LDH-DNA Nanohybrids:a complete biophysical characterization

摘要

Recently,LDH have been considered as a new kind of gene delivery system [1,2].In this work,we report the formation of magnesium-gallium LDH-DNA nanohybrids using the coprecipitation method.This"self assembly"approach enabled the incorporation of long DNA fragments up to 6000-8000 bp.X-ray diffraction analyses indicate a parallel orientation of DNA double helix in the interlamellar space with respect to the hydroxide sheets.The Mg/Ga molar ratio within the hydroxide layers appears to be determined by DNA macromolecules which may interact with charged complexes that form during cation hydrolysis.The presence of DNA macromolecules also inhibits the crystal growth:hydrodynamic diameter measurements revealed homogeneous populations of particles with a mean diameter ranging from 90 to 150 nm,compatible with cell penetration through endocytosis.Concerning the charge surface of this new DNA delivery system,zeta-potential measurements indicate negative values ranging from-20 to-40 mV which suggest incomplete DNA intercalation.Yet,this small negative surface might be suitable for protecting DNA from extra-cellular degradations without preventing cell penetration.