title: An efficient calcium phosphate nanoparticle-based nonviral vector for gene delivery.
abstract: BACKGROUND
  Smaller nanoparticles facilitate the delivery of DNA into cells through endocytosis and improve transfection efficiency. The aim of this study was to determine whether protamine sulfate-coated calcium phosphate (PS-CaP) could stabilize particle size and enhance transfection efficiency.
  
  
  METHODS
  pEGFP-C1 green fluorescence protein was employed as an indicator of transfection efficiency. Atomic force microscopy was used to evaluate the morphology and the size of the particles, and an MTT assay was introduced to detect cell viability and inhibition. The classical calcium phosphate method was used as the control.
  
  
  RESULTS
  Atomic force microscopy images showed that the PS-CaP were much smaller than classical calcium phosphate particles. In 293 FT, HEK 293, and NIH 3T3 cells, the transfection efficiency of PS-CaP was higher than for the classical calcium phosphate particles. The difference in efficiencies implies that the smaller nanoparticles may promote the delivery of DNA into cells through endocytosis and could improve transfection efficiency. In addition, PS-CaP could be used to transfect HEK 293 cells after one week of storage at 4°C with a lesser extent of efficiency loss compared with classical calcium phosphate, indicating that protamine sulfate may increase the stability of calcium phosphate nanoparticles. The cell viability inhibition assay indicated that both nanoparticles show similar low cell toxicity.
  
  
  CONCLUSIONS
  PS-CaP can be used as a better nonviral transfection vector compared with classical calcium phosphate.
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology, Ministry of Education of China, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China.
authors.forename: Yachun
authors.initials: Y
authors.lastname: Liu
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Fangli
authors.initials: F
authors.lastname: He
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.forename: Dexi
authors.initials: D
authors.lastname: Zhang
authors.forename: Shuanglin
authors.initials: S
authors.lastname: Xiang
authors.forename: Shengpei
authors.initials: S
authors.lastname: Su
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry*; D002470:Cell Survival / Q000187:drug effects; D004355:Drug Stability; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins / Q000737:chemistry; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D018625:Microscopy, Atomic Force; D041681:NIH 3T3 Cells; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D010316:Particle Size; D011479:Protamines / Q000737:chemistry* / Q000494:pharmacology; D014162:Transfection / Q000295:instrumentation / Q000379:methods*
chemical_list: D002130:Calcium Phosphates; D011479:Protamines; D049452:Green Fluorescent Proteins; C020243:calcium phosphate