The integration of IR-spectroscopy and Atomic Force Microscopy (AFM) in the technique of Nano-IR circumvents the Abbe diffraction limit that restricts the resolution of other commonly used vibrational spectroscopies and permits chemical characterisation of biological surfaces at previously unattainable spatial resolution. Using this relatively new technique in conjunction with surface specific SFG spectroscopy has enabled the molecular compositions, structures and conformations of surface films to be investigated at nanometre spatial resolution. In this work these complementary techniques have been applied to Red Blood Cells (RBCs) from patients with Sickle Cell Disease (SCD) to elucidate the effects of oxidative stress on the cell lipid bilayer membrane. The HbS mutated form of Haemoglobin present in RBCs of SCD patients polymerises when de-oxygenated causing deformation of the cell from the well-known biconcave disc to sickled morphologies. In this form the cells are found to be in great abundance in sites of cell occlusion which is explained by their observed change in adhesive properties. It has been proposed that oxidative damage to the cell membrane contributes to these adhesive changes and hence to the pathogenesis of SCD. In this work surface-localised enhancement of the C-O(H) vibrational band as well as significant lipid bilayer disordering was found for the RBCs. To elucidate the fundamental changes causing such observations the effect of oxidative stress on a supported lipid bilayer model membrane was investigated. Our two-pronged approach leads to a proposed mechanism for membrane damage under oxidative stress. The analytical techniques used in this study promise to be effective tools for assessing the efficacy of novel antioxidants and antioxidant regimes which will inform their rational use for amelioration of the clinical signs of SCD.