Reinforced vesicles withstand rigors of microfluidic electroporation

Living cells synthesize and utilize femtomole and picoliter amounts of material, and an important goal of analytical chemistry is to develop artificial interfaces to efficiently study substances on this scale. This could be achieved with a picoliter container that could be controllably loaded, transported, and unloaded, most desirably in a microfluidic environment. Phospholipid vesicles – surfactant multilayers that can form 10 μm spheres – have been studied for this purpose, but they suffer from fragility and high deformability, which have made them difficult to handle and have limited their application. We present an approach in which a gel is formed in vesicles shortly after they are created. Microfluidic mechanical testing of these vesicles shows that, in the absence of gel, vesicles are difficult to maintain in a trapped state, but the reinforced vesicles exhibit a wide window of pressures under which they can be trapped and manipulated. This improvement is likely to be an essential feature of practical applications of vesicles as microfluidic cargo containers.