Star Polymer/Water Solutions: New Experimental Findings

Branca,; Magazu,; Migliardo,

doi:10.5488/cmp.5.2.275

Cited by 5 publications

(5 citation statements)

References 10 publications

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“…Our data also demonstrated that nature of the polymer backbone is sufficiently amphiphilic for self‐assembly, and that there is an equilibrium between molecular unimers and aggregates in solution. Our results are consistent with earlier studies showing that there is an equilibrium between unimers and aggregates in a solution containing 4‐arm star block copolymer, sP(EO‐block‐PO) . In addition, our results are supported by studies showing that both linear block copolymers and linear gradient copolymers of EO and PO undergo self‐assembly …”

Section: Resultssupporting

confidence: 92%

“…Our results are consistent with earlier studies showing that there is an equilibrium between unimers and aggregates in a solution containing 4-arm star block copolymer, sP(EO-block-PO). [38] In addition, our results are supported by Reactive polymers are then prepared by endcapping the hydroxy terminated polymer HO-sP(EO-stat-PO) with IPDI. Hydrolysis of the isocyanate groups first leads to the formation of carbamic acid and amino groups.…”

Section: Self-assembly Of Nanogelssupporting

confidence: 58%

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Reactive Self‐Assembly and Specific Cellular Delivery of NCO‐sP(EO‐stat‐PO)‐Derived Nanogels

Hildebrandt

Paloheimo

Mäntylä

et al. 2018

Macromolecular Bioscience

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This study presents the reactive self-assembly of isocyanate functional and amphiphilic six-arm, star-shaped polyether prepolymers in water into nanogels. Intrinsic molecular amphiphilicity, mainly driven by the isophorone moiety at the distal endings of the star-shaped molecules, allows for the preparation of spherical particles with an adjustable size of 100-200 nm by self-assembly and subsequent covalent cross-linking without the need for organic solvents or surfactants. Covalent attachment of a fluorescence dye and either the cell-penetrating TAT peptide or a random control peptide sequence shows that only TAT-labeled nanogels are internalized by HeLa cells. The nanogels thus specifically enter the cells and accumulate in the perinuclear area in a time- and concentration-dependent manner.

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Section: Resultssupporting

confidence: 92%

Section: Self-assembly Of Nanogelssupporting

confidence: 58%

Reactive Self‐Assembly and Specific Cellular Delivery of NCO‐sP(EO‐stat‐PO)‐Derived Nanogels

Hildebrandt

Paloheimo

Mäntylä

et al. 2018

Macromolecular Bioscience

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“…Strongly temperature dependent micellization and gelation of these amphiphilic copolymers have been thoroughly examined in the last few decades though mostly on linear PEO–PPO–PEO triblock copolymers and there exist several reviews [ 1 , 15 , 16 ]. However, only a few authors have reported on the aqueous solution behavior of their star shaped counterparts [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study on Micellar and Solubilizing Behavior of Three EO-PO Based Star Block Copolymers Varying in Hydrophobicity and Their Application for the In Vitro Release of Anticancer Drugs

et al. 2018

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Abstract:The temperature and pH dependent self-assembly of three star shaped ethylene oxide-propylene oxide (EO-PO) block copolymers (Tetronics ® 304, 904 and 908) with widely different hydrophobicity was examined in aqueous solutions. Physico-chemical methods viz. viscosity, cloud point, solubilization along with thermal, scattering and spectral techniques shows strongly temperature and salt dependent solution behavior. T304 possessing low molecular weight did not form micelles; moderately hydrophilic T904 remained as micelles at ambient temperature and showed micellar growth while very hydrophilic T908 formed micelles at elevated temperatures. The surface activity/micellization/solubilization power was favored in the presence of salt. The copolymers turn more hydrophilic in acidic pH due to protonation of central ethylene diamine moiety that hinders micelle formation. The solubilization of a model insoluble azo dye 1-(o-Tolylazo)-2-naphthol (Orange OT) and hydrophobic drugs (quercetin and curcumin) for copolymer solutions in aqueous and salt solutions are also reported. Among the three copolymers, T904 showed maximum solubility of dye and drugs, hence the in vitro release of drugs from T904 micelles was estimated and the effect on cytotoxicity of loading the drugs in T904 micelles was compared with the cytotoxicity of free drugs on the CHO-K1 cells. The results from the present work provide a better insight in selection of Tetronics ® for their application in different therapeutic applications.

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“…While previous SANS studies on this Tetronic have been reported in the literature, they were specifically focused on the structure of the gel phase under flow. [29][30][31][32] This is the first structural study covering the micelles from the dilute to the concentrated regime including the gel phase, through the combined use dynamic light scattering (DLS), small-angle neutron scattering (SANS), steady-state and time-resolved fluorescence,…”

mentioning

confidence: 99%

Phase behaviour, micellar structure and linear rheology of tetrablock copolymer Tetronic 908

Puig-Rigall

Obregon-Gomez

Monreal-Pérez

et al. 2018

Journal of Colloid and Interface Science

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Tetronics are X-shaped block-copolymers of polyethylene oxide and polypropylene oxide, which self-assemble into micelles and can undergo a sol-gel transition; these transitions are dependent on temperature, concentration but also pH, due to the central diamine group of the tetrablock. We report the nanoscale morphologies underlying these different phases and the rheology of the systems for a very large, highly hydrophilic block copolymer, Tetronic 908, through the combined use of oscillatory rheology, steadyblock-state and time-resolved fluorescence, small-angle neutron scattering (SANS), dynamic light scattering (DLS) and Fourier transform infrared attenuated total reflectance (FTIR-ATR). At low concentrations, SANS reveal core-shell micelles of ca. 10 nm radius, presenting a dehydrated core and a highly hydrated shell, with relatively small aggregation numbers (N ≈ 13). The micelles are notably affected by the pH, due to the protonation of the central amine spacer at low pH (pH ≈ 2), which shifts micellization to higher temperature, with smaller micelles than at natural pH. In the intermediate concentration regime (10-15%), micelles become smaller (N ≈ 5), and present a higher hydration of the core. In the high concentration regime, Tetronic 908 undergoes a sol-gel transition above a threshold temperature, which is fully inhibited at acidic pH. SANS data from the gel phase reveal a BCC order of tightly packed spheres. Temperature sweeps in oscillatory rheology show a shift of the onset of gelation towards lower temperatures as concentration increases, an increase in the elastic modulus G' and an expansion of gel region over a larger range of temperatures. SANS and rheology reveal that at pH below the natural pH (ca. 8), gelation is shifted to higher temperatures, but the morphology of the gels is similar, while under highly acidic conditions the gelation is fully suppresed.

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Star Polymer/Water Solutions: New Experimental Findings

Cited by 5 publications

References 10 publications

Reactive Self‐Assembly and Specific Cellular Delivery of NCO‐sP(EO‐stat‐PO)‐Derived Nanogels

Reactive Self‐Assembly and Specific Cellular Delivery of NCO‐sP(EO‐stat‐PO)‐Derived Nanogels

A Comparative Study on Micellar and Solubilizing Behavior of Three EO-PO Based Star Block Copolymers Varying in Hydrophobicity and Their Application for the In Vitro Release of Anticancer Drugs

Phase behaviour, micellar structure and linear rheology of tetrablock copolymer Tetronic 908

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