Medicinski vjesnik, Vol. 22 No. (3), 1990.
Original scientific paper
Lipozomes as a model system in biomineralization research
Drago Škrtić
Edward D. Eanes
Abstract
Artificial lipid vesicles, liposomes, are used as a model for examining membrane-mediated calcium phosphate mineralization. Applying different procedures and techniques, the kinetics of mineral formation are followed in aqueous suspension of anionic liposomes containing high levels of cholesterol, different phospholipid — cholesterol compositions and model liposomes with matrix vesicle-like compositions. Results of the study show that membrane lipid constituents can affect calcium phosphate precipitation in liposome suspensions at least in 3 ways: (1) by controlling transmembrane transport of calcium ions, (2) by delaying the release of intraliposomally formed seed crystals into the external medium and (3) by inhibiting further growth of seed crystals once they come into contact with the external solution. With 50 mM encapsulated phosphate and in the presence of ionophore, cholesterol significantly affected the mineralization kinetics. Inhibition of ionophore-mediated intraliposomal mineral formation could be related to the inflexible cholesterol molecules making the liposomal membrane more rigid. Interference of cholesterol with the membrane transport processes necessary for endogenous precipitation in liposomes containing different anionic components is not compromised by the specificic phospholipid incorporated in the membrane.
Keywords
biomineralization; calcium phosphates; cholesterol; liposomes; matrix vesicles
Hrčak ID:
196249
URI
Publication date:
1.12.1990.
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