Surface immobilization of poly(ethyleneimine) and plasmid DNA on electrospun poly(L-lactic acid) fibrous mats using a layer-by-layer approach for gene delivery.

The method of coating electrospun ultrafine poly(L-lactic acid) fibers with DNA, by building up polyelectrolyte layer(s) of poly(ethyleneimine) (PEI) and plasmid DNA using an electrostatic layer-by-layer deposition method, for gene delivery is presented. The pGL3 encoding luciferase was applied as plasmid DNA. The quantity of pGL3 immobilized on individual fibers increased with increasing pGL3 concentration in the immersion solution (0.017-0.870 mg/mL) and increasing bilayer number of PEI/pGL3 (single-triple). With the exception of one specimen prepared under the condition 0.870 mg/mL pGL3 solution and double PEI/pGL3 layers, the transfection efficiency of COS-7 cells, defined by the ratio of fluorescence intensity (resulting from the presence of luciferase) with respect to the quantity of cellular protein on the fibrous mat increased with increasing quantity of pGL3 on the fibers. In addition to the ease of controlling the quality of polyelectrolyte bilayer(s) by simply changing the concentrations of substances and number of immersing cycles, the features of the electrospun fibrous mat such as a very large surface-to-volume ratio and flexibility, could potentially be employed as a strategy for gene therapy combined with tissue engineering technology.