title: Elastic modulus of low-density lipoprotein as potential indicator of its oxidation.
abstract: BACKGROUND
  Evaluation of low-density lipoprotein oxidation is important in the risk assessment of cardiovascular disease. Atomic force microscope is widely used to evaluate the physical properties including stiffness on a single-particle scale. In this study, the effect of low-density lipoprotein oxidation on the low-density lipoprotein stiffness was investigated using an atomic force microscope.
  
  
  METHODS
  Isolated low-density lipoprotein particles with or without oxidation were densely bound to an Au substrate on mica, and then pressed and deformed by the atomic force microscope tip. The stiffness of each low-density lipoprotein particle was estimated as the elastic modulus obtained by the force curve analysis. Biochemical change of low-density lipoprotein due to oxidation was studied by electrophoresis.
  
  
  CONCLUSIONS
  The elastic modulus of low-density lipoprotein particles ranged between 0.1 and 2 MPa. The oxidation of low-density lipoprotein increased the number of low-density lipoprotein particles with smaller elastic moduli, indicating the decrease in low-density lipoprotein stiffness. The elastic modulus of low-density lipoprotein might be potentially useful to evaluate low-density lipoprotein oxidation.
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Takeda
authors.affiliation: Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan.
authors.forename: Agus
authors.initials: A
authors.lastname: Subagyo
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan keino@hs.hokudai.ac.jp.
authors.forename: Shu-Ping
authors.initials: SP
authors.lastname: Hui
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Fuda
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Rojeet
authors.initials: R
authors.lastname: Shrestha
authors.affiliation: Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Sueoka
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Chiba
mesh_terms: D000328:Adult; D000538:Aluminum Silicates / Q000737:chemistry; D055119:Elastic Modulus; D005260:Female; D006046:Gold / Q000737:chemistry; D006801:Humans; D007700:Kinetics; D008077:Lipoproteins, LDL / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D018625:Microscopy, Atomic Force; D010084:Oxidation-Reduction
chemical_list: D000538:Aluminum Silicates; D008077:Lipoproteins, LDL; D006046:Gold; C011934:mica
keywords: AFM; bioanalytical methods; biological samples; lipids; nanoparticles