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Investigating the effects of block versus statistical glycopolycations containing primary and tertiary amines for plasmid DNA delivery.

Sprouse D, Reineke TM - Biomacromolecules (2014)

Bottom Line: Polyplexes formed with the block copolymers were found to be more colloidally stable than statistical copolymers with similar composition, which rapidly aggregated to micrometer sized particles.Moreover, it was found that increasing the content of tertiary amines imparted higher membrane disruption/destabilization.Overall, the triblock terpolymers offer an attractive composition profile that exhibited interesting properties as pDNA delivery vehicles.

View Article: PubMed Central - PubMed

Affiliation: University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.

ABSTRACT
Polymer composition and morphology can affect the way polymers interact with biomolecules, cell membranes, and intracellular components. Herein, diblock, triblock, and statistical polymers that varied in charge center type (primary and/or tertiary amines) were synthesized to elucidate the role of polymer composition on plasmid DNA complexation, delivery, and cellular toxicity of the resultant polyplexes. The polymers were synthesized via RAFT polymerization and were composed of a carbohydrate moiety, 2-deoxy-2-methacrylamido glucopyranose (MAG), a primary amine group, N-(2-aminoethyl) methacrylamide (AEMA), and/or a tertiary amine moiety, N,N-(2-dimethylamino)ethyl methacrylamide (DMAEMA). The lengths of both the carbohydrate and cationic blocks were kept constant while the primary amine to tertiary amine ratio was varied within the polymers. The polymers were characterized via nuclear magnetic resonance (NMR) and size exclusion chromatography (SEC), and the polyplex formulations with pDNA were characterized in various media using dynamic light scattering (DLS). Polyplexes formed with the block copolymers were found to be more colloidally stable than statistical copolymers with similar composition, which rapidly aggregated to micrometer sized particles. Also, polymers composed of a higher primary amine content were more colloidally stable than polymers consisting of the tertiary amine charge centers. Plasmid DNA internalization, transgene expression, and toxicity were examined with each polymer. As the amount of tertiary amine in the triblock copolymers increased, both gene expression and toxicity were found to increase. Moreover, it was found that increasing the content of tertiary amines imparted higher membrane disruption/destabilization. While both block and statistical copolymers had high transfection efficiencies, some of the statistical systems exhibited both higher transfection and toxicity than the analogous block polymers, potentially due to the lack of a hydrophilic block to screen membrane interaction/disruption. Overall, the triblock terpolymers offer an attractive composition profile that exhibited interesting properties as pDNA delivery vehicles.

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Related in: MedlinePlus

Synthesized copolymer structure. Monomers are MAGX (blue),AEMAY (purple), and DMAEMAZ (red); and the polymeris poly(GX-PY-TZ). N is the total number of repeat units in thepolymer.
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fig1: Synthesized copolymer structure. Monomers are MAGX (blue),AEMAY (purple), and DMAEMAZ (red); and the polymeris poly(GX-PY-TZ). N is the total number of repeat units in thepolymer.

Mentions: To further understandthe role of polymer composition in polyplexformation, delivery efficiency, and cellular cytotoxicity, a seriesof carbohydrate-containing polycations with varying ratios of primaryand/or tertiary amines were synthesized via radical addition–fragmentationchain transfer (RAFT) polymerization. Diblock, triblock, and statisticalco- and terpolymers were created that contain a carbohydrate moiety(MAG), a primary amine (AEMA), and/or a tertiary amine (DMAEMA). Boththe carbohydrate and cationic block lengths were kept constant, whilethe content ratio of primary to tertiary amines was varied withinthe polymer models (Figure 1). The goal ofthis study was to understand and compare the role of (i) charge centercomposition (primary versus tertiary amines) and (ii) polymer structure(statistical versus block) on polyplex formation, pDNA delivery, and,in particular, cell membrane interaction and toxicity. Herein, weshow that these factors play a large role in determining the efficiencyof these delivery vehicles. Polycations containing primary amines(AEMA) promote tight pDNA binding and form colloidally stable polyplexes.While these structures have a lower buffering effect in the cellularpH range, they still promote high delivery and cell viability. Polyplexesformulated with polymers containing tertiary amine (DMAEMA) chargeswere found to have higher cellular internalization profiles but weresignificantly more toxic to cells (due to membrane destabilization).In addition, block versus statistical motifs were examined, and itwas found that as the amount of DMAEMA in the charge block increased,colloidal stability of the polyplexes and cell viability both significantlydecreased.


Investigating the effects of block versus statistical glycopolycations containing primary and tertiary amines for plasmid DNA delivery.

Sprouse D, Reineke TM - Biomacromolecules (2014)

Synthesized copolymer structure. Monomers are MAGX (blue),AEMAY (purple), and DMAEMAZ (red); and the polymeris poly(GX-PY-TZ). N is the total number of repeat units in thepolymer.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215899&req=5

fig1: Synthesized copolymer structure. Monomers are MAGX (blue),AEMAY (purple), and DMAEMAZ (red); and the polymeris poly(GX-PY-TZ). N is the total number of repeat units in thepolymer.
Mentions: To further understandthe role of polymer composition in polyplexformation, delivery efficiency, and cellular cytotoxicity, a seriesof carbohydrate-containing polycations with varying ratios of primaryand/or tertiary amines were synthesized via radical addition–fragmentationchain transfer (RAFT) polymerization. Diblock, triblock, and statisticalco- and terpolymers were created that contain a carbohydrate moiety(MAG), a primary amine (AEMA), and/or a tertiary amine (DMAEMA). Boththe carbohydrate and cationic block lengths were kept constant, whilethe content ratio of primary to tertiary amines was varied withinthe polymer models (Figure 1). The goal ofthis study was to understand and compare the role of (i) charge centercomposition (primary versus tertiary amines) and (ii) polymer structure(statistical versus block) on polyplex formation, pDNA delivery, and,in particular, cell membrane interaction and toxicity. Herein, weshow that these factors play a large role in determining the efficiencyof these delivery vehicles. Polycations containing primary amines(AEMA) promote tight pDNA binding and form colloidally stable polyplexes.While these structures have a lower buffering effect in the cellularpH range, they still promote high delivery and cell viability. Polyplexesformulated with polymers containing tertiary amine (DMAEMA) chargeswere found to have higher cellular internalization profiles but weresignificantly more toxic to cells (due to membrane destabilization).In addition, block versus statistical motifs were examined, and itwas found that as the amount of DMAEMA in the charge block increased,colloidal stability of the polyplexes and cell viability both significantlydecreased.

Bottom Line: Polyplexes formed with the block copolymers were found to be more colloidally stable than statistical copolymers with similar composition, which rapidly aggregated to micrometer sized particles.Moreover, it was found that increasing the content of tertiary amines imparted higher membrane disruption/destabilization.Overall, the triblock terpolymers offer an attractive composition profile that exhibited interesting properties as pDNA delivery vehicles.

View Article: PubMed Central - PubMed

Affiliation: University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.

ABSTRACT
Polymer composition and morphology can affect the way polymers interact with biomolecules, cell membranes, and intracellular components. Herein, diblock, triblock, and statistical polymers that varied in charge center type (primary and/or tertiary amines) were synthesized to elucidate the role of polymer composition on plasmid DNA complexation, delivery, and cellular toxicity of the resultant polyplexes. The polymers were synthesized via RAFT polymerization and were composed of a carbohydrate moiety, 2-deoxy-2-methacrylamido glucopyranose (MAG), a primary amine group, N-(2-aminoethyl) methacrylamide (AEMA), and/or a tertiary amine moiety, N,N-(2-dimethylamino)ethyl methacrylamide (DMAEMA). The lengths of both the carbohydrate and cationic blocks were kept constant while the primary amine to tertiary amine ratio was varied within the polymers. The polymers were characterized via nuclear magnetic resonance (NMR) and size exclusion chromatography (SEC), and the polyplex formulations with pDNA were characterized in various media using dynamic light scattering (DLS). Polyplexes formed with the block copolymers were found to be more colloidally stable than statistical copolymers with similar composition, which rapidly aggregated to micrometer sized particles. Also, polymers composed of a higher primary amine content were more colloidally stable than polymers consisting of the tertiary amine charge centers. Plasmid DNA internalization, transgene expression, and toxicity were examined with each polymer. As the amount of tertiary amine in the triblock copolymers increased, both gene expression and toxicity were found to increase. Moreover, it was found that increasing the content of tertiary amines imparted higher membrane disruption/destabilization. While both block and statistical copolymers had high transfection efficiencies, some of the statistical systems exhibited both higher transfection and toxicity than the analogous block polymers, potentially due to the lack of a hydrophilic block to screen membrane interaction/disruption. Overall, the triblock terpolymers offer an attractive composition profile that exhibited interesting properties as pDNA delivery vehicles.

Show MeSH
Related in: MedlinePlus