Method for efficient pelleting of small unilamellar model membrane vesicles

Separation of model membrane vesicles from external solution is an important step in quantitation of vesicle-associated materials. Ordinarily, such experiments cannot be done with small unilamellar vesicles because they are too small to be pelleted by centrifugation. A method is described that overcomes this difficulty by use of brominated phospholipids. It is shown that efficient pelleting of small unilamellar vesicles (greater than 98%) can be obtained by ultracentrifugation.