title: [Interaction between functional nano-hydroxyapatite and cells and the underlying mechanisms].
abstract: OBJECTIVE
  To explore the interaction between arginine functionalized hydroxyapatite (HAP/Arg) nanoparticles and endothelial cells, and to investigate mechanisms for endocytosis kinetics and endocytosis.
  
  
  METHODS
  Human umbilical vein endothelial cells (HUVECs) were selected as the research model.Cellular uptake of HAP/Arg nanoparticles were observed by laser scanning confocal microscopy.Average fluorescence intensity of cells after ingestion with different concentrations of HAP/Arg nanoparticles were determined by flow cytometer and atomic force microscopy.
  
  
  RESULTS
  The HAP/Arg nanoparticles with doped terbium existed in cytoplasm, and most of them distributed around the nucleus area after cellular uptake by HUVECs. Cellular uptake process of HAP/Arg nanoparticles in HUVECs was in a time and concentration dependent manner. 4 h and 50 mg/L was the best condition for uptake. HAP/Arg nanoparticles were easier to be up-taken into the cells than HAP nanoparticles without arginine functionalized.
  
  
  CONCLUSIONS
  HAP/Arg nanoparticles are internalized by HUVECs cells through an active transport and energy-dependent endocytosis process, and it is up-taken by cells mainly through caveolin-mediated endocytosis, but the clathrin-dependent endocytic pathway is also involved..
authors.affiliation: Medical Experimental Center, Third Xiangya Hospital, Central South University, Changsha 410013, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.affiliation: Medical Experimental Center, Third Xiangya Hospital; Research Center for Medical Material and Instruments, Central South University, Changsha 410013, China.
authors.forename: Yanzhong
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Medical Experimental Center, Third Xiangya Hospital, Central South University, Changsha 410013, China.
authors.forename: Guohui
authors.initials: G
authors.lastname: Wang
authors.affiliation: Medical Experimental Center, Third Xiangya Hospital, Central South University, Changsha 410013, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Tan
authors.affiliation: Medical Experimental Center, Third Xiangya Hospital; Research Center for Medical Material and Instruments, Central South University, Changsha 410013, China.
authors.forename: Shaihong
authors.initials: S
authors.lastname: Zhu
mesh_terms: D001120:Arginine / Q000494:pharmacology; D001693:Biological Transport, Active / Q000502:physiology; D022461:Caveolins / Q000502:physiology; D002478:Cells, Cultured; D002966:Clathrin / Q000502:physiology; D017886:Durapatite / Q000493:pharmacokinetics*; D004705:Endocytosis / Q000502:physiology*; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology*; D006801:Humans; D053758:Nanoparticles / Q000378:metabolism
chemical_list: D022461:Caveolins; D002966:Clathrin; D017886:Durapatite; D001120:Arginine