Detecting LDL-oxidation process using Langmuir monolayer technique

• Langmuir monolayer technique is used to monitor LDL oxidation.
• Oxidized LDL is a surface active macromolecule.
• Copper ions can oxidize LDL while BSA inhibits this oxidation.
• LDL Oxidation depends strongly on Cu2+/BSA molar ratio and incubator temperature.

We introduced a novel method to detect the low density lipoprotein (LDL) oxidation process by transition metals using the Langmuir monolayer technique. This process has been studied because of its potential relevance to pathological processes like atherosclerosis. In particular, we investigated the influence of copper ions on the oxidation susceptibility of the LDL and the ability of bovine serum albumin (BSA) to inhibit this oxidation. Langmuir monolayer and Wilhelmy techniques have been successfully used to achieve these aims. In additions, our results agree qualitatively with the other conventional methods which detect LDL-oxidation. Our results indicate that the oxidation of LDL depends strongly on the ratio between Cu2+ and BSA. Moreover, the BSA–Cu2+ binding affinity may play an important role in the oxidation process of the LDL particles. Our study showed that BSA is an effective radical trap as evidenced by its ability to prevent LDL oxidation induced by Cu2+. These simple in vitro experiments of the Langmuir monolayer technique may serve as an elementary tool in clinical tests or pharmaceutical applications.

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