Single-chain folding and self-assembling of amphiphilic polyethyleneglycol-modified fluorinated styrene homopolymers in water solution

Guazzelli, Elisa; Masotti, Elena; Calosi, Matteo; Kriechbaum, Manfred; Uhlig, F.; Galli, Giancarlo; Martinelli, Elisa

doi:10.1016/j.polymer.2021.124107

Cited by 10 publications

(12 citation statements)

References 52 publications

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“…However, the incorporation of the fluorinated co-units in the amphiphilic copolymers led to a lower LCST than that reported for analogous non-fluorinated ones. The inclusion of low surface energy fluoroalkyl side chains in a polymer structure is, in fact, known to drastically enhance the hydrophobic and lipophobic nature of the entire system, which results in a strong tendency to self-assemble in solution, in bulk and at the surface of thin films [15][16][17][18]. Follow-up studies by our group on similar copolymers of PEGMA and perfluorohexylethyl acrylate (FA) identified the formation of self-folded nanostructures by several complementary experimental analyses, including neutron scattering and molecular dynamics simulations, and we also studied the thermoresponsive features of the copolymers, which reversibly collapsed and aggregated into multi-chain aggregates at temperatures varying with copolymer composition [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Self-Assembled Amphiphilic Fluorinated Random Copolymers for the Encapsulation and Release of the Hydrophobic Combretastatin A-4 Drug

et al. 2022

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Water-soluble amphiphilic random copolymers composed of tri(ethylene glycol) methacrylate (TEGMA) or poly(ethylene glycol) methyl ether methacrylate (PEGMA) and perfluorohexylethyl acrylate (FA) were synthesized by ARGET-ATRP, and their self-assembling and thermoresponsive behavior in water was studied by dynamic light scattering (DLS) and UV-vis spectroscopy. The copolymer ability to self-fold in single-chain nano-sized structures (unimer micelles) in aqueous solutions was exploited to encapsulate Combretastatin A-4 (CA-4), which is a very hydrophobic anticancer drug. The cloud point temperature (Tcp) was found to linearly decrease with increasing drug concentration in the drug/copolymer system. Moreover, while CA-4 was preferentially incorporated into the unimer micelles of TEGMA-ran-FA, the drug was found to induce multi-chain, submicro-sized aggregation of PEGMA-ran-FA. Anyway, the encapsulation efficiency was very high (≥81%) for both copolymers. The drug release was evaluated in PBS aqueous solutions both below and above Tcp for TEGMA-ran-FA copolymer and below Tcp, but at two different drug loadings, for PEGMA-ran-FA copolymer. In any case, the release kinetics presented similar profiles, characterized by linear trends up to ≈10–13 h and ≈7 h for TEGMA-ran-FA and PEGMA-ran-FA, respectively. Then, the release rate decreased, reaching a plateau. The release from TEGMA-ran-FA was moderately faster above Tcp than below Tcp, suggesting that copolymer thermoresponsiveness increased the release rate, which occurred anyway by diffusion below Tcp. Cytotoxicity tests were carried out on copolymer solutions in a wide concentration range (5–60 mg/mL) at 37 °C by using Balb/3T3 clone A31 cells. Interestingly, it was found that the concentration-dependent micro-sized aggregation of the amphiphilic random copolymers above Tcp caused a sort of “cellular asphyxiation” with a loss of cell viability clearly visible for TEGMA-ran-FA solutions (Tcp below 37 °C) with higher copolymer concentrations. On the other hand, cells in contact with the analogous PEGMA-ran-FA (Tcp above 37 °C) presented a very good viability (≥75%) with respect to the control at any given concentration.

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Section: Introductionmentioning

confidence: 99%

Self-Assembled Amphiphilic Fluorinated Random Copolymers for the Encapsulation and Release of the Hydrophobic Combretastatin A-4 Drug

et al. 2022

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“…Furthermore, the responsive self‐folding and self‐assembly of copolymers, which is typically driven by the hydrophobic effect in water, is non‐restricted to the use of water as a solvent. [ 32–38 ] As a function of the nature of the environment, the remodeling of SCNPs from a compact globular conformation (in highly polar solvents) to the reverse globule (in highly nonpolar solvents) was predicted through molecular dynamics simulations, [ 39 ] while the same copolymers exhibited unfolded extended conformations in solvents of intermediate polarity. [ 39,40 ]…”

Section: Introductionmentioning

confidence: 99%

Thermoresponsive Reversible Unimer Micelles of Amphiphilic Fluorinated Copolymers

Guazzelli

Masotti

Kriechbaum

et al. 2022

Macro Chemistry & Physics

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Amphiphilic fluorinated copolymers PEGMAx-co-FAy and TEGMAx-co-FAy are prepared by activators regenerated by electron transfer atom transfer radical polymerization (ARGET-ATRP). All polymers present a reversible thermoresponsive lower critical solution temperature-type behavior, and a cloud point temperature (T c ) in the range of 30-60 °C strictly dependent on the length of the oxyethylene side chain, the content of the hydrophobic counits, and the concentration of the solution. Combined small angle X-ray scattering (SAXS) and dynamic light scattering measurements are used to study the self-assembly behavior in water, organic solvents (tetrahydrofuran [THF] and dimethylformamide [DMF]), and a fluorinated solvent (hexafluorobenzene [HFB]). SAXS confirms the formation of compact-globular single-chain self-folded unimer micelles in water below T c , which generally presents small hydrodynamic diameters (D h ≤ 8 nm) as a result of the folding of the hydrophobic perfluorohexylethyl acrylate counits. The copolymers are also able to form reverse unimer micelle in HFB. The copolymers are not able to self-assemble in unimer micelles in THF or DMF solutions, in which they adopt conventional random coil conformations.

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“…Amphiphilic synthetic polymer systems which form compact assemblies in water can adopt extended conformations in solvents of intermediate polarity, within which both hydrophobic and hydrophilic components energetically prefer the enthalpic contributions to solvation over the entropic restriction of compaction, or reverse micelles in solvents which invert typical aqueous behavior, leading hydrophilic components to invert together while hydrophobic moieties preferentially orient to an assembly's surface. This behavior has been experimentally observed for amphiphilic homopolymers with amphiphilic monomers, [ 14,15 ] as well as for heteropolymers with both hydrophobic and hydrophilic monomers, most well characterized for 2‐component copolymer systems. [ 16–20 ] The specific intramolecular interactions dictate how each polymer will adapt, with some systems maintaining monomer contacts in organic media compared to aqueous solvent due to strong intrachain associations which persist in the new environment.…”

Section: Introductionmentioning

confidence: 54%

Solvent Remodeling in Single‐Chain Amphiphilic Heteropolymer Systems

Hilburg

Alexander‐Katz

2022

Macromol. Rapid Commun.

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This work demonstrates the remodeling of single‐chain nanoparticles (SCNPs) upon a transition to organic solvent through molecular dynamics simulations. Methacrylate‐based random heteropolymers (RHPs), assembled via transient noncovalent linkages in water, have shown promise in an assortment of applications that harness their bio‐inspired properties. While their molecular behavior has been broadly characterized in aqueous environments, many newer applications include the use of organic solvent rather than bio‐mimetic conditions. The polymer assemblies, typically driven by the hydrophobic effect in water, are less well understood in nonaqueous solution. Here, a specific RHP system is examined which forms compact globular morphologies in highly polar or highly nonpolar environments while adopting extended conformations in solvents of intermediate polarity. The pivotal role of electrostatic interactions between charge groups in low dielectric mediums is also observed. Finally, high temperature anneal cycles are compared to room temperature transformations to illuminate barriers to remodeling upon environmental changes.

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Single-chain folding and self-assembling of amphiphilic polyethyleneglycol-modified fluorinated styrene homopolymers in water solution

Cited by 10 publications

References 52 publications

Self-Assembled Amphiphilic Fluorinated Random Copolymers for the Encapsulation and Release of the Hydrophobic Combretastatin A-4 Drug

Self-Assembled Amphiphilic Fluorinated Random Copolymers for the Encapsulation and Release of the Hydrophobic Combretastatin A-4 Drug

Thermoresponsive Reversible Unimer Micelles of Amphiphilic Fluorinated Copolymers

Solvent Remodeling in Single‐Chain Amphiphilic Heteropolymer Systems

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