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Methods in Molecular Biology (Clifton,... 2012A method for the preparation of carbohydrate microarrays inside 96-well polystyrene microtiter plates is described. The key step in this strategy represents the...
A method for the preparation of carbohydrate microarrays inside 96-well polystyrene microtiter plates is described. The key step in this strategy represents the synthesis of carbohydrate-dextran conjugates by copper (I)-catalyzed [3 + 2] cycloaddition between alkyne carbohydrate derivative and a specially designed azido dextran polymer. The conjugates adsorb efficiently on polystyrene surface and can be printed inside 96-well plates using a non-contact piezoelectric microarrayer. Model interactions with a selection of lectins (concanavalin A, wheat germ agglutinin, Erythrina Cristagalli) display the efficiency of the immobilization method, its reproducibility and the specificity of biomolecular interactions occurring at the polystyrene-water interface.
Topics: Carbohydrates; Dextrans; Microarray Analysis; Polystyrenes
PubMed: 22057538
DOI: 10.1007/978-1-61779-373-8_25 -
ACS Macro Letters Aug 2022Dry polymer brushes have attracted great attention because of their potential utility in regulating interface properties. However, it is still unknown whether dry...
Dry polymer brushes have attracted great attention because of their potential utility in regulating interface properties. However, it is still unknown whether dry polymer brushes will exhibit degrafting behavior as a result of thermal annealing. Herein, a study of the conformational entropy effect on thermal degrafting of dry polystyrene (PS) brushes is presented. For PS brushes with an initial grafting density (σ) of 0.61 nm, degrafting behavior was observed at 393 K, and the equilibrium σ was approximately 0.14 nm at 413 K. However, for brushes with σ ≤ 0.14 nm, thermal degrafting was not observed even if the temperature was increased to 453 K. Furthermore, we found that the degrafting rate was faster for PS brushes with higher σ and higher molecular weights when σ > 0.14 nm. Our findings confirmed that degrafting is a mechanochemical activation process driven by tension imposed on bonds that anchor the chains to the surface, and the process is amplified by conformational entropy.
Topics: Entropy; Molecular Conformation; Polymers; Polystyrenes; Surface Properties
PubMed: 35920565
DOI: 10.1021/acsmacrolett.2c00263 -
Critical Reviews in Toxicology Jul 2018Oligomers of styrene have been identified in polystyrene (PS) polymer samples intended for food packaging. Such oligomers contribute to nonintentionally added substances... (Review)
Review
Oligomers of styrene have been identified in polystyrene (PS) polymer samples intended for food packaging. Such oligomers contribute to nonintentionally added substances (NIAS) that may migrate into food or food simulants and therefore have to be assessed for the potential risk to health. No oligomers larger than dimers and trimers of styrene have been found to be present in PS. Some in vivo and in vitro information indicative of an endocrine activity for some specific oligomers suggest concerns for their potential for endocrine disruption in humans. Data on endocrine activity available from in vitro and in vivo screening approaches and from non-guideline studies in experimental animals were evaluated. The different test methods were classified according to the OECD Conceptual Framework for Testing and Assessment of Endocrine Disruptors (OECD) and the ranking system of Borgert et al. proposed in 2014. The quality and reliability of each study is further assessed by professional judgment. The integration of the total information supports the conclusion that neither specific oligomers, nor their mixtures, potentially migrating into food are endocrine disruptors according to the definition of EFSA and WHO/IPCS.
Topics: Animals; Endocrine Disruptors; Endocrine Glands; Female; Food Packaging; Humans; Male; Polystyrenes; Reproducibility of Results
PubMed: 29648919
DOI: 10.1080/10408444.2018.1447547 -
Environment International Jun 2022The presence and potential toxicity of nanoplastics (NPs) in aquatic ecosystems is an issue of growing concern. Although many studies have investigated the adverse...
The presence and potential toxicity of nanoplastics (NPs) in aquatic ecosystems is an issue of growing concern. Although many studies have investigated the adverse effects of short-term exposure to high concentrations of NPs to aquatic organisms, the information on the consequences caused by the administration of low NPs concentrations over long-term exposure is limited. The present study aimed at investigating the effects induced by a long-term exposure (21-days) to two sub-lethal concentrations of polystyrene nanoplastics (PS-NPs; 0.05 and 0.5 µg/mL) on Daphnia magna. A multi-level approach was performed to assess potential sub-individual (i.e., molecular and biochemical) and individual (i.e., behavioural) adverse effects. At molecular level, the modulation of the expression of genes involved in antioxidant defence, response to stressful conditions and specific physiological pathways was investigated. Oxidative stress (i.e., the amount of pro-oxidants, the activity of antioxidant and detoxifying enzymes and lipid peroxidation) and energetic (i.e., protein, carbohydrate, lipid and total caloric content) biomarkers were applied to assess effects at the biochemical level, while swimming activity was measured to monitor changes in individual behavior. Although the 21-days exposure to PS-NPs induced a slight modulation of gene involved in oxidative stress response, biochemical analyses showed that D. magna individuals did not experience an oxidative stress condition. Significant changes in energy reserves of individuals exposed for 21 days to both the PS-NPs concentrations were observed, but no alterations of swimming activity occurred. Our results highlighted that the exposure to low concentrations of PS-NPs could pose a limited risk to D. magna individuals and suggested the importance of a multi-level approach to assess the risks of NPs on aquatic organisms.
Topics: Animals; Antioxidants; Daphnia; Ecosystem; Microplastics; Polystyrenes; Water Pollutants, Chemical
PubMed: 35489111
DOI: 10.1016/j.envint.2022.107264 -
The Journal of Physical Chemistry. B Oct 2022The effects of temperature, pressure, and imposed strain on the structural transition pathways of glassy atactic polystyrene (aPS) are studied for a wide range of...
The effects of temperature, pressure, and imposed strain on the structural transition pathways of glassy atactic polystyrene (aPS) are studied for a wide range of conditions. By employing an atomistic description of the system, we systematically explore its free energy landscape, emphasizing connections between local free energy minima. A triplet of two minima connected to each other via a first-order saddle point provides the full description of each elementary structural relaxation event. The basis of the analysis is the potential energy landscape (PEL), where efficient methods for finding saddle points and exploring transition pathways have been developed. We then translate the stationary points of the PEL to stationary points of the proper free energy landscape that obeys the macroscopically imposed constraints (either stress- or strain-controlled). By changing the temperature under isobaric conditions (i.e., Gibbs energy landscape), we probe the temperature dependence of the transition rates of the subglass relaxations of aPS, thus obtaining their activation energies by fitting to the Arrhenius equation. The imposition of different strain levels under isothermic conditions allows us to estimate the apparent activation volume of every elementary transition. Our findings are in good agreement with experimental observations for the same system, indicating that both length- and time-scales of the structural transitions of glassy aPS can be obtained by proper free energy minimization of atomistically detailed configurations.
Topics: Polystyrenes; Temperature
PubMed: 36129780
DOI: 10.1021/acs.jpcb.2c04199 -
Environmental Pollution (Barking, Essex... May 2018Microplastics that are released into the environment undergo aging and interact with other substances such as organic contaminants. Understanding the sorption...
Microplastics that are released into the environment undergo aging and interact with other substances such as organic contaminants. Understanding the sorption interactions between aged microplastics and organic contaminants is therefore essential for evaluating the impact of microplastics on the environment. There is little information available on how the aging of microplastics affects their sorption behavior and other properties. We have therefore investigated the effects of an accelerated UV-aging procedure on polystyrene microplastics, which are used in products such as skin cleaners and foams. Physical and chemical particle characterizations showed that aging led to significant surface oxidation and minor localized microcrack formation. Sorption coefficients of organic compounds by polystyrene microplastics following aging were up to one order of magnitude lower than for pristine particles. Sorption isotherms were experimentally determined using a diverse set of probe sorbates covering a variety of substance classes allowing an in-depth evaluation of the poly-parameter linear free-energy relationship (ppLFER) modelling used to investigate the contribution of individual molecular interactions to overall sorption. The ppLFER modelling was validated using internal cross-validation, which confirmed its robustness. This approach therefore yields improved estimates of the interactions between aged polystyrene microplastics and organic contaminants.
Topics: Adsorption; Models, Theoretical; Organic Chemicals; Polystyrenes; Surface Properties; Ultraviolet Rays; Water Pollutants, Chemical
PubMed: 29414343
DOI: 10.1016/j.envpol.2018.01.022 -
Chemico-biological Interactions Sep 2023Nanoplastics are emerging pollutants that pose a potential threat to the environment and organisms and are widely distributed in environmental samples and food chains....
Nanoplastics are emerging pollutants that pose a potential threat to the environment and organisms and are widely distributed in environmental samples and food chains. The accumulation of polystyrene nanoplastics (PS-NPs) in an organism can cause oxidative stress. Currently, toxicity studies of PS-NPs mainly focus on the individual and cellular levels, whereas few studies have been conducted on the molecular mechanisms of the interaction between PS-NPs and catalase (CAT). Based on this, CAT was chosen as the target receptor for molecular toxicity research to reveal the interaction mechanism at the molecular level between PS-NPs and CAT by using various spectroscopic means and enzyme activity detection methods. The results indicated that PS-NPs destroyed the secondary structure of CAT, causing its protein skeleton to loosen and unfold, increasing the content of α-helices, decreasing the content of β-sheets, and exposing the position of the heme group. After exposure to PS-NPs, the internal fluorophore of CAT underwent fluorescence sensitization, resulting in a micelle-like structure, which enhanced the hydrophobicity of aromatic amino acids but did not change their polarity. In addition, the aggregation state of CAT was altered upon binding to PS-NPs, and the volume was further increased. Finally, these structural changes led to a gradual decrease in CAT activity. This study presents a comprehensive assessment of the toxicity of PS-NPs at the molecular level, which can provide more experimental support for the study of the biotoxicological efficacy of PS-NPs.
Topics: Polystyrenes; Microplastics; Catalase; Oxidative Stress; Nanoparticles; Water Pollutants, Chemical
PubMed: 37495201
DOI: 10.1016/j.cbi.2023.110648 -
Soins; La Revue de Reference Infirmiere Dec 1984
Topics: Humans; Hyperkalemia; Polystyrenes
PubMed: 6570569
DOI: No ID Found -
Physical Chemistry Chemical Physics :... Feb 2008Polystyrene nanoparticles were synthesized by emulsion polymerization of styrene. They were functionalized using the conventional surfactant...
Polystyrene nanoparticles in the presence of (ethylene oxide)13(propylene oxide)30(ethylene oxide)13, N,N-dimethyloctylamine-N-oxide and their mixtures. A calorimetric and dynamic light scattering study.
Polystyrene nanoparticles were synthesized by emulsion polymerization of styrene. They were functionalized using the conventional surfactant N,N-dimethyloctylamine-N-oxide (ODAO), the tri-block copolymer (ethylene oxide)(13)(propylene oxide)(30)(ethylene oxide)(13) (L64) and their mixtures. To this purpose, dynamic light scattering and calorimetric experiments were carried out and provided information consistent to each other. The L64 adsorption is Langmuir-type in the copolymer dilute regime and generates complex structures at larger concentrations. In the region where ODAO is in the unimeric state, the adsorption process is cooperative leading to hemi-micelle formation at the polystyrene nanoparticle/water interface. In the concentrated region (above the critical micellar concentration), ODAO forms micelles which interact with the solid substrate most likely through ion-dipole forces. The ODAO addition to the dispersion containing polystyrene particles already wrapped by L64 creates an ODAO thickness around the dispersed particles the size of which is equal to that in the absence of the copolymer, but is built at much lower concentrations. A plausible interpretation of this behavior is that the adsorbed L64 confers to the nanoparticles surface novel properties which enhance the attractive forces with the ODAO molecules.
Topics: Adsorption; Calorimetry; Ethylene Oxide; Light; Nanoparticles; Octanes; Oxides; Polystyrenes; Scattering, Radiation; Solutions; Styrene; Surface Properties; Water
PubMed: 18231681
DOI: 10.1039/b708573g -
Macromolecular Bioscience Dec 2023Particle-mediated self-assembly, such as nanocomposites, microstructure formation in materials, and core-shell coating of biological particles, offers precise control...
Particle-mediated self-assembly, such as nanocomposites, microstructure formation in materials, and core-shell coating of biological particles, offers precise control over the properties of biological materials for applications in drug delivery, tissue engineering, and biosensing. The assembly of similar-sized calcium alginate (CAG) and polystyrene sub-micron particles is studied in an aqueous sodium nitrate solution as a model for particle-mediated self-assembly of biological and synthetic mixed particle species. The objective is to reinforce biological matrices by incorporating synthetic particles to form hybrid particulate networks with tailored properties. By varying the ionic strength of the suspension, the authors alter the energy barriers for particle attachment to each other and to a glass substrate that result from colloidal surface forces. The particles do not show monotonic adsorption trend to glass with ionic strength. Hence, apart from DLVO theory-van der Waals and electrostatic interactions-the authors further consider solvation and bridging interactions in the analysis of the particulate adsorption-coagulation system. CAG particles, which support lower energy barriers to attachment relative to their counterpart polystyrene particles, accumulate as dense aggregates on the glass substrate. Polystyrene particles adsorb simultaneously as detached particles. At high electrolyte concentrations, where electrostatic repulsion is largely screened, the mixture of particles covers most of the glass substrate; the CAG particles form a continuous network throughout the glass substrate with pockets of polystyrene particles. The particulate structure is correlated with the adjustable energy barriers for particle attachment in the suspension.
Topics: Polystyrenes; Alginates; Colloids; Adsorption; Osmolar Concentration; Particle Size
PubMed: 37551162
DOI: 10.1002/mabi.202300219