Effect of Pendant Group on pDNA Delivery by Cationic-β-Cyclodextrin:Alkyl-PVA-PEG Pendant Polymer Complexes

摘要

We have previously shown that cationic-β-CD:R-poly(vinyl alcohol)-poly(ethylene glycol) pendant polymer host:guest complexes are safe and efficient vehicles for nucleic acid delivery, where R = benzylidene-linked adamantyl or cholesteryl esters. Herein, we report the synthesis and biological performance of a family of PVA-PEG pendant polymers whose pendant groups have a wide range of different affinities for the β-CD cavity. Cytotoxicity studies revealed that all of the cationic-β-CD:pendant polymer host:guest complexes have 100 – 1000-fold lower toxicity than bPEI, with pDNA transfection efficiencies that are comparable to branched polyethylenimine (bPEI) and Lipofectamine 2000 (L2K). Complexes formed with pDNA at N/P ratios greater than 5 produced particles with diameters in the 100 – 170 nm range and ζ-potentials of 15 – 35 mV. Gel shift and heparin challenge experiments showed that the complexes are most stable at N/P ≥ 10, with adamantyl- and noradamantyl-modified complexes displaying the best resistance toward heparin-induced decomplexation. Disassembly rates of fluoresceinated-pDNA:CD⁺:R-PVA-PEG-rhodamine complexes within HeLa cells showed a modest dependence on host:guest binding constant, with adamantyl-, noradamantyl-, and dodecyl-based complexes showing the highest FRET efficiency 9 h after cellular exposure. These findings suggest that the host:guest binding constant has a significant impact on the colloidal stability in the presence of serum, cellular uptake efficiency, endosomal disassembly, and transfection performance of cationic-β-CD:R-poly(vinyl alcohol)-poly(ethylene glycol) pendant polymer complexes.