Copolymer Nanoparticles Research Articles

A Simple Route to Aqueous Suspensions of Degradable Copolymer Nanoparticles Based on Radical Ring-Opening Polymerization-Induced Self-Assembly (rROPISA)

A Simple Route to Aqueous Suspensions of Degradable Copolymer Nanoparticles Based on Radical Ring-Opening Polymerization-Induced Self-Assembly (rROPISA)

Polymer-Inorganic Crystalline Nanocomposite Materials via Nanoparticle Occlusion.

Efficient occlusion of guest nanoparticles into host single crystals opens up a straightforward and versatile way to construct functional crystalline nanocomposites. This new technique has attracted increasing research interest because it enables the composition, structure, and properties of the resulting nanocomposites to be well-controlled. This review aims to provide a comprehensive summary of nanoparticle occlusion within inorganic crystals. First, recently-developed strategies for the occlusion of various colloidal particles (e.g., diblock copolymer nanoparticles, polymer-modified inorganic nanoparticles, oil droplets, etc.) within host crystals (e.g., CaCO3 , ZnO, or ZIF-8) are summarized. Second, new results pertaining to spatially-controlled occlusion and the physical mechanism of nanoparticle occlusion are briefly discussed. Finally, the physicochemical properties and potential applications of various functional nanocomposite crystals constructed via nanoparticle occlusion are highlighted and the perspective on the likely future for this research topic is also offered.

Anticancer Biosurfactant-Loaded PLA-PEG Nanoparticles Induce Apoptosis in Human MDA-MB-231 Breast Cancer Cells.

Despite various advancements in cancer therapies, treating cancer efficiently without side effects is still a major concern for researchers. Anticancer drugs from natural sources need to be explored as a replacement for chemo drugs to overcome their limitations. In our previous studies, isolation, characterization, and anticancer properties of a novel biosurfactant from Candida parapsilosis were reported. In this study, we report the cytotoxicity of the polymeric nanoparticles of this novel biosurfactant toward breast cancer cells. Biosurfactant-encapsulated polymeric nanoparticles of polylactic acid–poly(ethylene glycol) (PLA–PEG) copolymers were synthesized by the double emulsion solvent evaporation method. Folic acid (FA) was used as a targeting ligand to actively deliver the anticancer cargo to the cancer site. The encapsulation efficiency of nanoparticles was observed as 84.9%, and Fickian diffusion was observed as a kinetic model for the release of biosurfactant from nanoparticles. The controlled delivery of the biosurfactant was noticed when encapsulated in PLA–PEG copolymer nanoparticles. Additionally, it was observed that FA enhanced the uptake and cytotoxicity of biosurfactant-loaded nanoparticles in MDA-MB-231 cancer cells compared to biosurfactant-loaded plain nanoparticles. Induction of apoptosis was observed in cancer cells by these nanoparticles. We explore a potential anticancer agent that can be further analyzed for its efficiency and can be used as an alternative tool.

Mechanism of poly(lactic acid-glycolic acid) (PLGA) copolymer nanoparticles in enhancing cytotoxicity against occurrence and development of lung cancer metastasis

Poly lactic acid-glycolic acid copolymer (PLGA) plays a critical role in inducing tumor cells apoptosis. However, the solubility of the compound itself puts a limit on its use value in treatment of tumor. In this study, we used PLGA combined with nanoparticles as a strategy for metastatic tumor of lung cancer. We evaluated the biological effect of PLGA nanoparticles on enhancing cytotoxicity and its anti-tumor effect against metastasis tumor of lung cancer. Confocal microscope was used to detect the transfection efficiency of tumor cells. PLGA and PLGA-cored nanoparticles (PLGA AC-NPs) were used to interfere with proliferation and apoptosis of metastatic tumor cell line from lung cancer and flow cytometry was used to explore its effect. Furthermore, PLGA and PLGA AC-NPs were injected into the chest of lung cancer mice for treatment. Cell proliferation and apoptosis were detected through measurement of tumor volume, immunohistochemistry (IHC) and Westernblot protein analysis. It was found that, PLGA AC-NPs significantly enhanced cell uptake while PLGA ACNPs regulated tumor by inhibiting cell proliferation and promoting apoptosis. It was also observed in vivo transplanted tumor model that the growth of metastatic tumor of lung cancer was inhibited significantly by NGO-PEG-PEI/Cer, while proliferation and accelerated apoptosis were also slowed down. PLGA AC-NPs can inhibit tumor growth by promoting apoptosis and inhibiting further proliferation of tumor cells.

Self-Organized Nanoparticles of Random and Block Copolymers of Sodium 2-(Acrylamido)-2-methyl-1-propanesulfonate and Sodium 11-(Acrylamido)undecanoate as Safe and Effective Zika Virus Inhibitors.

A series of anionic homopolymers, poly(sodium 2-(acrylamido)-2-methyl-1-propanesulfonate) (PAMPS) and amphiphilic copolymers of AMPS and sodium 11-(acrylamido)undecanoate (AaU), both block (PAMPS75-b-PAaUn), and random (P(AMPSm-co-AaUn)), were synthesized and their antiviral activity against Zika virus (ZIKV) was evaluated. Interestingly, while the homopolymers showed limited antiviral activity, the copolymers are very efficient antivirals. This observation was explained considering that under the conditions relevant to the biological experiments (pH 7.4 PBS buffer) the macromolecules of these copolymers exist as negatively charged (zeta potential about −25 mV) nanoparticles (4–12 nm) due to their self-organization. They inhibit the ZIKV replication cycle by binding to the cell surface and thereby blocking virus attachment to host cells. Considering good solubility in aqueous media, low toxicity, and high selectivity index (SI) of the PAMPS-b-PAaU copolymers, they can be considered promising agents against ZIKV infections.

Bortezomib-Encapsulated Dual Responsive Copolymeric Nanoparticles for Gallbladder Cancer Targeted Therapy.

Gallbladder cancer (GBC) is a rare but the most malignant type of biliary tract tumor. It is usually diagnosed at an advanced stage and conventional treatments are unsatisfactory. As a proteasome inhibitor, bortezomib (BTZ) exhibits excellent antitumor ability in GBC. However, the long‐term treatment efficacy is limited by its resistance, poor stability, and high toxicity. Herein, BTZ‐encapsulated pH‐responsive copolymeric nanoparticles with estrone (ES‐NP(BTZ; Ce6)) for GBC‐specific targeted therapy is reported. Due to the high estrogen receptor expression in GBC, ES‐NP(BTZ; Ce6) can rapidly enter the cells and accumulate near the nucleus via ES‐mediated endocytosis. Under acidic tumor microenvironment (TME) and 808 nm laser irradiation, BTZ is released and ROS is generated by Ce6 to destroy the “bounce‐back” response pathway proteins, such as DDI2 and p97, which can effectively inhibit proteasomes and increase apoptosis. Compared to the traditional treatment using BTZ monotherapy, ES‐NP(BTZ; Ce6) can significantly impede disease progression at lower BTZ concentrations and improve its resistance. Moreover, ES‐NP(BTZ; Ce6) demonstrates similar antitumor abilities in patient‐derived xenograft animal models and five other types of solid tumor cells, revealing its potential as a broad‐spectrum antitumor formulation.

Design and characterization of high‐performance epoxy adhesive with block copolymer and alumina nanoparticles in aluminum‐aluminum bonded joints: Mechanical properties, lap shear strength, and thermal stability

AbstractIn this research, phenolic resin and poly (butyl‐acrylate‐block‐styrene) copolymer were used in the formulation of epoxy adhesive to improve its thermal stability and toughness. Also, in order to improve the mechanical properties such as the modulus and tensile strength, aluminum oxide nanoparticles (NPs) were added to the epoxy based resin. Effects of different factors such as percent contents of phenolic resin, toughening agent, and aluminum oxide NPs on the microstructure, mechanical properties, and thermal stability of the epoxy‐based adhesives were investigated. Thermogravimetric analysis, Fourier transform infrared spectroscopy, and field‐emission scanning electron microscopy were used to investigate the thermal, mechanical, and morphological properties of the prepared epoxy adhesive samples. In addition, the curing kinetics of the optimal specimens was studied based on differential scanning calorimetry (DSC). The experimental results indicated that the phenolic decreased strength of dog‐bone samples, while increased the adhesion strength in metal‐to‐metal single‐lap strength. On the other hand, addition of block‐copolymers as toughening agent led to a consistent decrease in the modulus as well as increasing the tensile strength. Also, results of single‐lap strength tests showed that, in the optimal quad system, the four components exhibit synergetic effects and show a single‐lap strength that is 152% higher than that of pure epoxy. The DSC analysis indicated that the presence of alumina NPs and block‐copolymers tend to reduce the initial curing temperature while increasing the curing reaction heat.

Study of antimycobacterial, cytotoxic, and mutagenic potential of polymeric nanoparticles of copper (II) complex

ABSTRACT This study aimed to encapsulate and characterize a potential anti-tuberculosis copper complex (CuCl2(INH)2.H2O:I1) into polymeric nanoparticles (PNs) of polymethacrylate copolymers (Eudragit®, Eu) developed by nanoprecipitation method. NE30D, S100 and, E100 polymers were tested. The physicochemical characterizations were performed by DLS, TEM, FTIR, encapsulation efficiency and, in vitro release studies. Encapsulation of I1 in PN-NE30D, PN-E100, and PN-S100 was 26.3%, 94.5%, 22.6%, respectively. The particle size and zeta potential were 82.3 nm and -24.5 mV for PNs-NE30D, 304.4 nm and +18.7 mV for PNs-E100, and 517.9 nm and -6.9 mV for PNs-S100, respectively. All PDIs were under 0.5. The formulations showed a I1 controlled release at alkaline pH with 29.7% from PNs-NE30D, 7.9% from PNs-E100 and, 28.1% from PNs-S100 at 1 h incubation. PNs were stable for at least 3 months. Particularly, PNs-NE30D demonstrated moderate inhibition of M. tuberculosis and low cytotoxic activity. None of the PNs induced mutagenicity.

Adsorption of sterically-stabilized diblock copolymer nanoparticles at the oil-water interface: effect of charged end-groups on interfacial rheology.

The RAFT aqueous emulsion polymerization of either methyl methacrylate (MMA) or benzyl methacrylate (BzMA) is conducted at 70 °C using poly(glycerol monomethacrylate) (PGMA) as a water-soluble precursor to produce sterically-stabilized diblock copolymer nanoparticles of approximately 30 nm diameter. Carboxylic acid- or morpholine-functional RAFT agents are employed to confer anionic or cationic functionality at the ends of the PGMA stabilizer chains, with a neutral RAFT agent being used as a control. Thus the electrophoretic footprint of such minimally-charged model nanoparticles can be adjusted simply by varying the solution pH. Giant (mm-sized) aqueous droplets containing such nanoparticles are then grown within a continuous phase of n-dodecane and a series of interfacial rheology measurements are conducted. The interfacial tension between the aqueous phase and n-dodecane is strongly dependent on the charge of the terminal group on the stabilizer chains. More specifically, neutral nanoparticles produce a significantly lower interfacial tension than either cationic or anionic nanoparticles. Moreover, adsorption of neutral nanoparticles at the n-dodecane-water interface produces higher interfacial elastic moduli than that observed for charged nanoparticles. This is because neutral nanoparticles can adsorb at much higher surface packing densities owing to the absence of electrostatic repulsive forces in this case.

Kinetically stable sub-50 nm fluorescent block copolymer nanoparticles via photomediated RAFT dispersion polymerization for cellular imaging.

Self-assembled block copolymer nanoparticles (NPs) have emerged as major potential nanoscale vehicles for fluorescence bioimaging. The preparation of NPs with high yields possessing high kinetic stability to prevent the leakage of fluorophore molecules is crucial to their practical implementation. Here, we report a photomediated RAFT polymerization-induced self-assembly (PISA) yielding uniform and nanosized poly((oligo(ethylene glycol) acrylate)-block-poly(benzyl acrylate) particles (POEGA-b-PBzA) with a concentration of 22 wt%, over 20 times more than with micellization and nanoprecipitation. The spherical diblock copolymer nanoparticles have an average size of 10-50 nm controllable through the degree of polymerization of the stabilizing POEGA block. Subsequent dialysis against water and swelling with Nile red solution led to highly stable fluorescent NPs able to withstand the changes in concentration, ionic strength, pH or temperature. A PBzA/water interfacial tension of 48.6 mN m-1 hinders the exchange between copolymer chains, resulting in the trapping of NPs in a "kinetically frozen" state responsible for high stability. A spectroscopic study combining fluorescence and UV-vis absorption agrees with a preferential distribution of fluorophores in the outer POEGEA shell despite its hydrophobic nature. Nile red-doped POEGA-b-PBzA micelles without initiator residues and unimers but with high structural stability turn out to be noncytotoxic, and can be used for the optical imaging of cells. Real-time confocal fluorescence microscopy shows a fast cellular uptake using C2C12 cell lines in minutes, and a preferential localization in the perinuclear region, in particular in the vesicles.

Pyridine-functional diblock copolymer nanoparticles synthesized via RAFT-mediated polymerization-induced self-assembly: effect of solution pH.

Polymerization-induced self-assembly (PISA) via reversible addition-fragmentation chain transfer (RAFT) polymerization has become widely recognized as a versatile and efficient strategy to prepare complex block copolymer nanoparticles with controlled morphology, size, and surface functionality. In this article, we report the preparation of cationic sterically-stabilized poly(2-vinylpyridine)-poly(benzyl methacrylate) (P2VP-PBzMA) diblock copolymer nanoparticles via RAFT-mediated PISA under aqueous emulsion polymerization conditions. It is demonstrated that the solution pH during PISA has a dramatic effect on the resulting P2VP-PBzMA nanoparticles, as judged by dynamic light scattering (DLS), disc centrifuge photosedimentometry (DCP) and transmission electron microscopy (TEM). Varying the solution pH results in the P2VP stabilizer having different solubilities due to protonation/deprotonation of the pyridine groups. This allows P2VP-PBzMA nanoparticles with tunable diameters to be prepared by altering the DP of the stabilizer (P2VP) and/or core-forming block (PBzMA), or simply by changing the solution pH for a fixed copolymer composition. For example, P2VP-PBzMA nanoparticles with larger diameters can be obtained at higher solution pH as the protonation degree of the P2VP stabilizer has a large effect on both the aggregation of polymer chains during the PISA process, and the resulting behavior of the diblock copolymer nanoparticles. Changing the dispersion pH post-polymerization has a relatively limited effect on particle diameter. Furthermore, aqueous electrophoresis studies indicate that these P2VP-PBzMA nanoparticles had good colloidal stability and high cationic charge (>30 mV) below pH 5 and can be dispersed readily over a wide pH range.

The Significance of PAX8-PPARγ Expression in Thyroid Cancer and the Application of a PAX8-PPARγ-Targeted Ultrasound Contrast Agent in the Early Diagnosis of Thyroid Cancer.

Objective To investigate the significance of PAX8-PPARγ expression in thyroid cancer and the application of a PAX8-PPARγ-targeted ultrasound contrast agent in the early diagnosis of thyroid cancer. Methods In this study, the expression of PAX8-PPARγ in thyroid cancer tissues, paracancer groups, and normal thyroid tissues was detected by western and immunohistochemical techniques; the effects of PAX8-PPARγ expression inhibition on thyroid cancer cell growth, clonogenic ability, and antiapoptosis were examined. The terminal carboxylactic acid/hydroxyacetic acid copolymer (PLGA-COOH) nanoparticles were prepared by the double emulsification solvent volatilization method. The in vitro cytotoxicity of the targeted contrast agent was detected by MTS and other methods; LD50 was used to evaluate its short-term in vivo toxicity after intraperitoneal injection in mice. Results PAX8-PPARγ expression was significantly increased in thyroid cancer tissues, and the expression level of PAX8-PPARγ was closely correlated with TNM staging and lymph node metastasis (P < 0.05). In addition, PAX8-PPARγ was also expressed at high levels in thyroid cancer cell lines relative to normal thyroid cells. MTS experiments showed that the PAX8-PPARγ-targeted ultrasound nanocontrast agent had no significant toxic side effects on thyroid cells; countess observed that the contrast agent had no effect on cell survival and mortality; the LD50 assay showed that the targeted contrast agent had a wide safety range. Western blot showed the expression of caspase-3, BAX, and Bcl-2 in thyroid cancer cells, indicating that the nanocontrast agent has a good biosafety. In vitro targeting experiments showed that there were more nanospheres aggregated around the cells in the targeted contrast group. In vivo targeting imaging of nude mice revealed that the ultrasound signal was significantly enhanced in the targeted group compared with the nontargeted group after 20 min of LIFU irradiation. Conclusion PAX8-PPARγ overexpression in thyroid cancer cell lines and thyroid cancer tissues promoted the proliferation and antiapoptotic ability of thyroid cancer cells and promoted the tumorigenic ability in nude mice in vivo. We successfully prepared a PAX8-PPARγ-targeted ultrasound nanocontrast agent, which has regular morphology, uniform size, and high stability, and its liquid-gas phase change can be promoted at lower temperature. Therefore, this contrast agent can achieve US-targeted imaging and temperature phase transition function, and may have enhanced ultrasound imaging potential.

RAFT aqueous dispersion polymerization of 4-hydroxybutyl acrylate: effect of end-group ionization on the formation and colloidal stability of sterically-stabilized diblock copolymer nanoparticles

Poly(2-hydroxyethyl acrylate)-poly(4-hydroxybutyl acrylate) nano-objects are prepared by aqueous polymerization-induced self-assembly (PISA) using an ionic RAFT agent.

Synthesis and derivatization of epoxy-functional sterically-stabilized diblock copolymer spheres in non-polar media: does the spatial location of the epoxy groups matter?

Epoxy-functional sterically-stabilized diblock copolymer nanoparticles are prepared via PISA in mineral oil and then derivatized using various reagents and reaction conditions.

A photothermally triggered one-component shape memory polymer material prepared by cross-linking porphyrin-based amphiphilic copolymer self-assemblies.

Photothermally triggered shape memory polymer materials are usually prepared by dispersing photothermally responsive fillers or compounds into shape memory polymer matrixes through physical blending, while the migration and non-biodegradability of the fillers limit their potential applications (e.g., in the biomedical field). Here, we synthesized a new type of porphyrin-based amphiphilic random copolymer bearing a reactive moiety of carbonyl group by co-polymerizing methyl methacrylate (MMA), butyl acrylate (BA), diacetone acrylamide (DAAM), acrylic acid (AA) and double-bonded vinyl porphyrin monomers, followed by induced self-assembly in aqueous solution to give rise to amphiphilic random copolymer nanoparticles. The nanoparticles were further crosslinked by means of adipic dihydrazide (ADH) to fabricate the photothermally triggered one-component shape memory polymer material. Compared with the most-studied multi-phase/multi-component shape memory polymer materials, the porphyrin moiety, playing the role of a photo-to-heat converter, covalently bonded into the polymer structure would certainly make it more homogeneous and more stable in principle.

Empagliflozin Loaded Polyethylene Glycol/Alginate Co-Polymeric Nanoparticles for the Treatment of Hepatic Cancer

Empagliflozin Loaded Polyethylene Glycol/Alginate Co-Polymeric Nanoparticles for the Treatment of Hepatic Cancer

Heat-induced spontaneous and damage-free separation of transparent polymer thin films based on clickable decomposition of pyrolytic core-shell nanocapsules

The automatic and damage-free manipulation for efficient separation of polymer thin films from various substrates has received growing interests in a broad range of applications from electronic devices to optical films because it can realize the innovative recycling and on-demand spontaneous detachment of scarce and valuable materials. Herein, we demonstrate a spontaneous and damage-free separation methodology for transparent polymer thin films based on the heat-induced microbubble generation from pyrolytic core-shell nanocapsules at the interface between the substrate and the thin film. The pyrolytic polymer nanocapsules were fabricated by encapsulating a latent gas-forming agent of benzenesulfonyl hydrazine in the crosslinked copolymer nanoparticle comprising polyacrylonitrile and poly(methyl methacrylate). The heat-induced clickable decomposition of pyrolytic core-shell nanocapsules generated a significant number of microbubbles inside the thin film, thereby inducing instantaneous and effortless detachment of the transparent film from substrate. The fabricated polymer thin films embedded with a small number of pyrolytic polymer nanocapsules afforded an excellent debonding performance with a maximum efficiency of 93.4% after short thermal treatment compared to that of the pristine thin films, simultaneously maintaining a remarkable optical clarity of about 99% and a high initial adhesion strength with a maximum of approximately 22 kgf cm−2.

Production of water-based mud for drilling operation application

A successful drilling operation is heavily dependent on the effectiveness of the drilling fluid's design in use. This study attempts to evaluate the rheological and filtration properties of water-based drilling mud (WBDM) upon the addition of Stearyl Acrylate-Behenyl Acrylate (SABA) copolymer, silicon dioxide (SiO2), and nickel (III) oxide (Ni2O3) nanoparticles. This SABA copolymer-nanofluid was prepared by dissolving the nanofluid in a SABA polymer solution and homogenizing it using ultrasonication. The properties were studied using mud balance, viscometer, and low-pressure low-temperature (LPLT) filter press. The rheological and filtration properties of SABA copolymer were found to imply that it could improve drilling fluid performance. However, the addition of nanoparticles gave a better performance of rheological and filtration properties on WBDM. SABA copolymer with 5000 ppm concentration shows the best performance due to showing the highest viscosity compared to basic drilling fluid. Also, the addition of 800 ppm of Ni2O3 concentration into 5000 ppm of SABA shows the lowest fluid losses. The experimental results indicate that SABA copolymer shows a great potential application and the addition of nanoparticles shows that nanotechnology has a lot of potentials to improve WBM performance

Effects of water-cement ratio and superplasticizer dosage on mechanical and microstructure formation of styrene-butyl acrylate copolymer concrete

The interaction between nanoparticles of Styrene-Butyl Acrylate latex and cement particles with various water-cement and superplasticizers-cement ratios during the hydration process has been investigated to achieve the best chemical combination of the materials for enhancing the mechanical properties and workability of the concrete. Analyses and experimental results have shown that the adhesive properties of Styrene Butyl Acrylate (SBA) copolymer latex along with an appropriate percentage of superplasticizers promote the performances of interlayer bonding of concrete. The compressive, splitting, and flexural strengths of specimens have been studied and the formations of the microstructures by the implementation of FESEM, EDX, XRD, FTIR, TEM, and DLS, have been analyzed. The obtained results show the considerable enhancement in the structural behavior of the copolymer-modified concrete in comparison with the control samples by creating cohesive microstructures in the presence of the copolymer. Appropriate water-cement ratio and superplasticizers were selected to study the efficient distribution of the copolymer nanoparticles throughout the cement matrix by the implementation of the FESEM and EDX analyses. The constructed polymer bridges and films between layers of Ca(OH)2 crystals have yielded to the formation of an internal cohesive strong microstructure. Also, XRD and FTIR results indicate that the stability and formation of ettringite have been enhanced by the development of calcium aluminate reaction with SBA copolymer. In the cement pore solution, the chemical interaction between nanoparticles, and Ca2+, the copolymer nanoparticles adsorption on cement paste were applied and the enhanced microstructure of the concrete was obtained.

Photo-Responsivity Improvement of Photo-Mobile Polymers Actuators Based on a Novel LCs/Azobenzene Copolymer and ZnO Nanoparticles Network.

The efficiency of photomobile polymers (PMP) in the conversion of light into mechanical work plays a fundamental role in achieving cutting-edge innovation in the development of novel applications ranging from energy harvesting to sensor approaches. Because of their photochromic properties, azobenzene monomers have been shown to be an efficient material for the preparation of PMPs with appropriate photoresponsivity. Upon integration of the azobenzene molecules as moieties into a polymer, they act as an engine, allowing fast movements of up to 50 Hz. In this work we show a promising approach for integrating ZnO nanoparticles into a liquid crystalline polymer network. The addition of such nanoparticles allows the trapping of incoming light, which acts as diffusive points in the polymer matrix. We characterized the achieved nanocomposite material in terms of thermomechanical and optical properties and finally demonstrated that the doped PMP was better performing that the undoped PMP film.