Formation and properties of thin‐walled phospholipid vesicles

TLDR

Thin‑walled phospholipid vesicles (0.5–10 µm) form when a hydrated lipid film swells slowly in water or nonelectrolyte solutions. Centrifugation and resuspension transfer vesicles between media, and immersion refractometry estimates their internal osmolarity. Electron microscopy and lipid analysis show that vesicle walls are one or a few bilayers, and the internal osmolarity scales linearly with the external medium.

Abstract

Abstract Large numbers of thin‐walled vesicles, 0.5 to 10 μ in diameter, can be formed by permitting a thinly spread layer of hydrated phospholipids to swell slowly in distilled water or an aqueous solution of nonelectrolytes. Electron micrographs and phospholipid analyses indicate that the walls consist of a single or a few bilayers. The vesicles can be centrifuged and resuspended in another medium, making them a useful system for studying permeability. The osmolarity of the solution in the interior of the vesicles can be estimated by immersion refractometry. The osmolarity of the internal aqueous phase is linearly related to the osmolarity of the external medium.