We report the design and characterization of thin polymer-based coatings that promote the contact transfer of DNA to soft surfaces under mild and physiologically relevant conditions. Past studies reveal polymer multilayers fabricated using linear poly(ethylene imine) (LPEI), poly(acrylic acid) (PAA), and plasmid DNA promote contact transfer of DNA to vascular tissue. Here, we demonstrate that changes in the structure of the polyamine building blocks of these materials can have substantial impacts on rates and extents of contact transfer. We used two hydrogel-based substrate models that permit identification and manipulation of parameters that influence contact transfer. We used a planar gel model to characterize films having the structure (cationic polymer/PAA/cationic polymer/plasmid DNA)x fabricated using either LPEI or one of three poly(β-amino ester)s as polyamine building blocks. The structure of the polyamine influenced subsequent contact transfer of DNA significantly; in general, films fabricated using more hydrophilic polymers promoted transfer more effectively. This planar model also permitted characterization of the stabilities of films transferred onto secondary surfaces, revealing rates of DNA release to be slower than rates of release prior to transfer. We also used a three-dimensional hole-based hydrogel model to evaluate contact transfer of DNA from the surfaces of inflatable catheter balloons used in vascular interventions and selected a rapid-transfer coating for proof-of-concept studies to characterize balloon-mediated contact transfer of DNA to peripheral arterial tissue in swine. Our results reveal robust and largely circumferential transfer of DNA to the luminal walls of peripheral arteries using inflation times as short as 15 to 30 s. The materials and approaches reported here provide new and useful tools for promoting rapid, substrate-mediated contact transfer of plasmid DNA to soft surfaces in vitro and in vivo that could prove useful in a range of fundamental and applied contexts.
Keywords: DNA; coatings; contact transfer; polymers; thin films.