Folate Receptor‐Mediated Gene Delivery Using Folate‐Poly(ethylene glycol)‐Poly(L‐lysine) Conjugate

Abstract Summary: For efficient receptor‐mediated gene transfection, a new and simple formulation method based on using PEI and FOLPEGPLL conjugate was presented. Luciferase plasmid DNA and PEI were complexed to form slightly positive‐charged nanoparticles, onto which FOL‐PEG‐PLL conjugate was surface coated. With increasing the coating amount of FOL‐PEG‐PLL conjugate, the FOL‐PEG‐PLL/PEI/DNA complexes exhibited increased surface zeta‐potential values with concomitantly increased diameters, indicating that the PLL part was physically anchored on the surface of preformed PEI/DNA complexes with FOL moieties being exposed on the outside. The formulated complexes exhibited a considerably higher transfection efficiency against FOL receptor over‐expressing KB cells than FOL receptor deficient A549 cells. This was caused by an enhanced cellular uptake of the resultant complexes via a receptor‐mediated endocytosis process. The formulated complexes showed a higher gene expression level, even in the presence of serum, than the PEI/DNA or Lipofectamine/DNA complexes. This was attributed to the PEG chains present on the surface of complexes that could work as a protective shield layer against aggregation caused by non‐specific protein adsorption. The FOL‐PEG‐PLL/PEI/DNA complexes also demonstrated better cell viability than the PEI/DNA complexes. 1 H NMR spectrum of FOL‐PEG‐PLL conjugate. magnified image 1 H NMR spectrum of FOL‐PEG‐PLL conjugate.