PEO PPO Research Articles

Effect of biosurfactants on the self-assembly behavior and drug encapsulation for branched block copolymers

For the past few years, block copolymers have attracted extensive attention in the field of drug delivery. In this work, the hyperbranched PEO-PPO block copolymer H1304 having the same PEO segments and PPO segments as the commercially available 4-branched block copolymer Tetronic1304 was synthesized. Compared with T1304, H1304 was characterized by lower cloud point, smaller critical micelle concentration (CMC), larger micellar size and better drug solubilization capacity. The effect of three biosurfactants lecithin (PC), alkyl glycogen (APG), sodium deoxycholate (NaDC) on the aggregation behavior of H1304 and T1304 were researched. Meanwhile, the solubilization and in vitro release properties of hydrophobic anticancer drug podophyllotoxin were also evaluated. The addition of PC or APG to form a mixed micelle reduced the cloud point and CMC, optimized the drug carrier characteristics. NaDC exhibited different effects due to its unique disclike surface structure. NaDC formed back-to-back aggregates, which interfered the self-assembly process of block copolymer and in turn caused variation of the copolymer micellar properties. The study of mixed systems consisting of biosurfactants and block copolymers will help to change the performance of copolymers in various pharmaceutical fields and contribute to the application of copolymers as drug carriers in drug delivery systems.

Indocyanine green within glycosylated polymeric micelles as potential image agents to map sentinel lymph nodes and breast cancer

The overall results presented in this work indicate the potential use of ICG-loaded PEO–PPO PMs as image probe agents to be employed in image-guided surgery, sentinel lymph node biopsy and breast cancer diagnostic imaging.

Facile fabrication of Pluronic-mediated copper nanoparticles using microwave techniques and their application as the photocatalysts for various organic dyes degradation

Pluronic-mediated copper nanoparticles (CuNPs) were fabricated using the reducing agent sodium borohydride in the micellar media of different Pluronics (L121, P123, and F127) using cost-effective microwave techniques. The microwave-irradiation used to create CuNPs has been optimized. All Pluronic-mediated CuNPs fabricated emit red light and have been thoroughly characterized using a range of advanced techniques. The results showed that the hydrophilic PEO and hydrophobic PPO parts of the Pluronic have a countable impact on the particle size and stability of the CuNPs. When compared to the other two Pluronic micellar media, the Pluronic F127-mediated CuNPs (CuNPsF7) performed better in terms of uniformity, size reduction, and stability. In this context, CuNPsF7 has been investigated as a powerful photocatalyst for the degradation of textile anionic (Congo red and methyl orange) and cationic (Methylene blue and rhodamine B) dyes. When compared to blank CuNPs, the results confirmed that the CuNPsF7 followed pseudo-first-order kinetics and significantly increased the rate and efficiency of dye degradation. In conclusion, the Pluronic-mediated CuNPs serve as potent photocatalysts to remove organic dyes in the treatment of waste water from textile industries.

Thermo‐responsive fluorine‐free foam stabilized by PEO–PPO–PEO triblock copolymer (EO)100(PO)65(EO)100 for pool fire suppression

AbstractResearch and development of novel fluorine‐free materials to replace fluorinated aqueous film‐forming foam (AFFF) are crucial for improving pool fire suppression performance and protecting the environment. In this study, we report the thermo‐responsive fluorine‐free foam stabilized by triblock PEO–PPO–PEO copolymers (EO)100(PO)65(EO)100 for pool fire suppression. Small‐angle X‐ray scattering (SAXS) and reflected light interferometric techniques are conducted to study the molecular self‐assembly in bulk and film thinning behavior, and the foaming kinetics of copolymer solution and thermophysical properties of the liquid foam are studied by dynamic surface tension and oscillatory rheology analysis. At room temperature, the amphipathic structure of PEO–PPO–PEO makes it possible to absorb at the air–liquid interface forming large‐scale liquid foams containing the mobile films with a detergent state. Upon heating to the surface cooling temperature of burning oil, the mobile films can be actively switched into mechanically strong films with rigid surfaces. The in situ switching of the two interfacial states leads to the significant enhancement of the foam stability, especially under the dual defoaming effects of heat and oil. What's more, it is observed that the confinement of organized copolymer micelles in the Plateau borders and micellar self‐layering in film confinement induce drainage delay of foam and film's stepwise thinning phenomenon, further increasing film thickness and enhancing the thermal stability of the foam. In standard fire‐fighting tests, it is proved that the burnback performance exhibited by thermo‐responsive copolymer foams is three times better than that for classical fluorine‐free foams and almost 1.5 times higher than that for commercial AFFF.

Influence of Polyether Backbone PEO–PPO on the Drug Release Behavior of Polyurea Xerogels

To evaluate possible structural changes and thermal stability of the polyurea unloaded and loaded with diclofenac sodium, polyurea networks based on polyetheramine containing polypropylene oxide (PPO) or polyethylene oxide (PEO) and hexamethylene diisocyanate trimer-HDI were synthesized. The formation of the network was controlled by sol-gel reactions, and the obtained materials were then characterized by different techniques (FTIR, XRD, TGA). Moreover, the amount of diclofenac released could be modulated as a function of time, studying the water absorption or swelling capacity, the cytotoxicity of the material and the amount of drug released. A choice was therefore made on the hydrophilicity of PEO- or PPO-based polyetheramine (with similar molecular weight), and the release profile was hereafter correlated with the water absorption by the PEO/PPO polyurea matrix. Links could finally be established between the release of diclofenac and the polyurea matrices properties, such as the nature of polymer (PEO/PPO) and the hydrophilicity (water uptake). Our objective here is to identify challenges and opportunities for the development of innovative functional biomaterials for health applications.

Molecular Structure and Co-solvent Distribution in PPO–PEO and Pluronic Micelles

Molecular Structure and Co-solvent Distribution in PPO–PEO and Pluronic Micelles

Dually responsive biodegradable drug releasing 3D printed structures

AbstractThe aim of this study was to develop temperature and pH‐responsive biodegradable 3D printed drug‐releasing constructs using the Digital Light Processing (DLP) printing technique. The printable molecules, named “inks” throughout this study, comprised polyethylene oxide–polypropylene oxide–polyethylene oxide (PEO–PPO–PEO) triblocks and acrylic acid (AAc) that rendered them reverse thermo‐responsive (RTR) and pH‐sensitive, respectively. Additionally, the inks' biodegradability was imparted to them by incorporating lactide (LA) and ε‐caprolactone (CL) units into their composition, while their printability was achieved by end‐capping them with 2‐Isocyanatoethyl methacrylate (IEMA). By fine tuning the LA/CL composition, a broad range of inks displaying different water absorption behavior, biodegradation as well as bovine serum albumin (BSA) release profiles at different conditions. All the hydrogels showed a fast and reversible swelling–deswelling response, as they fluctuated between pH 2.0 and pH 7.4 or between 10 and 37°C. The resultant hydrogels showed good water uptake capacity (6340%) at pH 7.4 and 10°C temperature. BSA release from the loaded 3D printed hydrogel showed a maximum (80.5%) at pH 7.4 and 10°C in comparison to pH 7.4 and 37°C (65%). The proposed dual responsive 3D printed biodegradable hydrogels objects will shed light as a drug carrier.

Concentration Threshold for Membrane Protection by PEO-PPO Block Copolymers with Variable Molecular Architectures.

Poloxamer 188, a poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer, protects cell membranes in several injury models. However, the nature of the copolymer/membrane interaction and the mechanism of membrane protection remain unknown. Systematic variations of the block copolymer architecture - including PPO-PEO-PPO triblocks and PPO-PEO diblocks - were used to probe the mechanism and evaluate the potential for alternative architectures to yield superior protection. To test the polymers, murine myoblasts were subjected to an osmotic stress, and membrane integrity was quantified by measuring lactate dehydrogenase (LDH) leakage. These experiments exposed a concentration threshold effect where all tested polymers reach 50% leakage of LDH compared to a non-treated buffer only control over a narrow concentration range of 0.8-4 μM. Differences in polymer protection at lower concentrations indicate that protection increases with the PPO-PEO-PPO molecular architecture and increasing hydrophobicity.

Room-temperature all-solid-state lithium metal batteries based on ultrathin polymeric electrolytes

Nanoconfinement of a PEO–PPO–PEO copolymer in an ultrathin PE membrane leads to high segmental mobility, which enables fast ion conduction.

T908 Polymeric Micelles Improved the Uptake of Sgc8-c Aptamer Probe in Tumor-Bearing Mice: A Co-Association Study between the Probe and Preformed Nanostructures.

Aptamers are oligonucleotides that have the characteristic of recognizing a target with high affinity and specificity. Based on our previous studies, the aptamer probe Sgc8-c-Alexa647 is a promising tool for molecular imaging of PTK7, which is an interesting biomarker in cancer. In order to improve the delivery of this probe as well as create a novel drug delivery nanosystem targeted to the PTK7 receptor, we evaluate the co-association between the probe and preformed nanostructures. In this work, preformed pegylated liposomes (PPL) and linear and branched pristine polymeric micelles (PMs), based on PEO–PPO–PEO triblock copolymers were used: poloxamer F127® and poloxamines T1307® and T908®. For it, Sgc8-c-Alexa647 and its co-association with the different nanostructures was exhaustively analyzed. DLS analysis showed nanometric sizes, and TEM and AFM showed notable differences between free- and co-associated probe. Likewise, all nanosystems were evaluated on A20 lymphoma cell line overexpressing PTK7, and the confocal microscopy images showed distinctness in cellular uptake. Finally, the biodistribution in BALB/c mice bearing lymphoma-tumor and pharmacokinetic study revealed an encouraging profile for T908-probe. All data obtained from this work suggested that PMs and, more specifically T908 ones, are good candidates to improve the pharmacokinetics and the tumor uptake of aptamer-based probes.

Structural Study of the Hydration of Lipid Membranes Upon Interaction With Mesoporous Supports Prepared by Standard Methods and/or X‐Ray Irradiation

Mesoporous materials feature ordered tailored structures with uniform pore sizes and highly accessible surface areas, making them an ideal host for functional organic molecules or nanoparticles for analytical and sensing applications. Moreover, as their porosity could be employed to deliver fluids, they could be suitable materials for nanofluidic devices. As a first step in this direction, we present a study of the hydration of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) model lipid membranes on solid mesoporous support. POPC was selected as it changes the structure upon hydration at room temperature. Mesoporous films were prepared using two different templating agents, Pluronic P123 (PEO–PPO–PEO triblock copolymer where PEO is polyethylene oxide and PPO is polypropylene oxide) and Brij 58 (C16H33(EO)20OH where EO is ethylene oxide), both following the conventional route and by X-ray irradiation via deep X-ray lithography technique and subsequent development. The same samples were additionally functionalized with a self-assembly monolayer (SAM) of (3-aminopropyl)triethoxysilane. For every film, the contact angle was measured. A time resolved structural study was conducted using in situ grazing incidence small-angle X-ray scattering while increasing the external humidity (RH), from 15 to 75% in a specially designed chamber. The measurements evidenced that the lipid membrane hydration on mesoporous films occurs at a lower humidity value with respect to POPC deposited on silicon substrates, demonstrating the possibility of using porosity to convey water from below. A different level of hydration was reached by using the mesoporous thin film prepared with conventional methods or the irradiated ones, or by functionalizing the film using the SAM strategy, meaning that the hydration can be partially selectively tuned. Therefore, mesoporous films can be employed as “interactive” sample holders with specimens deposited on them. Moreover, thanks to the possibility of patterning the films using deep X-ray lithography, devices for biological studies of increasing complexity by selectively functionalizing the mesopores with biofunctional SAMs could be designed and fabricated.

Synergistic effects in cross-linked blends of ion-conducting PEO-/PPO-based unsaturated polyesters

Ion-conductive unsaturated polyesters (UP) were synthesised from poly(ethylene oxide) (Xn = 9, 13, 22, 90) or poly(propylene oxide) (Xn = 7, 13, 20, 34, 68) and maleic anhydride. Subsequently, the polyesters were doped with LiClO4 and cross-linked with styrene using a redox initiator. For PEO-based polyesters, the minimum resistivity is found at an O/Li+ molar ratio of 50/1. In contrast, more lithium is required to reach the minimum when using PPO (O/Li+ = 10/1). Unlike the PEO-based polyesters, cross-linking of the PPO types gives rise to decreasing resistivities at increasing molecular weight. This correlates well with the transverse proton relaxation time determined by single-sided NMR, which is an indicator of the chain mobility. The cross-linking reaction of these UP with styrene exactly follows the predictions based on the copolymerisation parameters and is, therefore, not dependent on the ratio of styrene to UP double bonds as previously reported. Due to the opposing effects of the molecular weight on the ion conductivity of PEO- and PPO-based UP, 1:1 blends of short-chain PPO and long-chain PEO polyesters were cross-linked with styrene. The resulting networks showed a resistivity of 4 kΩ m (σ = 2.5∙10−4 S∙m−1), which is 5 times lower than the pure PEO and 3 times lower than the pure PPO materials.

Length of the Core Forming Block Effect on Fusion and Fission Dynamics at Equilibrium in PEO–PPO–PEO Triblock Copolymer Micelles in the Spherical Regime

The slow kinetics of block copolymer micelles make their dynamical pathways as important as the copolymer architecture in the self-assembly of nanostructures. Two types of dynamical pathways could ...

Quantifying Drug Cargo Partitioning in Block Copolymer Micelle Solutions

Understanding molecular partitioning in solution is crucial for the design of micelle-based formulations. We investigate PEO–PPO–PEO triblock copolymer micelles and their solubilization of three hy...

Influence of surfactant's polar head group charge on the self-assembly of three PEO–PPO–PEO triblock copolymers of widely varying hydrophobicity

The present study is based on the interaction between three polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) triblock copolymers namely Pluronics® L81, P84 and F88 (with same PPO Mol. Wt. but 10,40 and 80% PEO, respectively) and the ionic surfactants with 12-C chain but different polar head group charge viz. sodium dodecyl sulfate (SDS, anionic), dodecyl trimethylammonium bromide (DTAB, cationic) and N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (C12PS, zwitterionic) using plethora of techniques. The most hydrophobic Pluronic® L81 (cloud point, CP = 16.5 °C (5%w/w)) remains as molecularly dissolved below the CP and forms unstable vesicles close to CP, moderately hydrophobic, P84 (CP = 73.6 °C), remains molecularly dissolved below 15 °C and forms core-shell micelle above critical micelle temperature (CMT) and the highly hydrophilic F88 forms micelles at elevated temperatures. Micellization and dye solubilizing ability improved in the presence of salt (sodium chloride, NaCl). The presence of ionic surfactants leads to small sized surfactant rich micelles with progressive addition as confirmed by dynamic light scattering (DLS) and small angle neutron scattering (SANS). Amongst the three copolymers, P84 (Nagg ≈ 72) showed maximum solubility of dye and lowering power of CMC (CAC < 2 mM), hence SANS studies were limited to P84 and it was observed that SDS (Nagg ≈ 45) showed stronger interactions with P84 as compared to DTAB (Nagg ≈ 53) and C12PS (Nagg ≈ 83).

Effect of Pyrrolidinium Formate Ionic Liquid on Micellization of Direct and Reverse Pluronics in Aqueous Solutions.

The behavior of direct and reverse Pluronic, copolymer nonionic surfactants, poly(ethylene oxide) PEO, and poly(propylene oxide) PPO copolymers, in aqueous solution and in the pyrrolidinium formate ([pyrr][F]) ionic liquid, was investigated using Fourier transform infrared spectroscopy (FTIR spectroscopy). The study was performed for a fixed Pluronic concentration at room temperature. We showed that in aqueous solution, the spectra associated with the direct and reverse Pluronics are similar irrespective of the difference in length of the various PPO and PEO blocks, their positions and the PPO:PEO ratio. The study of those same Pluronics dissolved in a pure pyrrolidinium formate solution showed that the Pluronic types were soluble and that the micellization process can take place at room temperature. The interaction between the Pluronic 10R5 aqueous solutions and the [pyrr][F] for various ionic liquid volumes is reported.

One-Pot Synthesis of Theranostic Nanocapsules with Lanthanide Doped Nanoparticles

In this work, we have established a one-pot synthesis strategy to develop a new theranostic nanoplatform by simultaneously encapsulating Er3+, Yb3+ doped NaGdF4 upconverting nanoparticles (UCNPs) and photosensitizer zinc phthalocyanine (ZnPc) into polymeric micelle/silica nanocapsules. This approach consisted of interfacial templating condensation, using triblock copolymers, ethylene oxide)106(propylene oxide)70(ethylene oxide)106 (PEO-PPO-PEO), as the templating and protecting agent. The encapsulation followed a straightforward microemulsion mechanism in an aqueous environment of a near neutral pH. The surface hydrophobic nature of UCNPs is crucial for the success of encapsulation. To prevent the interaction between the hydrophobic OA ligands of UCNPs and the silanol groups of hydrated tetramethoxysilane (TMOS), we modified the previous procedure by tuning the addition sequence of TMOS. It allowed first to encapsulate UCNPs in PEO-PPO-PEO micelles, and then grow the silica shell within the micellar PPO core and PEO corona interface. The silica shell is incorporated for its chemical and mechanical stability, while the PEO corona confers additional steric stability to the nanocapsule. Using the modified strategy we successfully co-encapsulated UCNPs and ZnPc in one-pot, and minimized the distance between the two payloads to facilitate the energy transfer from UCNPs to ZnPc, as compared to conventional PS loading in the mesoporous silica coating. The integrated nanocapsule has an average hydrodynamic size of 85 nm with a low polydispersity index of 0.1, and demonstrates excellent colloidal stability, biocompatibility, as well as enhanced negative contrast for T2-weighted imaging and photodynamic therapy. The latter is obtained through indirect excitation of co-encapsulated ZnPc by UCNPs, resulting in singlet oxygen generation and in vitro eradication of BT474 breast cancer cells. Overall, the presented one-pot approach shined light on the co-encapsulation of OA capped inorganic UCNPs with hydrophobic photosensitizers, constituting an important step forward in the surface engineering of UCNPs, as well as upconversion based photodynamic therapy delivery systems.

Spatial Distribution of PEO-PPO-PEO Block Copolymer and PEO Homopolymer in Lipid Bilayers.

Maintaining the integrity of cell membranes is indispensable for cellular viability. Poloxamer 188 (P188), a poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer with a number-average molecular weight of 8700 g/mol and containing 80% by mass PEO, protects cell membranes from various external injuries and has the potential to be used as a therapeutic agent in diverse applications. The membrane protection mechanism associated with P188 is intimately connected with how this block copolymer interacts with the lipid bilayer, the main component of a cell membrane. Here, we report the distribution of P188 in a model lipid bilayer comprising 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) using neutron reflectivity (NR) and atomic force microscopy (AFM). We also investigated the association of a PEO homopolymer (PEO8.4K; Mn = 8400 g/mol) that does not protect living cell membranes. These experiments were conducted following incubation of a 4.5 mmol/L polymer solution in a buffer that mimics physiological conditions with supported POPC bilayer membranes followed by washing with the aqueous medium. In contrast to previous reports, which dealt with P188 and PEO in salt-free solutions, both P188 and PEO8.4K penetrate into the inner portion of the lipid bilayer as revealed by NR, with approximately 30% by volume occupancy across the membrane without loss of bilayer structural integrity. These results indicate that PEO is the chemical moiety that principally drives P188 binding to bilayer membranes. No defects or phase-separated domains were observed in either P188- or PEO8.4K-incubated lipid bilayers when examined by AFM, indicating that polymer chains mingle homogeneously with lipid molecules in the bilayer. Remarkably, the breakthrough force required for penetration of the AFM tip through the bilayer membrane is unaffected by the presence of the large amount of P188 and PEO8.4K.

Dehydrating Heavy Crude Oils with New Amphoteric Block Bipolymers

A series of new amphoteric block bipolymers were prepared by the functionalization of PEO–PPO–PEO block bipolymers with a terminal tertiary amine and subsequently, with acrylic acid derivatives by ...

Synthesis, aggregation and adsorption behaviour of a thermoresponsive pentablock copolymer

AbstractPoly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) triblock copolymer (Pluronic F127) was modified by introducing poly(N‐isopropylacrylamide) (PNIPAM) at both the PEO ends, and the pentablock copolymer (PNIPAM41–F127–PNIPAM41, PN41) so prepared was characterized using gel permeation chromatography and 1H NMR spectroscopy. The degree of polymerization of NIPAM blocks at the two ends was 41. The solution behaviour and microstructure of PN41 aggregates in water were examined using UV–visible spectroscopy, micro‐differential scanning calorimetry and small‐angle neutron scattering (SANS) and compared with F127. Two lower critical solution temperatures (LCSTs) were observed for the pentablock copolymer, corresponding to PPO and PNIPAM blocks, respectively. The adsorption of PN41 on thiol‐grafted hydrophobic gold surfaces at various temperatures was investigated using a quartz crystal microbalance. It was found that the adsorption behaviour and mechanism of PN41 were mainly determined by the interactions of the pentablock copolymers with different chain conformations in dilute aqueous solutions at various temperatures. SANS measurements were used to determine the temperature‐dependent structural evolution of polymer micelles in aqueous solution. A NOESY study revealed that above the LSCT of PNIPAM, the interaction of PPO and PNIPAM protons increases and the distance between PPO and PNIPAM decreases. © 2019 Society of Chemical Industry