Chemical Physics Letters, Vol.456, No.4-6, 189-192, 2008
Interaction and morphology of polyethylenimine/DNA complexes as studied by solid-state NMR spectroscopy
Solid-state H-1 wide-line and P-31 magic angle spinning NMR were applied to a series of PEI( polyethylenimine)/DNA complexes. The experimental results revealed that the higher the nitrogen/phosphorus (N/P) molar ratio is, the more phosphorus atoms of DNA are engaged in the electrostatic interaction with PEI. H-1 spin-diffusion experiments manifested that the aggregation degree of DNA in the complexes decreases greatly when N/P ratio increases from 0.5 to 3 and changes only slightly with further increase of N/P ratio, indicating that DNA disperses in the matrix of PEI on the molecular level at higher N/P ratio. (c) 2008 Elsevier B. V. All rights reserved.