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Updated: May 15, 2026

Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol
Published on: March 25, 2020
Relaxivities of magnetoliposomes: the effect of cholesterol
Alexandra Carvalho1, M Clara Gonçalves, M Bárbara F Martins
1CENIMAT-I3N/DCM/FCT/UNL, Campus da Caparica, 2829-516 Caparica, Portugal. amfc.carvalho@fct.unl.pt
Abstract:
We present relaxivities measurements for both the longitudinal and transverse relaxations of two types of liposomes loaded with ultra small superparamagnetic iron oxide nanoparticles. The magnetoliposome systems presented are soybean phosphatidylcholine liposomes, with and without cholesterol, in the phospholipid bilayer with different molar ratios lipid:cholesterol. In fact, cholesterol is needed to obtain stable liposomes for intravenous administration. The longitudinal and transverse relaxivities were measured with a NMR spectrometer in a 7T magnetic field. For the studied concentrations, the liposomes show a negligible effect on the longitudinal relaxation time T1 of the medium, but they are very efficient on decreasing the transverse relaxation time T2, the behaviour one expects for a negative CA. We observed a lower transverse relaxivity for the magnetoliposome nanosystem with cholesterol, which strongly decreases with the cholesterol content in the liposome bilayer.
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