title: [Synthesis and screening of polyethylenimine as a carrier for gene transfer into cultured human tumor cells].
abstract: OBJECTIVE
  Choosing suitable gene carrier is very important in gene therapy. Recently, polyethylenimine (PEI), a new polycation compound, is particularly attractive due to its high transduction efficiency and low toxicity. This study was to synthesize a series of PEI nanogels of different particle diameters by photochemistry, investigate the relation between the transfection efficiency and particle diameter, and screen ideal gene carrier.
  
  
  METHODS
  PEI nanogels were synthesized by photochemistry. The particle diameter was detected by photo correlation spectroscopy (PCS). The spherical morphology of the nanogels was characterized by scanning electron microscopy (SEM), and confirmed by atomic force microscopy (AFM). Using PEI/DNA complex as a plasmid vector, the enhanced green fluorescence protein (EGFP) gene was transferred into Bel7402 and A549 cells. Gene expression was quantitatively evaluated by fluorescent microscopy and flow cytometry (FCM).
  
  
  RESULTS
  The diameter of synthesized PEI nanogels was in the range of 80-200 nm, and most of them were globular. The delivery rate reached the maximum when using 4 microg PEI (86.9 nm) to transfer 2 microg EGFP: the delivery rates were (32.75+/-1.01)% for Bel7402 cells and (29.81+/-1.84)% for A549 cells when detected by fluorescent microscopy, and were (32.40+/-1.41)% for Bel7402 cells and (30.00+/-1.86)% for A549 cell when detected by FCM. There was no significant difference between PEI and LipofectamineTM 2000 in the transfection efficiency (P > 0.05).
  
  
  CONCLUSIONS
  PEI nanogels synthesized by photochemistry are effective nonviral vectors for gene delivery into human tumor cells in vitro. The transfection efficiency of 86.9 nm PEI is the highest.
authors.affiliation: Institute of Cancer Research, Xuzhou Medical College, Xuzhou, Jiangsu, 221006, P. R. China. yyhxzsn@yahoo.com.cn
authors.forename: Yuan-Hu
authors.initials: YH
authors.lastname: Yao
authors.forename: Yong-Biao
authors.initials: YB
authors.lastname: Liu
authors.forename: Yong
authors.initials: Y
authors.lastname: Feng
authors.forename: Xia
authors.initials: X
authors.lastname: Feng
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Xu
authors.forename: Si-De
authors.initials: SD
authors.lastname: Yao
mesh_terms: D045744:Cell Line, Tumor; D004337:Drug Carriers; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins / Q000378:metabolism*; D006801:Humans; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D000080385:Nanogels; D010316:Particle Size; D010957:Plasmids; D011092:Polyethylene Glycols; D011094:Polyethyleneimine / Q000138:chemical synthesis* / Q000737:chemistry*; D014162:Transfection
chemical_list: D004337:Drug Carriers; D000080385:Nanogels; C485184:enhanced green fluorescent protein; C413692:polyethylene glycol polyethyleneimine nanogel; D049452:Green Fluorescent Proteins; D011092:Polyethylene Glycols; D011094:Polyethyleneimine