Liposomes are extensively used to study the interaction of proteins, peptides and other molecules with the surface of a lipid membrane. One of the parameters that affects this interaction is the charge of the liposomal membrane. Liposomes are always made in aqueous environment and they are sized to the desired size in liquid state using various methods such as high-pressure extrusion through nano sized pore track etch membranes. Liposome without water is meaningless. In rare occasions, liposomes are freeze dried and proliposomes are formed in the presence of a lyoprotectant such as trehalose. Using a lyoprotectant is necessary in order to maintain the size of the liposomes after rehydration.

Phosphatidylserine (PS) is a negatively charged molecule. The amount of the negative zeta potential in the liposomes depends on the molar percentage of the phosphatidylserine (PS) in the formulation. Anionic Lyophosome™-Phosphatidylserine (PS) catalog contains products made from 0.5 up to 90 percent DOPS with various amount of negative zeta potentials. The matrix lipid, DOPC, that is used in the formulations does not significantly contribute to the charge of the liposomes. Anionic liposomes are used in blood complement studies and various types of in vitro studies.

Lyophosome™ product catalog is composed of a large selection of freeze-dried liposomes with various types of lipids and wide range of zeta potentials and different properties. Lyophosome™ products should be used by scientists who understand liposome formulation and have the proper equipment to check the size, separate non-encapsulated drugs and do the proper assays. Freeze-dried liposomes cannot be used blindly.