Biophysical Studies on the Effect of Gamma Rays on Liposomes

Document Type : Original Article

Authors

1 FACULTY OF SCIENCE- CAIRO UNIVERSITY

2 department of physics, faculty of science, Al azhar university, Cairo, Egypt

3 Physics department , Faculty of science, Al azhar University

4 Biophysics Dpt., Faculty of Science , Cairo University

5 Physics department, Faculty of Science , AlAzhar University

Abstract

Liposomes are vesicular structures made of lipids that are formed in aqueous solutions, which can be used as models to study the cell membrane. In the present study the effects of gamma (γ) rays on dipalmitoylphosphatidylcholine (DPPC) liposomes were studied by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, as well as dynamic light scattering (DLS) and viscosity measurements. The DPPC liposomes were exposed to three different doses 40, 80, and 120Gy which emitted from 60Co gamma rays source with a dose rate of 9 kGy/h. The DLS measurements confirmed the monodispersity of all samples. TEM results revealed that there is a change in morphology and size of liposomes, which is in a good agreement with the increase in viscosity measurements. FTIR measurements showed significant changes in the characteristics bands of DPPC liposomes confirming the effect of γ-rays on the main groups such as CH2 bending vibrations and the symmetric and antisymmetric PO2- stretching vibrations at 1090 and 1220 cm-1 respectively. In addition to the shifting of the OH stretching vibrations from 3439 cm-1 to 3453 cm-1due to the 120 Gy exposure. The spectral changes seem to be due to some sort of water loss and molecular conformational changes due to ionization and formation of free radicals which affect the head groups of the DPPC liposomes leading to lipid lateral diffusion enhancing the fusion of small vesicles to form larger structures.

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