Gene delivery via DNA incorporation within a biomimetic apatite coating

Integrating inductivity with conductivity in a material may advance tissue engineering. An organic/inorganic hybrid was developed by incorporating plasmid DNA encoding for the beta-gal gene complexed with Lipofectamine 2000 (DNA-Lipoplex) within apatite via coprecipitation. It was hypothesized that this system will result in enhanced transfection efficiency compared to DNA-Lipoplexes adsorbed to the mineral surface and DNA coprecipitated without Lipofectamine 2000. PLGA films were cast onto glass slips and apatite and DNA were coprecipitated in modified simulated body fluid (mSBF). DNA-Lipoplex presence in mineral, DNA-Lipoplex stability (vs. coprecipitation time), and transfection efficiency (determined with C3H10T1/2 cells) as a function of coprecipitation time, DNA-Lipoplex concentration, and DNA incorporation method were studied. DNA-Lipoplex presence and spatial distribution on apatite were confirmed through fluorescence. Transfection efficiency was highest for 6h of DNA-Lipoplex coprecipitation. Differences in transfection efficiency were found between the DNA concentrations, with the highest efficiency for coprecipitation being 40 microg/ml (p < or = 0.009 relative to other coprecipitation concentrations). Significant differences in transfection efficiency existed between incorporation methods (p < 0.05) with the highest efficiency for DNA-Lipoplex coprecipitation. This hybrid material system not only integrates inductivity provided by the DNA and conductivity provided by the apatite, but it also has significant implications in non-viral gene delivery due to its ability to increase transfection efficiency.