Li Thomas H, Stachowiak Jeanne C, Fletcher Daniel A
Department of Mechanical Engineering, University of California, Berkeley, California, USA.
Methods Enzymol. 2009;465:75-94. doi: 10.1016/S0076-6879(09)65004-7.
Controlling the contents of liposomes and vesicles is essential for their use in medicine, biotechnology, and basic research. Cargos such as proteins, DNA, and RNA are of growing interest for therapeutic applications as well as for fundamental studies of cellular organization and function, but controlled encapsulation and mixing of biomolecules within vesicles has been a challenge. Recently, microfluidic encapsulation has been shown to efficiently load arbitrary solutions of biomolecules into unilamellar vesicles. This method utilizes a piezoelectrically driven liquid jet to deform a planar bilayer and form a vesicle, with the fluid vortex formed by the jet mixing the solution in the jet with the surrounding solution. Here, we describe the equipment and protocol used for loading mixtures within unilamellar vesicles by microfluidic encapsulation, and we measure the encapsulated fraction to be 79+/-5% using a falling vesicle technique. Additionally, we find that the presence of a continuous flow from the nozzle and changes in actuation voltage polarity do not significantly affect the encapsulated fraction. These results help to guide current applications and future development of this microfluidic encapsulation technique for forming and loading unilamellar vesicles.
控制脂质体和囊泡的内容物对于它们在医学、生物技术和基础研究中的应用至关重要。蛋白质、DNA和RNA等货物在治疗应用以及细胞组织和功能的基础研究中越来越受到关注，但在囊泡内对生物分子进行可控封装和混合一直是一个挑战。最近，微流控封装已被证明能有效地将任意生物分子溶液加载到单层囊泡中。该方法利用压电驱动的液体射流使平面双层变形并形成囊泡，射流形成的流体涡旋将射流中的溶液与周围溶液混合。在这里，我们描述了通过微流控封装将混合物加载到单层囊泡中所使用的设备和方案，并且我们使用下落囊泡技术测量封装率为79±5%。此外，我们发现来自喷嘴的连续流的存在以及驱动电压极性的变化不会显著影响封装率。这些结果有助于指导这种用于形成和加载单层囊泡的微流控封装技术的当前应用和未来发展。
