| 1. |
- Filippov, Sergey K., et al.
(författare)
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pH sensitive polymer nanoparticles : effect of hydrophobicity on self-assembly
- 2010
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 26:18, s. 14450-14457
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Tidskriftsartikel (refereegranskat)abstract
- The influence of hydrophobicity on formation, stability, and size of pH-responsive methacryloylated oligopeptide-based polymer nanoparticles has been studied by dynamic light scattering (DLS), transmission electron microscopy (Cryo-TEM), and NMR. Different polyanions/surfactant systems have been studied at constant polymer concentration and within a broad range of surfactant concentrations. The two newly synthesized pH-sensitive hydrophobic polyanions, poly(N(ω)-methacryloyl glycyl-L-leucine) and poly(N(ω)-methacryloyl glycyl-L-phenylalanyl-L-leucinyl-glycine), and three nonionic surfactants (Brij97, Brij98, and Brij700) have been investigated. The surfactants were different in the length of hydrophilic poly(ethylene oxide) (PEO) chain. In surfactant-free solution at basic pH, the polyanions form hydrophobic domains. In the presence of a surfactant, our results prove the complex formation at high pH between the nonionic surfactant and the polyelectrolyte; a pearl-necklace structure is formed. At low pH below critical pH (pH(tr)), reversible nanoscale structures occur in solutions for all systems. The detailed mechanism of the formation of pH-sensitive nanoparticles from polymer-surfactant complex with varying pH is established. Our results suggest that the polymer hydrophobicity is of primary importance in pretransitional behavior of the complex. Once preliminary nanoparticle nuclei are formed, the hydrophobicity of the polymer plays a minor role on further behavior of formed nanostructures. The subsequent transformation of nanoparticles is determined by the surfactant hydrophilicity, the length of hydrophilic tail that prevents further aggregation due to steric repulsions.
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| 2. |
- Hruby, Martin, et al.
(författare)
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Thermoresponsive, Hydrolytically Degradable Polymer Micelles Intended for Radionuclide Delivery
- 2009
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Ingår i: Macromolecular Bioscience. - : Wiley. - 1616-5187 .- 1616-5195. ; 9:10, s. 1016-1027
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Tidskriftsartikel (refereegranskat)abstract
- Novel polymer micelles, prepared by self-assembling thermoresponsive poly(N-isopropylacrylamide)-graft-poly[N-(2-hydroxypropyl)methacrylamide] copolymers with hydrolytically degradable N-glycosylamine groups between the polymer blocks are proposed for delivery of diagnostic and therapeutic radionuclides into solid tumors. The micelles are formed by fast heating of an aqueous solution of the copolymer to 37 °C. They have a hydrodynamic diameter of 128 nm (measured using dynamic light scattering) and slowly degrade during incubation in aqueous buffer at pH = 7.4. Labeling with both 131I and 90Y proceeds with high yields (>85%). The unlabeled polymers are not cytotoxic for any of the tested murine and human cell lines.
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| 3. |
- Mahun, Andrii, et al.
(författare)
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Reconstructing Reliable Powder Patterns from Spikelets (Q)CPMG NMR Spectra : Simplification of UWNMR Crystallography Analysis
- 2021
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 26:19
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Tidskriftsartikel (refereegranskat)abstract
- Spikelets NMR spectra are very popular as they enable the shortening of experimental time and give the possibility to obtain required NMR parameters for nuclei with ultrawide NMR patterns. Unfortunately, these resulted ssNMR spectra cannot be fitted directly in common software. For this reason, we developed UWNMRSpectralShape (USS) software which transforms spikelets NMR patterns into single continuous lines. Subsequently, these reconstructed spectral envelopes of the (Q)CPMG spikelets patterns can be loaded into common NMR software and automatically fitted, independently of experimental settings. This allows the quadrupole and chemical shift parameters to be accurately determined. Moreover, it makes fitting of spikelets NMR spectra exact, fast and straightforward.
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| 4. |
- Skodova, Michaela, et al.
(författare)
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Novel Polymeric Nanoparticles Assembled by Metal Ion Addition
- 2011
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Ingår i: Macromolecular Chemistry and Physics. - : Wiley. - 1022-1352 .- 1521-3935. ; 212:21, s. 2339-2348
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Tidskriftsartikel (refereegranskat)abstract
- Potentially biodegradable graft polymer core-shell nanoparticles assembling by addition of metal ions intended to be used for radionuclide and drug delivery purposes are described. With Cu2+ ions, the self-assembly is slow (within minutes) with low efficiency. With Fe3+ ions the nanoparticles are formed immediately and are of convenient size for passive tumor accumulation by the enhanced permeation and retention effect. Full in vitro degradation of these particles is achieved with deferoxamine as a model of in vivo transchelation capacity.
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