Rational design of nanoliposomes by tuning their bilayer rigidity for the controlled release of oxygen

Abstract

The addition of cholesterol and polymers to the phospholipid envelope of liposomes increases the rigidity of those liposomes, affecting the sustained release of any encapsulated drug. In the present study, to control the oxygen concentration in cells or tissue, oxygen-dissolved nanoliposomes (ODLs) consisting of a phospholipid envelope and an oxygen core were produced. To control the oxygen release rate, the bilayer rigidity was increased by adding cholesterol and a polymer to the phospholipid envelope of the ODLs. Using cryo-transmission electron microscopy and small-angle x-ray scattering, we confirmed the size of the ODLs and the thickness of the bilayered shell following the addition of the cholesterol and polymer. The effect of the increase in the envelope thickness and stiffness on the oxygen release rate was determined using a dissolved oxygen meter. The ODLs were not cytotoxic for HeLa or human dermal fibroblast cells at the tested concentrations, and beneficial changes to their oxygen release rate were observed. Overall, it was found that ODLs with low cytotoxicity and tunable phospholipid envelope components have significant potential as controlled-release carriers of oxygen. (c) 2022 Elsevier B.V. All rights reserved.