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Characterization of complexation of poly (N-isopropylacrylamide-co-2-(dimethylamino) ethyl methacrylate) thermoresponsive cationic nanogels with salmon sperm DNA.

Moselhy J, Vira T, Liu FF, Wu XY - Int J Nanomedicine (2009)

Bottom Line: Quaternized P[NIPAM/DMAEMAQ] TCNGs did not undergo sharp VPT up to 50 degrees C.The VPT of P[NIPAM/DMAEMAQ]/sasDNA diminished in magnitude with increasing W(p)/W(d) suggesting greater compaction of the polyplexes.The findings demonstrate that stable TCNGs can be prepared with controllable responsive properties determined by the nature of the cationic charge incorporated and may have potential as vehicles for DNA delivery.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada M5S 3M2.

ABSTRACT
Thermoresponsive cationic nanogel (TCNG) networks based on N-isopropylacrylamide (NIPAM), 2-(dimethylamino)ethyl methacrylate (DMAEMA), and quaternary alkyl ammonium halide salts of DMAEMA (DMAEMAQ) were synthesized by dispersion polymerization technique. The thermoresponsive properties of TCNGs and TCNG-salmon sperm DNA (sasDNA) polyplexes were characterized in aqueous media of various pH and ionic strength. P[NIPAM] and P[NIPAM/DMAEMA] TCNGs exhibited sharp volume phase transition (VPT) in water at critical temperatures (T(c)) of 32 degrees C and 36 degrees C, respectively. Quaternized P[NIPAM/DMAEMAQ] TCNGs did not undergo sharp VPT up to 50 degrees C. The VPT of uncomplexed TCNGs were sensitive to the ionic composition and ionic strength of salts in solution, but were insensitive to pH in the range 5.0 to 7.4. The VPT of P[NIPAM/DMAEMAQ]/sasDNA diminished in magnitude with increasing W(p)/W(d) suggesting greater compaction of the polyplexes. The distinct phase-transition properties of P[NIPAM/DMAEMA]/sasDNA and P[NIPAM/DMAEMAQ]/sasDNA polyplexes were attributed to the condensing capability of polycations and to differences in the spatial distribution of structural charges in quaternized and nonquaternized networks. The findings demonstrate that stable TCNGs can be prepared with controllable responsive properties determined by the nature of the cationic charge incorporated and may have potential as vehicles for DNA delivery.

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Temperature dependence of particle size of cationic P[NIPAM] and P[NIPAM/DMAEM] NGs in DDIW (n = 3). Arrows denote loss of particle stability and aggregation.
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f2-ijn-4-153: Temperature dependence of particle size of cationic P[NIPAM] and P[NIPAM/DMAEM] NGs in DDIW (n = 3). Arrows denote loss of particle stability and aggregation.

Mentions: Figure 2 compares the thermal response profiles of the N100 P[NIPAM] TCNG with DMAEMA functionalized TCNGs in DDIW. The N100 TCNG, whose charge originates from AIBH initiator residues and surfactant DTAB, retained its stability through the entire temperature range up to 50 °C. This is in contrast to the TCNGs functionalized with 9%mol DMAEMA, ND9-1 and ND9-2, which lost stability above the LCST.


Characterization of complexation of poly (N-isopropylacrylamide-co-2-(dimethylamino) ethyl methacrylate) thermoresponsive cationic nanogels with salmon sperm DNA.

Moselhy J, Vira T, Liu FF, Wu XY - Int J Nanomedicine (2009)

Temperature dependence of particle size of cationic P[NIPAM] and P[NIPAM/DMAEM] NGs in DDIW (n = 3). Arrows denote loss of particle stability and aggregation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2747350&req=5

f2-ijn-4-153: Temperature dependence of particle size of cationic P[NIPAM] and P[NIPAM/DMAEM] NGs in DDIW (n = 3). Arrows denote loss of particle stability and aggregation.
Mentions: Figure 2 compares the thermal response profiles of the N100 P[NIPAM] TCNG with DMAEMA functionalized TCNGs in DDIW. The N100 TCNG, whose charge originates from AIBH initiator residues and surfactant DTAB, retained its stability through the entire temperature range up to 50 °C. This is in contrast to the TCNGs functionalized with 9%mol DMAEMA, ND9-1 and ND9-2, which lost stability above the LCST.

Bottom Line: Quaternized P[NIPAM/DMAEMAQ] TCNGs did not undergo sharp VPT up to 50 degrees C.The VPT of P[NIPAM/DMAEMAQ]/sasDNA diminished in magnitude with increasing W(p)/W(d) suggesting greater compaction of the polyplexes.The findings demonstrate that stable TCNGs can be prepared with controllable responsive properties determined by the nature of the cationic charge incorporated and may have potential as vehicles for DNA delivery.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada M5S 3M2.

ABSTRACT
Thermoresponsive cationic nanogel (TCNG) networks based on N-isopropylacrylamide (NIPAM), 2-(dimethylamino)ethyl methacrylate (DMAEMA), and quaternary alkyl ammonium halide salts of DMAEMA (DMAEMAQ) were synthesized by dispersion polymerization technique. The thermoresponsive properties of TCNGs and TCNG-salmon sperm DNA (sasDNA) polyplexes were characterized in aqueous media of various pH and ionic strength. P[NIPAM] and P[NIPAM/DMAEMA] TCNGs exhibited sharp volume phase transition (VPT) in water at critical temperatures (T(c)) of 32 degrees C and 36 degrees C, respectively. Quaternized P[NIPAM/DMAEMAQ] TCNGs did not undergo sharp VPT up to 50 degrees C. The VPT of uncomplexed TCNGs were sensitive to the ionic composition and ionic strength of salts in solution, but were insensitive to pH in the range 5.0 to 7.4. The VPT of P[NIPAM/DMAEMAQ]/sasDNA diminished in magnitude with increasing W(p)/W(d) suggesting greater compaction of the polyplexes. The distinct phase-transition properties of P[NIPAM/DMAEMA]/sasDNA and P[NIPAM/DMAEMAQ]/sasDNA polyplexes were attributed to the condensing capability of polycations and to differences in the spatial distribution of structural charges in quaternized and nonquaternized networks. The findings demonstrate that stable TCNGs can be prepared with controllable responsive properties determined by the nature of the cationic charge incorporated and may have potential as vehicles for DNA delivery.

Show MeSH
Related in: MedlinePlus