Analysis of DNA mobility and gene electrotransfer in 3D in vitro collagen gel model

Abstract

Background: Gene electrotransfer is an established method that enables transfer of DNA into cells with electric pulses. Several studies analyzed different parameters; however the question of the mechanisms involved in gene electrotransfer remains open. One of main obstacles toward efficient gene electrotransfer in vivo is relatively poor DNA mobility in tissues.Objective and method: In order to analyze the effect of impaired mobility on gene electrotransfer efficiency, we applied electric pulses with different durations on plated cells, cells grown on collagen layer and cells embedded in collagen gel (3D model) and compared gene electrotransfer efficiency and viability of cells.Results: We obtained the highest transfection of plated cells, while transfection efficiency of embedded cells in 3D model was lowest and similar as in in vivo. To further analyze poor DNA mobility in 3D model, we applied DNA in top of or injected it into 3D model and showed that former way increases gene electrotransfer efficiency as was shown in in vivo studies.Conclusion: We reported empirically and theoretically evidence that DNA has impaired mobility and diffusion in collagen environment. In addition our method provides resembling in vivo situation, where gene electrotransfer mechanisms can be studied.