title: Measurement of single low-density lipoprotein particles by atomic force microscopy.
abstract: BACKGROUND
  The size of lipoprotein particles is relevant to the risk of coronary artery disease (CAD).
  
  
  METHODS
  We investigated the feasibility of atomic force microscopy (AFM) for evaluating the size of large low-density lipoprotein (LDL) and small dense LDL (sd-LDL) separated by ultracentrifugation. The measurements by AFM in tapping mode were compared to those by electron microscopy (EM).
  
  
  RESULTS
  There was a significant difference in particle sizes determined by AFM between large LDL (20.6 ± 1.9 nm, mean ± SD) and sd-LDL (16.2 ± 1.4 nm) obtained from six healthy volunteers (P < 0.05). The particle sizes determined by EM for the same samples were 23.2 ± 1.4 nm for large LDL and 20.4 ± 1.4 nm for sd-LDL. The difference between large LDL and sd-LDL detected by EM was also statistically significant (P < 0.05). In addition, the particle sizes of each lipoprotein fraction were significantly different between AFM and EM: P < 0.05 for large LDL and P < 0.05 for sd-LDL.
  
  
  CONCLUSIONS
  AFM can differentiate between sd-LDL and large LDL particles by their size, and might be useful for evaluating risk for CAD.
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Sakurai
authors.forename: Seiji
authors.initials: S
authors.lastname: Takeda
authors.forename: Jun-ya
authors.initials: JY
authors.lastname: Takahashi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Norio
authors.initials: N
authors.lastname: Wada
authors.forename: Suchin
authors.initials: S
authors.lastname: Trirongjitmoah
authors.forename: Takeshi
authors.initials: T
authors.lastname: Namita
authors.forename: Shigeki
authors.initials: S
authors.lastname: Jin
authors.forename: Akiko
authors.initials: A
authors.lastname: Ikuta
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Furumaki
authors.forename: Shu-Ping
authors.initials: SP
authors.lastname: Hui
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Fuda
authors.forename: Masato
authors.initials: M
authors.lastname: Fujikawa
authors.forename: Koichi
authors.initials: K
authors.lastname: Shimizu
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Chiba
mesh_terms: D000328:Adult; D001774:Blood Chemical Analysis / Q000379:methods*; D005240:Feasibility Studies; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood* / Q000737:chemistry; D008297:Male; D018625:Microscopy, Atomic Force / Q000379:methods*; D010316:Particle Size; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D008077:Lipoproteins, LDL
keywords: AFM; electron microscopy; large LDL; small dense LDL