Optical transport of a single cell-sized liposome

A closed phospholipid membrane vesicle, or giant liposome, with a diameter of ∼10 μm, constitutes a model of a living cell. Since the phospholipid membrane is about 5 nm thick, it is extremely difficult to trap an individual giant liposome with a laser. We report here the intact transport of an individual cell-sized liposome using an infrared laser. It is shown that the optical attractive potential on a liposome with an inner solution of higher refractivity is about one order of magnitude greater than that of a liposome with the same solution both inside and outside. Since this cell-sized liposome is rather stable, the optical manipulation of liposomes could be useful for the realization of a μm-scaled laboratory for use in biochemistry and molecular biology.