Sizing of giant unilamellar vesicles using a metal mesh with a high opening ratio

Size control of giant unilamellar vesicles (GUVs) has been challenged extensively for realizing quantitative assays within these biomimetic reactors. Although microfluidics-based monodisperse GUV generation methods have shown tremendous progress, they are often difficult and still not available for general users. Meanwhile, the conventional bulk methods, which are more flexible in compositions, only generate polydisperse GUVs with a linear dimension ranging more than two orders of magnitude. Here, we characterized the sizing protocol of GUVs using the metal mesh with a large opening area ratio (>35%). Unlike the conventional track-etched membrane filters with a small opening area ratio (<10%), the present method enabled fast filtration (<10 min) to remove GUVs smaller than the mesh size without delicate flow control. We demonstrated that the combination of extrusion and filtration with selected filters produced GUV populations with fairly narrow size distributions (<30% C.V. in diameter).