Amine-functionalized Polystyrene Research Articles

Nanoparticle Surfactants at Complex Emulsion Interfaces.

Using nanoparticle surfactants to stabilize the liquid-liquid interface has attracted significant attention for developing all-liquid constructs including emulsions and liquid devices. Here, an efficient strategy is demonstrated to stabilize complex emulsions that consist of multiphase droplets by using the co-assembly between the cellulose nanocrystal and amine-functionalized polystyrene. Cellulose nanocrystal surfactants (CNCSs) form and assembly in situ at the specified area of emulsion interface, showing a unique pH responsiveness due to their dynamic nature and allowing the reconfiguration of complex emulsion from encapsulated to Janus structures. Such complex emulsions can be further used as the templates to fabricate polymeric particles with hollow, semi-spherical, and spherical shapes on large scale. These findings establish a promising platform for designing intelligent soft matter that can be used in microreactors, sensors, and anisotropic materials.

Rapid and facile detection of PBTC antiscalant using functionalized polystyrene nanoparticles and latex agglutination

Organophosphate-based compounds, particularly 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), have been crucial in circulating cooling systems and wastewater treatments as corrosion inhibitors preventing scale deposits in industrial facilities. Employing the reagent within its optimum concentration range is essential for effective performance, minimizing costs and environmental impacts. However, measuring PBTC separately can be challenging due to its functional groups’ similarity to other common molecules found in natural water, necessitating complex procedures. In this study, amine-functionalized polystyrene (PS) latex nanoparticles were synthesized through emulsifier-free emulsion polymerization and utilized as nanosorbents for PBTC detection via a straightforward latex agglutination method. This phenomenon is facilitated by electrostatic and hydrogen bonding interactions between the positively charged layers on the particle’s surface and the negatively charged PBTC molecules. The pH and concentration of the PBTC solution are key factors influencing the adsorption behavior and capacity of the functionalized latex particles. A graphical representation of aggregation domains, dependent on both PBTC concentration and pH, was created. This map serves as an effective tool for detecting PBTC concentration. The resulting particles show great promise for monitoring the concentration range of phosphate additives in water, offering a simple, rapid detection process with low costs and reduced chemical and equipment requirements.

A Multisystemic Approach Revealed Aminated Polystyrene Nanoparticles-Induced Neurotoxicity.

Exposure to plastic nanoparticles has dramatically increased in the last 50 years, and there is evidence that plastic nanoparticles can be absorbed by organisms and cross the blood-brain-barrier (BBB). However, their toxic effects, especially on the nervous system, have not yet been extensively investigated, and most of the knowledge is based on studies using different conditions and systems, thus hard to compare. In this work, physicochemical properties of non-modified polystyrene (PS) and amine-functionalized PS (PS-NH2 ) nanoparticles are initially characterized. Advantage of a multisystemic approach is then taken to compare plastic nanoparticles effects in vitro, through cytotoxic readouts in mammalian cell culture, and in vivo, through behavioral readouts in the nematode Caenorhabditis elegans (C. elegans), a powerful 3R-complying model organism for toxicology studies. In vitro experiments in neuroblastoma cells indicate a specific cytotoxic effect of PS-NH2 particles, including a decreased neuronal differentiation and an increased Amyloid β (Aβ) secretion, a sensitive readout correlating with Alzheimer's disease pathology. In parallel, only in vivo treatments with PS-NH2 particles affect C. elegans development, decrease lifespan, and reveal higher sensitivity of animals expressing human Aβ compared to wild-type animals. In summary, the multisystemic approach discloses a neurotoxic effect induced by aminated polystyrene nanoparticles.

Unraveling the in vivo fate of inhaled micro- and nanoplastics with PET imaging

Microplastics and nanoplastics have become ubiquitous environmental pollutants. The threat these plastics pose to human health has fueled research focused on their pathophysiology and toxicology, yet many of their fundamental properties — for example, their in vivo pharmacokinetics — remain poorly understood. In this investigation, we have harnessed positron emission tomography (PET) to track the in vivo fate of micro- and nanoplastics administered to mice intratracheally and intravenously. To this end, 1 μm and 20 nm diameter amine-functionalized polystyrene particles were modified with an isothiocyanate-bearing variant of desferrioxamine (DFO) and radiolabeled with the positron-emitting radiometal [89Zr]Zr4+. Both radioplastics — [89Zr]Zr-DFO-PS1000 and [89Zr]Zr-DFO-PS20 — were produced in ∼95% radiochemical yield and found to be >85% stable to demetallation over one week at 37 °C in human serum and simulated lung fluid. The incubation of [89Zr]Zr-DFO-PS1000 and [89Zr]Zr-DFO-PS20 with MH-S cells revealed that the majority of the former were phagocytosed by alveolar macrophages within 4 h, while the latter largely evaded consumption. Finally, the in vivo behavior of the radioplastics was interrogated in mice upon intravenous and intratracheal administration. PET imaging and biodistribution experiments revealed that the intravenously injected plastics accumulated primarily in the liver and spleen, yielding hepatic radioactivity concentrations of 101 ± 48 %ID/g and 92 ± 22 %ID/g at 168 h post-injection for [89Zr]Zr-DFO-PS1000 and [89Zr]Zr-DFO-PS20, respectively. In contrast, the mice that received the radioplastics via intratracheal installation displayed the highest uptake in the lungs at the end of one week: 4 ± 2 %ID/g for [89Zr]Zr-DFO-PS1000 and 32 ± 6 %ID/g for [89Zr]Zr-DFO-PS20. Ultimately, this work illustrates the critical role that the route of exposure plays in the bioaccumulation of plastic particles, reveals that size dramatically influences the pulmonary retention of inhaled particles, and underscores the value of PET imaging as a tool for studying the pharmacokinetics of environmental pollutants.

Porphyrin-Modified Beads for Use as Compensation Controls in Flow Cytometry

Flow cytometry can rapidly characterize and quantify diverse cell populations based on fluorescence measurements. The cells are first stained with one or more fluorescent reagents, each functionalized with a different fluorescent molecule (fluorophore) that binds to cells selectively based on their phenotypic characteristics, such as cell surface antigen expression. The intensity of fluorescence from each reagent bound to cells can be measured on the flow cytometer using channels that detect a specified range of wavelengths. When multiple fluorophores are used, the light from individual fluorophores often spills over into undesired detection channels, which requires a correction to the fluorescence intensity data in a process called compensation. Compensation control particles, typically polymer beads bound to a single fluorophore, are needed for each fluorophore used in a cell labeling experiment. Data from compensation particles from the flow cytometer are used to apply a correction to the fluorescence intensity measurements. This protocol describes the preparation and purification of polystyrene compensation beads covalently functionalized with the fluorescent reagent meso-tetra(4-carboxyphenyl) porphine (TCPP) and their application in flow cytometry compensation. In this work, amine-functionalized polystyrene beads were treated with TCPP and the amide coupling reagent EDC (N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride) at pH 6 and at room temperature for 16 h with agitation. The TCPP beads were isolated by centrifugation and resuspended in a pH 7 buffer for storage. TCPP-related particulates were observed as a byproduct. The number of these particulates could be reduced using an optional filtration protocol. The resultant TCPP beads were successfully used on a flow cytometer for compensation in experiments with human sputum cells labeled with multiple fluorophores. The TCPP beads proved stable following storage in a refrigerator for 300 days.

Effect of polystyrene nanoplastics and their degraded forms on stem cell fate

Several studies have examined the effects of micro- and nanoplastics on microbes, cells, and the environment. However, only a few studies have examined their effects—especially, those of their reduced cohesiveness—on cell viability and physiology. We synthesized surfactant-free amine-functionalized polystyrene (PS) nanoparticles (NPs) and PS-NPs with decreased crosslinking density (DPS-NPs) without changing other factors, such as size, shape, and zeta potential and examined their effects on cell viability and physiology. PS- and DPS-NPs exhibited reactive oxygen species (ROS) scavenging activity by upregulating GPX3 expression and downregulating HSP70 (ROS-related gene) and XBP1 (endoplasmic reticulum stress-related gene) expression in human bone marrow-derived mesenchymal stem cells (hBM-MSCs). Additionally, they led to upregulation of MFN2 (mitochondrial fusion related gene) expression and downregulation of FIS1 (mitochondrial fission related gene) expression, indicating enhanced mitochondrial fusion in hBM-MSCs. Cell-cycle analysis revealed that PS- and DPS-NPs increased the proportion of cells in the S phase, indicating that they promoted cell proliferation and, specifically, the adipogenic differentiation of hBM-MSCs. However, the cytotoxicity of DPS-NPs against hBM-MSCs was higher than that of PS-NPs after long-term treatment under adipogenic conditions.

Facile and Safe Synthesis of Novel Self-Pored Amine-Functionalized Polystyrene with Nanoscale Bicontinuous Morphology.

The chloromethyl-functionalized polystyrene is the most commonly used ammonium cation precursor for making anion exchange resins (AER) and membranes (AEM). However, the chloromethylation of polystyrene or styrene involves highly toxic and carcinogenic raw materials (e.g., chloromethyl ether) and the resultant ammonium cation structural motif is not stable enough in alkaline media. Herein, we present a novel self-pored amine-functionalized polystyrene, which may provide a safe, convenient, and green process to make polystyrene-based AER and AEM. It is realized by hydrolysis of the copolymer obtained via random copolymerization of N-vinylformamide (NVF) with styrene (St). The composition and structure of the NVF-St copolymer could be controlled by monomeric ratio, and the copolymers with high NVF content could form bicontinuous morphology at sub-100 nm levels. Such bicontinuous morphology allows the copolymers to be swollen in water and self-pored by freeze-drying, yielding a large specific surface area. Thus, the copolymer exhibits high adsorption capacity (226 mg/g for bisphenol A). Further, the amine-functionalized polystyrene has all-carbon backbone and hydrophilic/hydrophobic microphase separation morphology. It can be quaternized to produce ammonium cations and would be an excellent precursor for making AEM and AER with good alkaline stability and smooth ion transport channels. Therefore, the present strategy may open a new pathway to develop porous alkaline stable AER and AEM without using metal catalysts, organic pore-forming agents, and carcinogenic raw materials.

In Vitro Determination of the Immunogenic Impact of Nanomaterials on Primary Peripheral Blood Mononuclear Cells.

Investigation of the potential for nanomaterials to generate immunogenic effects is a key aspect of a robust preclinical evaluation. In combination with physicochemical characterization, such assessments also provide context for how material attributes influence biological outcomes. Furthermore, appropriate models for these assessments allow accurate in vitro to in vivo extrapolation, which is vital for the mechanistic understanding of nanomaterial action. Here we have assessed the immunogenic impact of a small panel of commercially available and in-house prepared nanomaterials on primary human peripheral blood mononuclear cells (PBMCs). A diethylaminoethyl-dextran (DEAE-dex) functionalized superparamagnetic iron oxide nanoparticle (SPION) generated detectable quantities of tumor necrosis factor α (TNFα), interleukin-1β (IL-1β), and IL-10, the only tested material to do so. The human leukemia monocytic cell line THP-1 was used to assess the potential for the nanomaterial panel to affect cellular oxidation-reduction (REDOX) via measurement of reactive oxygen species and reduced glutathione. Negatively charged sulfonate-functionalized polystyrene nanoparticles demonstrated a size-related trend for the inhibition of caspase-1, which was not observed for amine-functionalized polystyrene of similar sizes. Silica nanoparticles (310 nm) resulted in a 93% increase in proliferation compared to the untreated control (p < 0.01). No other nanomaterial treatments resulted in significant change from that of unstimulated PBMCs. Responses to the nanomaterials in the assays described demonstrate the utility of primary cells as ex vivo models for nanomaterial biological impact.

Photodynamic antimicrobial chemotherapy of a dimethylamino-functionalized asymmetric zinc(II) phthalocyanine and its quaternized derivative against Staphylococcus aureus when supported on asymmetric polystyrene polymer membranes

Membrane applications are hindered by fouling. Photoactive membranes (containing photosensitizers) show photodynamic antimicrobial chemotherapy (PACT) activity which reduces biological fouling. In this work we use phthalocyanines (Pcs) as photosensitizers. The Pcs used are: 2-(4-carboxyphenoxy)-9(10), 16(17), 23(24)-tris(dimethylamino) phthalocyaninato zinc(II) (1) and the quaternized 2-(4-carboxyphenoxy)-9(10), 16(17), 23(24)-tris(trimethylamino) phthalocyanine zinc(II) methyl sulfate (2). Complex 2 showed an enhanced singlet oxygen quantum yield (ΦΔ) of 0.76 compared to 0.53 for 1. Complex 2 showed enhanced PACT activity against Staphylococcus aureus giving a log reduction value of 9.4, while its precursor (complex 1) gave 0.08. The complexes were then conjugated to amine-functionalized polystyrene and embedded into polystyrene to form membranes resulting in ΦΔ values of 0.24 and 0.27 for complexes 1 and 2 respectively in water. The latter membrane showed better PACT activity.

In Situ Measurement of the Size Distribution and Concentration of Insulating Particles by Electrochemical Collision on Hemispherical Ultramicroelectrodes.

One of the greatest limitations in electrochemical collision/nanoimpact methods is the inability to quantify the size of colliding species due to the uneven current distribution on a disk ultramicroelectrode UME (so-called edge effect). This phenomenon arises since radial diffusion is greater at the edge than the center of the active electrode surface. One method of solving this problem is fabrication of a hemispherical UME. We describe the fabrication of a hemispherical Hg UME on a disk UME by a solution-based electrochemical method, chronocoulometry. The use of hemispherical Hg UME to detect collisions of individual amine-functionalized polystyrene beads removes the "edge effect" and enables simultaneous measurements of the concentration and the size distribution of colloids in suspension. Using finite element simulations, we deduce a quantitative relation between the distribution of current step size and the size distribution of the bead. The frequency of collision measured for a given size of bead is then converted into a concentration (in mol/L) by a quantification of the relative contributions of migration and diffusion for each size of bead. Under our experimental conditions (low concentration of supporting electrolyte), migration dominates the flux of bead. The average size of polystyrene beads of 0.5 and 1 μm radius obtained by electrochemistry and scanning electron microscopy (SEM) differs by only -8% and -9%, respectively. The total concentration of polystyrene beads of 0.5 and 1 μm radius obtained by electrochemistry is found in close agreement (<10% of error) with their nominal concentrations (25 and 100 fM).

Effect of Amine Surface Density on CO2 Adsorption Behaviors of Amine-Functionalized Polystyrene

Abstract Ethylenediamine was grafted onto a polystyrene surface to study the relationship between amine density and amine efficiency. Amine-tethered polystyrene was synthesized in two steps: (1) chloromethylation and (2) amination. The products were characterized by argentometry, N2 physisorption, thermogravimetric analysis, X-ray diffraction, and FT-IR spectroscopy. The amine efficiency declined drastically when the amine density was less than 1 amine molecule per nm2, because formation of ammonium carbamate is difficult under such conditions. A double-functionalization method was introduced to improve the CO2 uptake and amine efficiency of the amine-grafted sorbent by impregnating more amino groups into the porous structure. The combination of grafted and mobile amino groups led to a synergic effect, resulting in a CO2 uptake of up to 20.2 wt % at 30 °C and 1 bar CO2. It was concluded that double-functionalization with tetraethylenepentamine was advantageous for enhancing the amine efficiency, whereas double-functionalization with polyethyleneimine was advantageous for enhancing the cyclic stability of the sorbent.

Pulse Chromatographic Studies of Adsorption of CO2, CH4, and N2 Using Amine Functionalized Polystyrene Adsorbents

Adsorption of CO2, CH4, and N2 was investigated using pulse concentration chromatography on polystyrene functionalized by covalently attached diethanolamine, dimethylamine, imidazole, and N-methyl piperazine. The adsorption equilibrium constants at different temperatures were estimated by fitting the experimental chromatograms into a non-linear equilibrium dispersive chromatography model using gPROMS. Axial dispersion was found to be the controlling mechanism for dispersion of the chromatograms. The heat of adsorption and corresponding equilibrium selectivities were determined from the adsorption equilibrium constants. The imidazole based adsorbent showed the highest affinity for CO2.

Equilibrium Adsorption Studies of CO2, CH4, and N2 on Amine Functionalized Polystyrene

Adsorption of CO2, CH4, and N2 has been investigated using amine functionalized polymeric resins having diethanolamine, imidazole, dimethylamine, and N-methyl piperazine covalently attached to the styrene-divinyl benzene copolymer (PS) matrix. The equilibrium adsorption of CO2, CH4, and N2 was examined on these functionalized polymers at pressures from atmospheric to 40 atm for CO2 and N2 while up to 10 atm for CH4 at 303 K. PS-Imidazole showed the highest adsorption capacity for CO2 as compared to other functionalized polymers. No significant uptake of CH4 and N2 was observed at low pressures by any of the functionalized polymers. The adsorption isotherms were analyzed using dual mode sorption model and Ideal Adsorbed Solution Theory (IAST).

Preparation of polypropylene and polystyrene with NCO and NH2 functional groups and their applications in polypropylene/polystyrene blends

Isocyanate- and amine-functionalized polypropylene (PP) and polystyrene (PS) were prepared through grafting and copolymerization method. These compounds are used as precursors for PP-graft-PS (PP-g-PS) copolymers and reacted at the matrix interface of PP/PS blends. Functionalized polymer structures were characterized by 1H NMR and FTIR spectroscopy. The effects of the synthesized compatibilizer on the rheological and morphological behavior of PP/PS blends were investigated systematically. Results showed that the functional polymer was successfully synthesized, and the additional two different compatibilizer systems dramatically decreased the size of the dispersed phase domains in PP/PS blends. Compared with the uncompatibilized blends, compatibilized blends exhibited a slightly higher crystallization temperature because the melting points of the blend components were not evidently affected by the addition of compatibilizer, as revealed by differential scanning calorimetry. The compatibilizer effect on the PP/PS blends was reflected through rheological property and dynamic mechanical analysis. POLYM. ENG. SCI., 55:614–623, 2015. © 2014 Society of Plastics Engineers

Enhancement of thermal stability, processability and morphology of polystyrene blends

To improve the thermal and morphological profiles of polystyrene (PS), we probed the effect of functionalized PS on reactive compatibilization with polyethylene-graft-maleic anhydride (PE-g-MA). In this regard a three pronged strategy was pursued i.e. modification of PS to amine functionalized polystyrene (APS), followed by the blend films fabrication through in situ reactive compatibilization. Finally spectral, thermal, mechanical and morphological techniques were employed for the characterization of ensued blend films. The properties of binary blends were analyzed as a function of PS and APS content. Two blend systems; PS/PE-g-MA and APS/PE-g-MA, were prepared and investigated over a range (0–100wt.%) of pristine PS and modified APS ratios. Reactively compatibilized systems demonstrated enhanced thermal stability, processability, morphology and interfacial adhesion by virtue of in situ formed APS/PE-g-MA copolymer that was confirmed using FTIR spectroscopy. Optimum thermal and morphological properties were shown by 90/10 APS/PE-g-MA blend. Potential applications and future prospects are envisaged.

Comparison of two in vitro systems to assess cellular effects of nanoparticles-containing aerosols

Inhalation treatment with nanoparticle containing aerosols appears a promising new therapeutic option but new formulations have to be assessed for efficacy and toxicity. We evaluated the utility of a VITROCELL®6 PT-CF+PARI LC SPRINT® Baby Nebulizer (PARI BOY) system compared with a conventional MicroSprayer. A549 cells were cultured in the air–liquid interface, exposed to nanoparticle aerosols and characterized by measurement of transepithelial electrical resistance and staining for tight junction proteins. Deposition and distribution rates of polystyrene particles and of carbon nanotubes on the cells were assessed. In addition, cytotoxicity of aerosols containing polystyrene particles was compared with cytotoxicity of polystyrene particles in suspension tested in submersed cultures. Exposure by itself in both exposure systems did not damage the cells. Deposition rates of aerosolized polystyrene particles were about 700 times and that of carbon nanotubes about 4 times higher in the MicroSprayer than in the VITROCELL®6 PT-CF system. Cytotoxicity of amine-functionalized polystyrene nanoparticles was significantly higher when applied as an aerosol on cell cultured in air–liquid interface culture compared with nanoparticle suspensions tested in submersed culture. The higher cytotoxicity of aerosolized nanoparticles underscores the importance of relevant exposure systems.

Synthesis and Characterization of Amine-Functionalized Polystyrene Nanoparticles

Functionalized polymer nanoparticles have been synthesized through an intramolecular cross-linking reaction with polystyrene as the backbone and an amino group as the functional moiety. The intramolecular cross-linking reaction was performed under ultradilute conditions, and the cross-linked polymers were characterized by gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), and atomic force microscopy (AFM). The availability of the amino moiety in the nanoparticle for further functionalization was confirmed by its reaction with trimethylacetyl chloride.

Synthesis of end- and mid-Phthalic Anhydride Functional Polymers by Atom Transfer Radical Polymerization

Polystyrene (PS) and poly(methyl methacrylate) (PMMA) having a single di-tert-butyl phthalate (DTBP) group either at the chain end or in the middle of the chain were synthesized by Cu(I) ion mediated atom transfer radical polymerization (ATRP). The di-tert-butyl phthalate initiators 7 and 8 (for end-functional polymers) and 11 (for mid-functional polymers) were prepared from commercially available di-tert-butyl acetylene dicarboxylate (1) and myrcene (2) in four and six steps, respectively, with high overall yields. The DTBP functionalized polymers could be cleanly converted to the corresponding phthalic anhydride (PA) functional polymers by pyrolysis. The pyrolysis process could be easily monitored using conventional 1H NMR spectroscopy, by observing the significant chemical shift change of the alkyl linker existing in the initiators. Kinetic study of the pyrolysis revealed that the mechanism of the DTBP group pyrolysis to phthalic anhydride (PA) group follows two first-order consecutive reactions having a phthalic diacid (DA) as an observable intermediate. When the PA-functionalized PMMA was subjected to reactive blending at 180 °C with an amine-functionalized PS, the conversion reached a maximum (>90%) in less than 2 min, which is considerably faster than the corresponding reaction of an aliphatic anhydride (e.g., succinic anhydride)-functionalized PMMA. A competition experiment with small molecules showed that phthalic anhydride reacts 5 times faster than succinic anhydride with PS-NH2.