Application of Kelvin force microscopy for evaluation of oxidized low-density lipoprotein

Investigation of the properties of oxidized low-density lipoprotein is important because it is a risk factor of cardiovascular disease development. Low-density lipoprotein is known to have a positive charge on the surface attributable to amino groups of lysine moieties. Its positive charge can be decreased by oxidation. For this study, the topography and surface potential of LDL and ox-LDL were measured using atomic force microscopy and Kelvin probe force microscopy. The Kelvin probe force microscopy images of ox-LDL differ from those obtained using n-LDL. We demonstrated a method to evaluate the oxidation level of LDL using AFM and KPFM.