋白质微泡的溶解行为，并估计表面张力、壳阻力和壳弹性等壳参数。牛血清白蛋白（BSA）被用作模型蛋白，使用超声处理来合成微泡。在溶解过程中，发现在停滞溶解阶段后，大部分蛋白质壳从气-液界面脱离，导致微泡由于完全溶解而突然消失。为了估计壳参数，通过数值拟合微泡溶解动力学数据（半径与时间）到描述微泡溶解过程的传质模型。结果分析表明，随着蛋白质分子离开气-液界面，界面张力急剧增加，壳阻力显著降低。此外，还评估了预处理温度、微泡大小、核气体和壳组成等处理条件对蛋白质壳参数的影响。
