Phase Behavior of Reverse Poloxamers and Poloxamines in Water

Larrañeta, Eneko; Isasi, José Ramón

doi:10.1021/la304245p

Cited by 52 publications

(53 citation statements)

References 29 publications

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“…By controlling their concentration and temperature, Pluronics self-assemble into micelles and gels in aqueous media. [27][28][29][30][31] The interaction between native CDs and Pluronics leading to the formation of PRs and PPRs has been described in the literature. 32,33 The substitution of the hydroxyl groups on the rims of the CD strongly modifies the aggregation behavior of the Pluronic micelles, depending on the specific nature of the substituents, [34][35][36] and the kinetics and mechanisms of the formation of the PPRs have been studied.…”

Section: Introductionmentioning

confidence: 99%

Pseudo-Polyrotaxanes of Cyclodextrins with Direct and Reverse X-Shaped Block Copolymers: A Kinetic and Structural Study

et al. 2019

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Pseudo-polyrotaxanes (PPRs) are supramolecular host-guest complexes constituted by the reversible threading of a macrocycle along a polymer chain, which offers potential applications in nanotechnology, drug delivery and biomaterials. We report the threading of cyclodextrins (CDs), cyclic oligosaccharides, onto X-shaped PEO-PPO block-copolymers, with two opposite presentation of their hydrophobic and hydrophilic blocks: Tetronic 904 (T904), and its reverse counterpart, Tetronic T90R4. We assess the effect of relative block position on the polymeric surfactants and cavity size of CD have on the composition, morphology, thermodynamics and kinetics of PPRs by using a combination of X-ray diffraction, Scanning Electron Microscopy (SEM), NMR, UV-Vis spectroscopy and Time-Resolved Small-Angle Neutron Scattering (TR-SANS). Solid PPRs with lamellar microstructure and crystalline channel-like structures are obtained with native CDs and both Tetronics above a threshold concentration of the macrocycle, which varies with the type of CD and surfactant. While γ-CD can form PPRs with both Tetronics, α-CD only form a PPR with T90R4 at high concentrations. The results can be explained in terms of the preferential complexation of α-CD with EO and γ-CD with PO monomers, which also has a direct impact on the kinetics of PPR formation. Thermodynamic parameters of the reaction were obtained from the analysis of the stoichiometries and threading times as a function of temperature by using a model based on the Eyring equation. Negative enthalpies and positive entropies are obtained in all cases, and reactions are thermodynamically most favorable in the case of α-CD with T904 and γ-CD with T90R4. TR-SANS experiments reveal an increase in the radius of gyration of the unimers over time, consistent with CDthreading and expansion of the PPR. Above the CMT, α-CD threads the unimers to form the PPR, with no effect on the structure of T904 micelles, whose volume fraction decreases due to the shift of micellization equilibrium.

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Section: Introductionmentioning

confidence: 99%

Pseudo-Polyrotaxanes of Cyclodextrins with Direct and Reverse X-Shaped Block Copolymers: A Kinetic and Structural Study

et al. 2019

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“…The number of PO and EO units that form the arms can be varied, offering a wide range of Mw and HLB values, and hence a rich phase behaviour and custom-made properties, both in terms of thermal and pH response. [2][3][4] PEO-PPO-based polymeric micelles are now emerging as promising formulation candidates in the biomedical field, being available in large quantities in a large array of architectures, at low-cost, and also showing biological inhibitory activity of drug efflux pumps. 5,6 The more well-known linear counterparts of Tetronics -Pluronicare currently undergoing clinical trials with the cancer drug doxorubicin 7 and the recent demonstration of the ability of Tetronics to also inhibit ATP-binding cassette transporters in cancer cell lines, responsible for multidrug resistance, 5 added to their pH-responsiveness, has recently brought them into the spotlight as serious contenders in the biomedical field.…”

Section: Introductionmentioning

confidence: 99%

Structure and Rheology of Poloxamine T1107 and Its Nanocomposite Hydrogels with Cyclodextrin-Modified Barium Titanate Nanoparticles

et al. 2016

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We report the preparation of a nanocomposite hydrogel based on a poloxamine gel matrix (Tetronic T1107) and cyclodextrin (CD)-modified barium titanate (BT) nanoparticles. The micellization and sol-gel behavior of pH-responsive block copolymer T1107 were fully characterized by small-angle neutron scattering (SANS), dynamic light scattering (DLS), and Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy as a function of concentration, pH and temperature. SANS results reveal that spherical micelles in the low concentration regime present a dehydrated core and highly hydrated shell, with a small aggregation number and size, highly dependent on the degree of protonation of the central amine spacer. At high concentration, T1107 undergoes a sol-gel transition, which is inhibited at acidic pH. Nanocomposites were prepared by incorporating CD-modified BT of two different sizes (50 and 200 nm) in concentrated polymer solutions. Rheological measurements show a broadening of the gel region, as well as an improvement of the mechanical properties, as assessed by the shear elastic modulus, G' (up to 200% increase). Initial cytocompatibility studies of the nanocomposites show that the materials are nontoxic with viabilities over 70% for NIH3T3 fibroblast cell lines. Overall, the combination of Tetronics and modified BaTiO3 provides easily customizable systems with promising applications as soft piezoelectric materials.

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“…We recently described the synthesis and properties of water‐soluble triblock copolymers containing a central PEG block and terminal poly(trimethylene carbonate/dithiolane) (PTMCDT) blocks (Figure ) . Some of these triblock copolymers spontaneously self‐assemble in water to form flower micelles at low concentrations . We selected the triblock copolymer 1 synthesized from PEG diols of M n =14 KDa with ten units of TMCDT (five in each terminal block; PEG14K/DP10) as a model polymer for this study.…”

Section: Figurementioning

confidence: 99%

Formation of Polymeric Nanocubes by Self‐Assembly and Crystallization of Dithiolane‐Containing Triblock Copolymers

et al. 2017

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Template-free fabrication of non-spherical polymeric nanoparticles is desirable for various applications,b ut has had limited success owing to thermodynamic favorability of sphere formation. Herein we present as imple way to prepare cubic nanoparticles of blockcopolymers by self-assembly from aqueous solutions at room temperature.Nanocubes with edges of 40-200 nm are formed spontaneously on different surfaces upon water evaporation from micellar solutions of triblock copolymers containing ac entral poly(ethylene oxide) block and terminal trimethylene carbonate/dithiolane blocks.T hese polymers self-assemble into 28 AE 5nmmicelles in water.Upon drying, micelle aggregation and ak inetically controlled crystallization of central blocks evidently induce solid cubic particle formation. An approach for preserving the structures of these cubes in water by thiol-or photo-induced crosslinking was developed. The ability to solubilizeamodel hydrophobic drug, curcumin, was also explored.

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Phase Behavior of Reverse Poloxamers and Poloxamines in Water

Cited by 52 publications

References 29 publications

Pseudo-Polyrotaxanes of Cyclodextrins with Direct and Reverse X-Shaped Block Copolymers: A Kinetic and Structural Study

Pseudo-Polyrotaxanes of Cyclodextrins with Direct and Reverse X-Shaped Block Copolymers: A Kinetic and Structural Study

Structure and Rheology of Poloxamine T1107 and Its Nanocomposite Hydrogels with Cyclodextrin-Modified Barium Titanate Nanoparticles

Formation of Polymeric Nanocubes by Self‐Assembly and Crystallization of Dithiolane‐Containing Triblock Copolymers

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