Interaction of chromium(III) complexes with model lipid bilayers: Implications on cellular uptake

Abstract

To understand molecular cytotoxicity of chromium(III) and how it affects the stability of biological membranes, studies on the interaction of chromium(III) complexes aquapentaminechromium complex (complex I) and trans- [Cr(5-methoxysalcyclohex) (H(2)O) (2)] ClO(4) (complex II) with model biomembranes have been carried out. Langmuir films of dimyristoylphosphatidylcholine (DMPC), dipalmitoylphosphatidic acid (DPPA), dioctadecyldimethylammoniumbromide (DOMA) at air/water interface interacting with the chromium(III) complexes have been characterized using the surface pressure-molecular area (π-A) isotherms. Initial surface pressures changes for the two complexes show that the chromium(III) complexes inserted in the Langmuir films and complex I interacted strongly compared to complex II. Supported bilayers (SB) of the lipids on solid substrates formed by hydrating their Langmuir-Blodgett films (LB films) have been characterized using linear dichroic spectra, low angle X-ray diffraction and steady state fluorescence anisotropy. Depending on the geometry of the ligands and concentration, the complexes either insert in the alkyl or in the head group region of the SB and sometimes in both regions. The Supported lipid bilayers are well-layered and at low concentration, the metal complexes are incorporated near the head group region. Order and increase in lamellar spacing show stronger interaction of complex I with the lipids compared with complex II. This study provides some insights into the mechanism of chromium(III) toxicity and uptake of chromium(III) by the cells.

Testing the limits of model membrane simulations—bilayer composition and pressure scaling

“…The model is built with predefined area per lipid А = 0.40 nm 2 resulting in total membrane surface area of 32.40 nm 2 . This initial area/lipid assigned to DPPC is estimated for temperature 310 K from theoretical treatment of lipid van der Waals surfaces in mixed bilayers, also including the so‐called “free area.” This value of the area coincides with the one determined for living cells and experimentally measured for lipid/cholesterol mixtures . Hence, we have chosen to adopt this value even though cholesterol is not present explicitly in the models as the aim is to carry out the simulations at conditions as close as possible to those in the organism and to reproduce the phase state (dense, ordered) of neoplastic cell membranes.…”

The role of Chromium III in the organism and its possible use in diabetes and obesity treatment

“…In addition, these authors showed no effect of chromium ions on the phosphorylation of the insulin signal transduction proteins: IR-beta, IRS, PI 3-K and Akt-1. Results a study Raja et al showed the ability of Cr to interact and modify the structure of lipid bilayers [59].…”

Enhanced Photoinduced Electron Transfer at the Surface of Charged Lipid Bilayers

“…The electrostatic interactions between cationic species and anionic liposomes are strong enough to lead to adsorption of molecules onto lipid membranes. [34][35][36][37][38][39][40] In this work, we used this interaction to self-assemble the different components of a photocatalytic system on a well-defined nanostructure, namely, phospholipid vesicles bearing a positive or negative charge density. The adsorption of a charged dye onto the surface of a charged liposome, and the subsequent electron transfer to an electron acceptor (EA) that in the reduced form might be repelled from the liposome surface has been investigated.…”