title: Effect of size and serum proteins on transfection efficiency of poly ((2-dimethylamino)ethyl methacrylate)-plasmid nanoparticles.
abstract: OBJECTIVE
  The aim of this study was to gain insight into the relation between the physical characteristics of particles formed by a plasmid and a synthetic cationic polymer (poly(2-dimethylamino)ethyl methacrylate, PDMAEMA) and their transfection efficiency.
  
  
  METHODS
  The PDMAEMA-plasmid particles were characterized by dynamic light scattering (size) and electrophoretic mobility measurements (charge). The transfection efficiency was evaluated in cell culture (COS-7 cells) using a pCMV-lacZ plasmid coding for beta-galactosidase as a reporter gene.
  
  
  RESULTS
  It was shown that the optimal transfection efficiency was found at a PDMAEMA-plasmid ratio of 3 (w/w), yielding stable and rather homogeneous particles (diameter 0.15 micron) with a narrow size distribution and a slightly positive charge. Particles prepared at lower weight ratios, showed a reduced transfection efficiency and were unstable in time as demonstrated by DLS measurements. Like other cationic polymers, PDMAEMA is slightly cytotoxic. This activity was partially masked by complexing the polymer with DNA. Interestingly, the transfection efficiency of the particles was not affected by the presence of serum proteins.
  
  
  CONCLUSIONS
  PDMAEMA is an interesting vector for the design of in vivo and ex vivo gene transfection systems.
authors.affiliation: Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), The Netherlands.
authors.forename: J Y
authors.initials: JY
authors.lastname: Cherng
authors.forename: P
authors.initials: P
authors.lastname: van de Wetering
authors.forename: H
authors.initials: H
authors.lastname: Talsma
authors.forename: D J
authors.initials: DJ
authors.lastname: Crommelin
authors.forename: W E
authors.initials: WE
authors.lastname: Hennink
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D019556:COS Cells / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D004560:Electricity; D015870:Gene Expression / Q000187:drug effects; D046911:Macromolecular Substances; D010316:Particle Size; D010957:Plasmids / Q000235:genetics / Q000378:metabolism*; D011109:Polymethacrylic Acids / Q000378:metabolism* / Q000633:toxicity; D014162:Transfection
chemical_list: D001798:Blood Proteins; D046911:Macromolecular Substances; D011109:Polymethacrylic Acids