Changes in Elastic and Morphological Properties of Erythrocyte Cells by Methylene Blue-Mediated Photo-Oxidation

Erythrocytes are vital cells responsible for transporting oxygen through hemoglobin. Its flexible structure and morphology allow it to pass through narrow capillaries in the body, ensuring its homeostasis. Therefore, the study of their responses under oxidative stress is crucial to understand the morphological and mechanical changes that erythrocytes can undergo. Photosensitizing molecules are capable of triggering the formation of reactive oxygen species (ROS) in the presence of light, especially singlet oxygen. The selection of molecules Methylene Blue (MB), Dimethylmethylene Blue (DMB), and some porphyrins such as CisDiMPyP, which are presented in increasing order of hydrophobicity, is due to the contrast of the site of generation of reactive species and high capacity of generate singlet oxygen from them. By directing attention to photosensitive molecules with different partitions, we are not only changing the singlet oxygen target but also selecting the oxidation mechanism involved, as the type I mechanism depends on contact with the membrane due to its electron transfer nature. This should influence in different ways the level of denaturation of cytoskeletal proteins in relation to the oxidation of erythrocyte membrane lipids. As the central focus is established on the investigation of morphological and mechanical changes in erythrocytes due to oxidation, we used an aspiration approach using micropipettes coupled with optical microscopy to assess their elasticity. While its morphology will be studied through atomic force microscopy (AFM) which will also be used to evaluate the denaturation of cytoskeletal proteins obtained through erythrocyte ghosts.