ABSTRACT
Membranes separate cells and cell organelles from the outside world and allow for the creation and maintenance of chemically different environments. However, at the same time cells need to communicate with the outside world. For communication, exchange of materials is required. Although proteins control most of this exchange, some molecules are transported passively through the lipid membrane. This chapter describes several methods to explore and quantify the passive permeability of membranes using giant unilamellar vesicles as model systems.
