Spectral study of some fatty acid-cholesterol mixtures

ABSTRACT This paper analyses the behavior of fatty acid-cholesterol mixtures, components of biological membranes, under theinfluence of the electromagnetic field.The mixtures acid lauric-cholesterol, prepared in thin layers of 24 .tm, have a liquid crystal behavior at room temperature.Spectra obtained in the range (330 ÷ 800) nm put into evidence some regions of resonance between the oscillatory systemcharacterising the textures and the electromagnetic field.The results are discussed in terms of Maxwell's formalism. A good agreement between experiment and theory was obtained for the launc acid. The impurification with cholesterol leads to a greater disorder in the system and the agreement with the theory is no more satisfactory. Keywords: biological membrane, fatty acid - cholesterol mixture, transmissivity, effective dielectric constant. 1. INTRODUCTIONBased on structure, properties and functional similarities, the great number of chemical different macromoleculesthat build living systems is devided into some main classes: proteins, glucids, fatty acids, nucleic acids. A mainrole in the understanding of the organization and functions of living systems is played by cellular membranes.Depending on the place and role they have, cellular membranes are strictly specialised 2