Quantitation of complexed versus free polymers in interpolyelectrolyte polyplex formulations

Xiaoling Wang; Sneha S. Kelkar; Amanda G. Hudson; Robert B. Moore; Theresa M. Reineke; Louis A. Madsen

doi:10.1021/mz400500q

Quantitation of complexed versus free polymers in interpolyelectrolyte polyplex formulations

Xiaoling Wang, Sneha S. Kelkar, Amanda G. Hudson, Robert B. Moore, Theresa M. Reineke, Louis A. Madsen

Chemistry (Twin Cities)

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15 Scopus citations

Abstract

The quantity of free polymer in a polymer/DNA complex (polyplex) formulation critically impacts its gene transfection efficiency, cellular uptake, and toxicity. In this study, the compositions of three interpolyelectrolyte polyplex formulations were quantified by a facile NMR method. Using careful integration of a 1D ¹H NMR spectrum with a broad spectral width, the quantities of unbound polymer and polyplexes in solution were determined. Linear polyethyleneimine (PEI) mixed with DNA at polymer amine to DNA phosphate molar ratio (N/P ratio) of 5 revealed an effective binding N/P ratio of 3.5 without excess free polymer. This result is in strong agreement with the stoichiometric number of PEI/DNA binding obtained by isothermal titration calorimetry. The noninvasive nature of this method allows broad application to a range of polyelectrolyte coacervates, opening new opportunities for understanding and optimizing polyelectrolyte complex formation and providing quantitation of complex formation in a single measurement.

Original language	English (US)
Pages (from-to)	1038-1041
Number of pages	4
Journal	ACS Macro Letters
Volume	2
Issue number	11
DOIs	https://doi.org/10.1021/mz400500q
State	Published - Nov 19 2013

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title = "Quantitation of complexed versus free polymers in interpolyelectrolyte polyplex formulations",

abstract = "The quantity of free polymer in a polymer/DNA complex (polyplex) formulation critically impacts its gene transfection efficiency, cellular uptake, and toxicity. In this study, the compositions of three interpolyelectrolyte polyplex formulations were quantified by a facile NMR method. Using careful integration of a 1D 1H NMR spectrum with a broad spectral width, the quantities of unbound polymer and polyplexes in solution were determined. Linear polyethyleneimine (PEI) mixed with DNA at polymer amine to DNA phosphate molar ratio (N/P ratio) of 5 revealed an effective binding N/P ratio of 3.5 without excess free polymer. This result is in strong agreement with the stoichiometric number of PEI/DNA binding obtained by isothermal titration calorimetry. The noninvasive nature of this method allows broad application to a range of polyelectrolyte coacervates, opening new opportunities for understanding and optimizing polyelectrolyte complex formation and providing quantitation of complex formation in a single measurement.",

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T1 - Quantitation of complexed versus free polymers in interpolyelectrolyte polyplex formulations

AU - Wang, Xiaoling

AU - Kelkar, Sneha S.

AU - Hudson, Amanda G.

AU - Moore, Robert B.

AU - Reineke, Theresa M.

AU - Madsen, Louis A.

PY - 2013/11/19

Y1 - 2013/11/19

N2 - The quantity of free polymer in a polymer/DNA complex (polyplex) formulation critically impacts its gene transfection efficiency, cellular uptake, and toxicity. In this study, the compositions of three interpolyelectrolyte polyplex formulations were quantified by a facile NMR method. Using careful integration of a 1D 1H NMR spectrum with a broad spectral width, the quantities of unbound polymer and polyplexes in solution were determined. Linear polyethyleneimine (PEI) mixed with DNA at polymer amine to DNA phosphate molar ratio (N/P ratio) of 5 revealed an effective binding N/P ratio of 3.5 without excess free polymer. This result is in strong agreement with the stoichiometric number of PEI/DNA binding obtained by isothermal titration calorimetry. The noninvasive nature of this method allows broad application to a range of polyelectrolyte coacervates, opening new opportunities for understanding and optimizing polyelectrolyte complex formation and providing quantitation of complex formation in a single measurement.

AB - The quantity of free polymer in a polymer/DNA complex (polyplex) formulation critically impacts its gene transfection efficiency, cellular uptake, and toxicity. In this study, the compositions of three interpolyelectrolyte polyplex formulations were quantified by a facile NMR method. Using careful integration of a 1D 1H NMR spectrum with a broad spectral width, the quantities of unbound polymer and polyplexes in solution were determined. Linear polyethyleneimine (PEI) mixed with DNA at polymer amine to DNA phosphate molar ratio (N/P ratio) of 5 revealed an effective binding N/P ratio of 3.5 without excess free polymer. This result is in strong agreement with the stoichiometric number of PEI/DNA binding obtained by isothermal titration calorimetry. The noninvasive nature of this method allows broad application to a range of polyelectrolyte coacervates, opening new opportunities for understanding and optimizing polyelectrolyte complex formation and providing quantitation of complex formation in a single measurement.

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ER -

Quantitation of complexed versus free polymers in interpolyelectrolyte polyplex formulations

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