Precipitation Polymerization Process Research Articles

Construction of biomimetic camouflaged neutrophil membrane nanoparticles for precise delivery and augmented glioma cancer treatment

Developing novel nanomedicine formulations that successfully penetrate the blood-brain barrier (BBB) to treat and diagnose glioma effectively is still a significant obstacle. This study presents the development of polymer nanogels camouflaged with macrophage membranes. The nanogels are loaded with manganese dioxide (MnO2) and carboplatin. They are designed for the treatment of glioma using a combination of chemotherapy and chemodynamic therapy (CDT). The precipitation polymerization process was used to create redox-responsive poly(caprolactone) (PCL) nanogels (NGs). These NGs were then loaded with MnO2 and physically encapsulated with carboplatin. The resulting nanogels had an average diameter of 102.52 nm and were covered with macrophage membranes to provide excellent stability. The developed NGs exhibit redox and pH responsiveness, releasing carboplatin and Mn(II) in a controlled manner. NGs may effectively deplete glutathione (GSH) in the tumour milieu. The Mn(II) generated in this process enhances the effectiveness of the loaded carboplatin by exerting its chemotherapeutic action and promoting the formation of reactive oxygen species to improve the efficiency of CDT. The results of our study show a very efficient and promising nanomedicine platform for the treatment and diagnosis of glioma, a type of cancer. This platform is self-adaptive, cooperative, and based on NG technology. Furthermore, this platform can potentially be used for other challenging types of cancer.

N,N-Dimethylaminoethyl methacrylate-based core/shell microgels loaded with silver nanoparticles for catalysis.

In this work, poly(styrene)@poly(N-isopropylmethacrylamide-co-2-(N,N-dimethyl)aminoethyl methacrylate [p(sty)@p(NIPMAM-DMAEMA)] core/shell microgel particles were produced by a two-step free-radical precipitation polymerization process. Ag nanoparticles were successfully embedded inside the sieves of a crosslinked network by using silver nitrate as the precursor salt and NaBH4 as the reductant. The synthesized pure and hybrid microgels were analyzed by various characterization tools, including Fourier transform infrared (FTIR) and UV-visible (UV-vis) spectroscopies, transmission electron microscopy (TEM) and dynamic light scattering (DLS). Results indicate the successful fabrication of spherical silver nanoparticles with diameters ranging from 10 to 15 nm within the sieves of the poly(styrene)@poly(N-isopropylmethacrylamide-co-2-(N,N-dimethyl)aminoethyl methacrylate) core/shell microgels, which have a hydrodynamic diameter of 155 ± 25 nm. The Ag nanomaterial exhibited long-term stability in the p(sty)@p(NIPMAM-DMAEMA) system due to the strong donor-acceptor relationship between the lone pair of the amide moiety in the polymer microgels and the Ag nanomaterial. The catalytic activity of the Ag-p(sty)@p(NIPMAM-DMAEMA) material was determined by performing the catalytic reduction of p-nitrophenol (4-NPh) as a model reaction under diverse concentrations of the catalyst. UV-vis spectrophotometry was used to check the progress of the reaction. The apparent rate constant (k app) was measured by applying the pseudo-first-order kinetics model. It was observed that k app increased with increasing catalyst dose, demonstrating occurrence of the reaction on the surface of the catalyst.

New Ion Selective Electrodes for Analysis of Metformin Based on Molecularly Imprinted Polymers

Metformin (MEF) imprinted polymer liquid electrodes arecreated using a precipitation polymerization process. The MEF served as a template for the creation of molecularly imprinted (MIP) materials using benzoyl peroxide (BPO) as an initiator, allyl methacrylate (AMA) crosslinkers, and glycidyl methacrylate (GMA) as a monomer. UtilizingDi-octyl-phthalate (DOPH) and di-butyl phthalate (DBPH) as plasticizers in a PVC matrix, the molecularly imprinted membranes arecreated. The reaction time is approximately 50 seconds, and the limits of detection for liquid electrodes, as determined by the calibration curves, are 55.6 to 58.4 mV/decadeat 5×10-5M and 8×10-5M respectively. The liquid electrodes demonstrated good selectivity over a variety of species and a consistent reaction when filled with a typical 0.1 M drug solution across the pH range of 1 to 11. Modern electrodes can detect MEF without the need for time-consuming pre-treatment procedures in pharmaceutical samples.

Removing of Anionic Dye from Aqueous Solutions by Adsorption Using of Multiwalled Carbon Nanotubes and Poly (Acrylonitrile-styrene) Impregnated with Activated Carbon

This paper presents an estimation of the adsorptive potential of multiwalled carbon nanotubes (MWCNTs) and modified poly (acrylonitrile-co-styrene) with activated carbon for the uptake of reactive red 35 (RR35) dye from aqueous solution by a batch system. MWCNT adsorbent was synthesized by encapsulation via in situ polymerization. The copolymer material of poly (acrylonitrile-styrene) P (AN-co-ST) was prepared in a ratio of 2:1 V/V by the precipitation polymerization process. The prepared composites’ properties were characterized by FTIR, SEM, Raman, mean particle size (PSA), and XRD analysis. The PSA of the copolymeric material was determined to be 450.5 and 994 nm for MWCNTs and P(AN-co-St)/AC, respectively. Moreover, the influences of different factors, for example pH (2–10), adsorbents dosage (0.005–0.04 g), contact time (5–120 min), initial dye concentration (10–50 mg L−1), and temperature (25–55 °C). The optimum values were determined to be 2 and 4 pH, 10 mg L−1 of RR35 dye, and 0.04 g of adsorbents at early contact time. Furthermore, the adsorption isotherm was studied using Langmuir, Freundlich, Tempkin, and Halsey models. Maximum capacity qmax for MWCNTS and P (AN-co-St)/AC was 256.41 and 30.30 mg g−1, respectively. The investigational kinetic study was appropriated well via a pseudo second-order model with a correlation coefficient around 0.99. Thermodynamic study displayed that the removal of RR35 is exothermic, a spontaneous and physisorption system. The adsorption efficiency reduced to around 54–55% of the RR35 after four cycles of reuse of the adsorbents at 120 min.

Fabrication of nickel-tagged magnetic imprinted polymeric network for the selective extraction of Ni(II) from the real aqueous samples.

A new nickel ion, magnetic imprinted polymer was fabricated through the precipitation polymerization process, using amine-functionalized silica-capped iron oxide particles as a core material, and 4-vinyl pyridine as complexing agent methacrylic acid as functional monomer. The resulted magnetic adsorbent was employed to eliminate toxic Ni2+ ions from industrial wastewater. The different parameters were optimized, such as pH, shaking speed, and adsorbent dose, to obtain the maximum adsorption capacity. The synthesized material showed high selectivity coefficient for Ni+2 ions in the presence of other competitive ions and followed pseudo-second-order kinetics and Langmuir isotherm. A good adsorption capacity of 158.73 mg g-1 was obtained at optimized pH 6 in the concentration of 5 mg L-1 nickel ions aqueous solution. The limit of detection, quantification, and the percent relative standard deviation was found to be 0.58, 1.93, and 3.4%. This proves the excellent performance of prepared magnetic Ni(II) ion-imprinted polymer for selective detoxification of Ni2+ ions from real aqueous samples. Due to tunable magnetic properties, the prepared MMIPs are highly selective and sensitive and highly porous in nature; due to excellent magnetic properties, there is no need for centrifugation. Just use external magnetic field, it has good reusability. Showing preparation of Ni (II) imprinted magnetic polymer.

Design and Testing of Efficient Mucus-Penetrating Nanogels-Pitfalls of Preclinical Testing and Lessons Learned.

Mucosal surfaces pose a challenging environment for efficient drug delivery. Various delivery strategies such as nanoparticles have been employed so far; yet, still yielding limited success. To address the need of efficient transmucosal drug delivery, this report presents the synthesis of novel disulfide-containing dendritic polyglycerol (dPG)-based nanogels and their preclinical testing. A bifunctional disulfide-containing linker is coupled to dPG to act as a macromolecular crosslinker for poly-N-isopropylacrylamide (PNIPAM) and poly-N-isopropylmethacrylamide (PNIPMAM) in a precipitation polymerization process. A systematic analysis of the polymerization reveals the importance of a careful polymer choice to yield mucus-degradable nanogels with diameters between 100 and 200nm, low polydispersity, and intact disulfide linkers. Absorption studies in porcine intestinal tissue and human bronchial epithelial models demonstrate that disulfide-containing nanogels are highly efficient in overcoming mucosal barriers. The nanogels efficiently degrade and deliver the anti-inflammatory biomacromolecule etanercept into epithelial tissues yielding local anti-inflammatory effects. Over the course of this work, several problems are encountered due to a limited availability of valid test systems for mucosal drug-delivery systems. Hence, this study also emphasizes how critical a combined and multifaceted approach is for the preclinical testing of mucosal drug-delivery systems, discusses potential pitfalls, and provides suggestions for solutions.

Thermomechanical investigations of polyurea microspheres

Polyurea is a thermoset elastomer with a wide range of implementations in industrial and biomechanical applications. In the past two decades, bulk polyurea was heavily investigated under different environmental, operating, and loading conditions. The further exploitation of the superior thermomechanical properties of polyurea necessitates the exploration of smaller length scales, e.g., microscales and nanoscales. Thus, the objective of this research was to fabricate cross-linked polyurea microspheres, which was hypothesized to inherit some of the properties of the bulk polyurea. While the production yield was found to be low, the resulting polyurea microspheres exhibit the hallmark characteristics of their bulk counterpart. The microspheres, fabricated by a modified precipitation polymerization process, were examined with a scanning electron microscope showing the microspheres to have a highly textured surface morphology and an average diameter of 2.4 ± 2.9 µm. Using FTIR spectroscopy and a thermogravimetric analyzer, the microspheres were found to have inherited the overall chemical structure and hygrothermal properties of bulk polyurea. Using an atomic force microscope, the elastic modulus of the microspheres was found to be 114.75 ± 40.71 MPa, four times stiffer than that of bulk polyurea. With such disparity of the elastic modulus, the polyurea microspheres can be used as a reinforcement phase in future polymer–polymer composites.

Nucleation Points: The Forgotten Parameter in the Synthesis of Hydrogel-Coated Gold Nanoparticles.

The implementation of gold-hydrogel core-shell nanomaterials in novel light-driven technologies requires the development of well-controlled and scalable synthesis protocols with precisely tunable properties. Herein, new insights are presented concerning the importance of using the concentration of gold cores as a control parameter in the seeded precipitation polymerization process to modulate—regardless of core size—relevant fabrication parameters such as encapsulation yield, particle size and shrinkage capacity. Controlling the number of nucleation points results in the facile tuning of the encapsulation process, with yields reaching 99% of gold cores even when using different core sizes at a given particle concentration. This demonstration is extended to the encapsulation of bimodal gold core mixtures with equally precise control on the encapsulation yield, suggesting that this principle could be extended to encapsulating cores composed of other materials. These findings could have a significant impact on the development of stimuli-responsive smart materials.

Synthesis of Polyampholyte Janus-like Microgels by Coacervation of Reactive Precursors in Precipitation Polymerization.

Controlling the distribution of ionizable groups of opposite charge in microgels is an extremely challenging task, which could open new pathways to design a new generation of stimuli‐responsive colloids. Herein, we report a straightforward approach for the synthesis of polyampholyte Janus‐like microgels, where ionizable groups of opposite charge are located on different sides of the colloidal network. This synthesis approach is based on the controlled self‐assembly of growing polyelectrolyte microgel precursors during the precipitation polymerization process. We confirmed the morphology of polyampholyte Janus‐like microgels and demonstrate that they are capable of responding quickly to changes in both pH and temperature in aqueous solutions.

Synthesis of Polyampholyte Janus‐like Microgels by Coacervation of Reactive Precursors in Precipitation Polymerization

AbstractControlling the distribution of ionizable groups of opposite charge in microgels is an extremely challenging task, which could open new pathways to design a new generation of stimuli‐responsive colloids. Herein, we report a straightforward approach for the synthesis of polyampholyte Janus‐like microgels, where ionizable groups of opposite charge are located on different sides of the colloidal network. This synthesis approach is based on the controlled self‐assembly of growing polyelectrolyte microgel precursors during the precipitation polymerization process. We confirmed the morphology of polyampholyte Janus‐like microgels and demonstrate that they are capable of responding quickly to changes in both pH and temperature in aqueous solutions.

Towards the realistic computer model of precipitation polymerization microgels

In this paper we propose a new method of coarse-grained computer simulations of the microgel formation in course of free radical precipitation polymerization. For the first time, we simulate the precipitation polymerization process from a dilute solution of initial components to a final microgel particle with coarse grained molecular dynamics, and compare it to the experimental data. We expect that our simulation studies of PNIPA-like microgels will be able to elucidate the subject of nucleation and growth kinetics and to describe in detail the network topology and structure. Performed computer simulations help to determine the characteristic phases of the growth process and show the necessity of prolongated synthesis for the formation of stable microgel particles. We demonstrate the important role of dangling ends in microgels, which occupy as much as 50% of its molecular mass and have previously unattended influence on the swelling behavior. The verification of the model is made by the comparison of collapse curves and structure factors between simulated and experimental systems, and high quality matching is achieved. This work could help to open new horizons in studies that require the knowledge of detailed and realistic structures of the microgel networks.

Thermally Sensitive Molecularly Imprinted Polymers on Mesoporous Silica Nanospheres: Preparation, Characterization, and Properties as Novel Adsorbents for Dichlorophen

Novel thermally responsive mesoporous silica nanosphere molecularly imprinted polymers (T-MMIPs) were prepared via a two-step precipitation polymerization process for selective adsorption and remov...

Synthesizing Vitamin E Molecularly Imprinted Polymers via Precipitation Polymerization

Molecularly imprinted polymers (MIPs) were prepared by the precipitation polymerization process, with vitamin E as the template molecule, ethylene glycol dimethacrylate as the cross-linker, and three different functional monomers, respectively. Adsorption experiments were conducted to investigate the performance of each MIP and compared to the nonimprinted polymers (NIPs). It was found that MIPs are superior to NIPs in general, with acrylamide-based MIP showing the best adsorption capacity of 38.8 mg·g–1 and an imprinting factor of 2.6. The optimal imprinting ratio and cross-linking ratio to be 1:5 and 5:1, respectively. The Freundlich equation was found superior to Langmuir to describe the adsorption isotherm data on the MIP/NIP. The adsorption of vitamin E on the MIP was found to be a heterogeneous process and consists of two mechanisms, which were confirmed by the analysis of the thermodynamic properties of the adsorption process.

Thermodynamic computational calculations for preparation 5-fluorouracil magnetic moleculary imprinted polymers and their application in controlled drug release

The interaction dynamics between drug-monomer-solvent is the backbone of the thermodynamic calculation in molecular imprinting process and the controlled drug release components. In this regards, thermodynamic computational calculation was used for preparation of magnetic molecular imprinted polymers (MMIPs) and their subsequent application in the controlled release of 5-fluorouracil in the cancer therapy. Cohesive energy density of components (CED)/resolution parameters (δd, δp, δH) are the important characteristic of desired profile and design. Accordingly, the calculations for choosing the best reactants were performed based on the utilization of chemical affinity profiles of Hansen method. Based on the thermodynamic computational calculations, 4-vinylpyridine (4-VP) and acrylic acid (AA) were chosen as optimal monomers to synthesize MMIPs. MMIPs were utilized as the pH responsive nanocarrier systems in the controlled release of 5-fluorouracil (5-FU) as an anti-cancer drug. At first, the Fe3O4 nanoparticles were functionalized by vinyl triethoxysilane moieties and finally, a MIP layer was synthesized on the surface of modified magnetic nanoparticles via precipitation polymerization process. The prepared polymer was characterized by FT-IR spectroscopy, scanning electron microscopy, thermogravimetric analysis (TGA), differential scanning calorimetric analysis (DSC), elemental analysis, and X-ray diffraction analysis. The results of high performance liquid chromatography analysis illustrated the controllable release of 5-FUin simulated body fluid at pH = 5.8 and pH = 7.4. At the end of 30 day, 90% and 80% of 5-FU released at pH 5.8 from 5-FU/4-VP and 5-FU/AA MMIPs, respectively, while these values at pH 7.4 were 70% and 65%, for 5-FU/4-VP and 5-FU/AA MMIPs, respectively. The preparation of these MMIPs was facile and fast and they are biocompatible.

Selective Solid Phase Extraction of Copper from Different Samples using Copper Ion-Imprinted Polymer

Ion imprinted polymer (IIP) for copper was synthesized for selective extraction of copper from different samples for analysis using flame atomic absorption spectrophotometry. In the synthesis of ion-imprinted polymer Cu(II) ion (template), 2,2'-bibyridine (ligand) and 4-vinylpyridine (functional monomer) which formed a complex through coordination with Cu(II) ion, ethylene glycol dimethacrylate (cross-linker) and 2,2'-azobisisobutyronitrile (initiator) were used. The ion-imprinted polymer and non-imprinted polymer (NIP) were synthesized via precipitation polymerization process. The synthesized polymers were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. Variables affecting the solid phase extraction of Cu(II) such as pH, initial Cu(II) concentration and time were studied in batch experiments. Quantitative retention of Cu(II) on IIP was achieved at pH 7. The IIP selectivity for copper ion extraction was higher as compared to NIP in the presence of other competing metal ions. The method was successfully applied to the determination of copper in multivitamin tablet, various natural water samples and industrial effluent.

Preparation of aromatic polyamide nanoparticles with multiple functional groups in mixed solvent solutions via a one-step precipitation polymerization

Aromatic polyamide nanoparticles with carbonyl chloride (COCl) and carboxyl (COOH) groups are prepared in a one-step precipitation polymerization process using a diamine and a diacid chloride, employing a combination of various solvents. The morphology, number of COCl groups introduced and molecular weight of the resulting particles are found to be greatly affected by the composition of the reaction solution. Pyridine acts primarily as a catalyst and also reduces the particle size and affects the incorporation of COCl groups. These groups originates from the diacid chloride and are present at the ends of polymeric chains. The solubility of the particles in the reaction solution is closely correlated with the time required for precipitation and significantly influences the particle formation mechanism. This in turn affects the molecular weight and the number of COCl groups.

β-Cyclodextrin-epichlorohydrin polymer/graphene oxide nanocomposite: preparation and characterization

In this study, we report a novel and simple technique to synthesize water-insoluble nanocomposite macromolecule composed of graphene oxide (GO) nanosheets and β-cyclodextrin (β-CD) polymer. These nanocomposites were synthesized by the one-pot precipitation polymerization process via polycondensation of β-CD with epichlorohydrin (ECH) in an aqueous suspension of GO under alkaline condition. The obtained β-CD polymer/GO (CDP-ECH/GO) were characterized by thermal gravimetry, differential scanning calorimetry, infrared and Raman spectroscopies, high-resolution solid state 13C NMR, X-ray diffraction, electron microscopy (both SEM and TEM), and energy dispersive spectroscopy. Furthermore, the mechanism of CDP-ECH/GO nanocomposites formation is also discussed depending on the type of mixing device that has been used during polymerization. The swelling ratio of the nanocomposites as well as their absorption properties toward methylene blue (MB), phenol (PN), 1-naphtol (1-NPH) and 2-naphtol (2-NPH) have been determined. Increasing the GO content in the nanocomposites results in an increase of the adsorption capacity of the materials.

Highly microporous free-radically generated polymeric materials using a novel contorted monomer

A novel, free-radically polymerizable, contorted monomer was synthesized in two steps from bisphenol A. In a simple precipitation polymerization process making use of solvent as a porogen, homopolymerization of this contorted monomer (SBI-DV) resulted in polymeric networks with surface areas as high as 850 m2/g and with SAmicro/SABET values as high as 0.65. Comparative DVB based polymeric networks produced under similar conditions had equally as high SABET but SAmicro/SABET values of 0.35. In addition, copolymeric networks were produced using varying molar monomer ratios of SBI-DV/DVB. The degree of microporosity in the resulting copolymeric networks correlated with the amount of SBI-DV used in their formation.

Highly crosslinked poly(ethyleneglycol dimethacrylate)-based microspheres via solvothermal precipitation polymerization in alcohol–water system

The preparation of highly crosslinked polymer microspheres through the polymerization reaction in an alcohol–water solution without any stabilizer is still a difficult task. Here, we first reported a facile preparation of monodispersed highly-crosslinked microspheres through the polymerization of ethyleneglycol dimethacrylate (EGDMA) in an alcohol–water solution in the presence of a small amount of hydrophilic comonomer with a high reactivity ratio in a sealed autoclave at above the boiling point of the solvent, which can be considered as a solvothermal precipitation polymerization process. The formation mechanism of the poly(ethyleneglycol dimethacrylate) (PEGDMA)-based microspheres involving an initial nucleation process and the grow process of the microspheres was proposed and confirmed by the composition and distribution of the hydrophilic comonomer in the oligomers and microspheres, which were analyzed by 1H and 13C CP-MAS solid NMR spectra, elemental mapping, and XPS. This work opens a new economic and environmental-friendly way to prepare highly-crosslinked functional PEGDMA-based microspheres.

Recyclable l-Proline Functional Nanoreactors with Temperature-Tuned Activity Based on Core–Shell Nanogels

Recyclable core-shell (CS) nanogels based on l-proline-containing hydrophobic cores with a thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) shell have been synthesized via a seeded precipitation polymerization process. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to verify the successful addition of the shell and investigate the thermoresponsive properties of the nanostructures. The catalytic activity of the nanogels was assessed in a model asymmetric aldol reaction, where an enhancement was observed with increasing temperature, attributed to the hydrophobic nature of the PNIPAM shell. However, when a nanogel was synthesized with core-shell morphology based on a gradient of cross-linking density in the corona (GS), a dramatic drop in activity was observed at elevated temperatures: the collapse of the outer, lightly cross-linked, "corona" polymer chains appears to block access to the catalytic core. High activity and enantioselectivity were maintained in a number of recovery and reuse cycles, highlighting the recycling potential of these catalytic nanostructures.