Fluid bioreactors in microgravity environments may utilize alternative methods of containment and mixing. The ring-sheared drop (RSD) is a containerless mixing device which functions in microgravity using surface tension for containment and mixes through interfacially-driven flow. To assess the feasibility of using interfacially driven flow devices, such as the RSD, as bioreactors, Escherichia coli growth and recombinant protein expression were analyzed in a ground-based analog of the RSD called the knife edge surface viscometer (KEV). Results demonstrated that the KEV can facilitate the growth of E. coli and that growth rate increases logarithmically with increasing knife edge rotation rate, similar to the standard growth method on Earth (orbital shaker). Furthermore, the KEV was shown to be viable for supporting recombinant protein expression in E. coli at levels comparable to those achieved using standard growth methods.

在微重力环境中的流体生物反应器可以利用封闭和混合的替代方法。环形剪切滴（RSD）是一种无容器的混合设备，它利用表面张力进行密闭并在微重力下起作用，并通过界面驱动的流进行混合。为了评估使用界面驱动流动设备（例如RSD）作为生物反应器的可行性，在RSD的地面类似物称为刀刃表面粘度计（KEV）中分析了大肠杆菌的生长和重组蛋白表达。结果表明，KEV可以促进大肠杆菌的生长并且该增长速度随刀刃旋转速度的增加呈对数增长，类似于地球上的标准生长方法（定轨摇床）。此外，已证明KEV在支持重组蛋白在大肠杆菌中的表达方面与使用标准生长方法所达到的水平相当，是可行的。