title: Use of inert gas jets to measure the forces required for mechanical gene transfection.
abstract: BACKGROUND
  Transferring genes and drugs into cells is central to how we now study, identify and treat diseases. Several non-viral gene therapy methods that rely on the mechanical disruption of the plasma membrane have been proposed, but the success of these methods has been limited due to a lack of understanding of the mechanical parameters that lead to cell membrane permeability.
  
  
  METHODS
  We use a simple jet of inert gas to induce local transfection of plasmid DNA both in vitro (HeLa cells) and in vivo (chicken chorioallantoic membrane). Five different capillary tube inner diameters and three different gases were used to treat the cells to understand the dependency of transfection efficiency on the dynamic parameters.
  
  
  RESULTS
  The simple setup has the advantage of allowing us to calculate the forces acting on cells during transfection. We found permeabilization efficiency was related to the dynamic pressure of the jet. The range of dynamic pressures that led to transfection in HeLa cells was small (200 ± 20 Pa) above which cell stripping occurred. We determined that the temporary pores allow the passage of dextran up to 40 kDa and reclose in less than 5 seconds after treatment. The optimized parameters were also successfully tested in vivo using the chorioallantoic membrane of the chick embryo.
  
  
  CONCLUSIONS
  The results show that the number of cells transfected with the plasmid scales with the dynamic pressure of the jet. Our results show that mechanical methods have a very small window in which cells are permeabilized without injury (200 to 290 Pa). This simple apparatus helps define the forces needed for physical cell transfection methods.
authors.affiliation: Chemical Engineering Department, McGill University, 3610 rue University, Montréal, H3A 2B2, Canada.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Chouinard-Pelletier
authors.forename: Mathieu
authors.initials: M
authors.lastname: Leduc
authors.forename: David
authors.initials: D
authors.lastname: Guay
authors.forename: Sylvain
authors.initials: S
authors.lastname: Coulombe
authors.forename: Richard L
authors.initials: RL
authors.lastname: Leask
authors.forename: Elizabeth A V
authors.initials: EA
authors.lastname: Jones
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D016923:Cell Death; D002463:Cell Membrane Permeability; D049033:Chorioallantoic Membrane / Q000378:metabolism; D005898:Glass; D006367:HeLa Cells; D006801:Humans; D055595:Mechanical Phenomena; D005741:Noble Gases; D014162:Transfection / Q000295:instrumentation*
chemical_list: D005741:Noble Gases