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PubMed1984

Uptake of carbon and polystyrene particles by the sinusoidal endothelium of rabbit bone marrow and liver and rat bone marrow, with special reference to multiparticle-pinocytosis.

The endocytosis of tracer particles by sinusoidal endothelial cells was studied in the bone marrow and liver of the rabbit and in the bone marrow of the rat after intravenous injection. The tracer particles used included carbon particles and polystyrene particles of different sizes ranging from 0.11 to 5.7 micron in diameter. The sinusoidal endothelial cells of the rabbit liver and rat bone marrow took up carbon through the formation of bristle-coated vesicles at the luminal surface, but they eventually failed to ingest polystyrene particles of 0.11 micron or larger. On the other hand, the sinusoidal endothelial cells of the rabbit bone marrow took up carbon and polystyrene particles varying from 0.11 to 2.02 micron in diameter. These endothelial cells were found to sequester circulating tracer particles in the cytoplasm through the formation of two kinds of vesicles at the luminal surface: bristle-coated vesicles and "multiparticle-pinocytotic vesicles." This special type of pinocytotic vesicle was larger in diameter than the bristle-coated vesicle and variable in size according to the size or amount of the particles to be sequestered. Carbon and 0.11 micron polystyrene particles were taken up by means of both the bristle-coated vesicles and multiparticle-pinocytotic vesicles, whereas particles 0.30 micron in diameter or larger were taken up by the vesicles similar in nature to multiparticle-pinocytotic vesicles. A sequence for the morphological events occurring in the formation of multiparticle-pinocytotic vesicles in the sinusoidal endothelial cells of rabbit bone marrow shall be suggested and discussed.

Animals↗

PubMed1995

Factors affecting the oral uptake and translocation of polystyrene nanoparticles: histological and analytical evidence.

Quantitative and qualitative evidence from our laboratories on the absorption and translocation of polystyrene latex nanoparticles both by histological (qualitative) and analytical measurement of levels of polystyrene (quantitative) is briefly reviewed in this paper. We have previously compared the uptake of nonionized polystyrene latex ranging in size from 50nm to 3 microns, and made some comparisons of uptake between carboxylated microspheres and nonionic systems, showing the lower uptake of the former through the lymphoid tissue of the gastrointestinal tract. Size is a key parameter, uptake increasing with decreasing particle diameter. Early evidence suggested that uptake is by way of the Peyer's patches and other elements of the gut associated lymphoid tissue (GALT). Adsorption of hydrophilic block-copolymers onto polystyrene markedly reduces the uptake by intestinal GALT. Modification of the surface with specific ligands such as by covalent attachment of tomato lectin molecules has indicated widespread uptake by non-GALT tissues, following their binding to and internalisation by enterocytes. The ability to decrease and increase uptake is clear evidence of a phenomenon which has the potential for further control to allow it to be exploited fully for drug or vaccine delivery. The evidence to date with nanoparticles as carriers systems for labile drugs such as proteins by the oral route remains to be substantiated.

Animals↗

PubMed2000

Immobilization of antibodies on ultraflat polystyrene surfaces.

BACKGROUND: Functional antibody surfaces were prepared on ultraflat polystyrene surfaces by physical adsorption, and the uniform distribution of monoclonal antibodies against hepatitis B surface antigen (anti-HBs) on such surfaces and the presence of dense hepatitis B surface antigen (HBsAg) particles captured by immobilized antibodies were identified. METHODS: A model polystyrene film was spin-coated directly onto a silicon wafer surface. Atomic force microscopy was used to directly monitor the immobilization of anti-HBs antibodies and their specific molecular interaction with HBsAg. Enzyme immunoassay was also used to characterize functional antibody surfaces. RESULTS: A mean roughness of 2 A for areas of 25 microm(2) was produced. We found a uniform distribution of anti-HBs antibodies on ultraflat polystyrene surfaces and the presence of dense HBsAg particles bound to such anti-HBs surfaces after incubation with HBsAg. CONCLUSIONS: This study confirmed the potential of preparing dense, homogeneous, highly specific, and highly stable antibody surfaces by immobilizing antibodies on polystyrene surfaces with controlled roughness. It is expected that such biofunctional surfaces could be of interest for the development of new solid-phase immunoassay techniques and biosensor techniques.

Adsorption↗

PubMed1978

Superoxide production from human polymorphonuclear leucocytes stimulated with immunoglobulins of different classes and fragments of IgG bound to polystyrene dishes.

Polystyrene surfaces coated with proteins at alkaline pH were found to be useful to investigate the stimulation of neutrophils independently of phagocytosis. Human neutrophils, when exposed to appropriate stimuli, release superoxide anion (O2-). We have measured superoxide dismutase-inhibitable cytochrome c reduction by cells stimulated with various kinds of protein coated on polystyrene dishes. Native immunoglobulins in solution did not stimulate O2- generation in neutrophils. IgG and IgA adherent to polystyrene dishes stimulated O2- generation in neutrophils, but IgM, IgD, IgE, albumin, Fab, and Fc of IgG on polystyrene dishes did not.

Humans↗

PubMed1981

In vitro stimulation of alveolar macrophage metabolic activity by polystyrene in the absence of phagocytosis.

The technique of lucigenin-dependent phagocytic chemiluminescence was used to investigate the stimulation of metabolic activity in human alveolar macrophages on contact with polystyrene. The results were similar to those obtained using a spectrophotometric assay of superoxide release based on ferricytochrome C reduction. There was a marked stimulation of metabolic activity in the alveolar macrophages on incubation at 37 degrees in polystyrene vials which was shown to be due to contact with and adherence to the polystyrene. This could be reduced by the addition of gelatin or foetal calf serum without preventing the ability of the cells to respond to opsonized particles. By using several metabolic inhibitors it was shown that lucigenin-dependent chemiluminescence was associated with the release of superoxide at the time of adherence. The implications of these findings are discussed and it is suggested that the stimulation of alveolar macrophage metabolic activity by contact with polystyrene can contribute to the observed difference between alveolar macrophage and polymorphonuclear leucocyte oxygen consumption in the absence of phagocytosis.

Antimetabolites↗

PubMed2006

Influence of physicochemical properties of laser-modified polystyrene on bovine serum albumin adsorption and rat C6 glioma cell behavior.

Biomaterial surface modification is an efficient way of improving cell-material interactions. In this study, sub-micrometer laser-induced periodic surface structures (LIPSS) were produced on polystyrene by laser irradiation. FT-IR analysis confirmed that this treatment also led to surface oxidation and anisotropic orientation of the produced carbonyl groups. As a consequence, the surface energy of the laser-treated polystyrene was 1.45 times that of the untreated polystyrene, as measured by contact-angle goniometry. Protein adsorption and rat C6 glioma cell behavior on the two substrates were investigated, showing that the changed physicochemical properties of laser-modified polystyrene surface led to an increase in the quantity of adsorbed bovine serum albumin and significantly affected the behavior of rat C6 glioma cells. In the early stages of cell spreading, cells explored their microenvironment using filopodium as the main sensor. Moreover, cells actively aligned themselves along the direction of LIPSS gradually and cell attachment and proliferation were significantly enhanced.

Adsorption↗

PubMed2000

Solution Properties of Star-Shaped Polystyrenes Having Peripheral Charged Ions.

Functionalized polystyrene stars were prepared by copolymerization of polystyryl lithium with divinylbenzene in a mixture of benzene/tetrahydropyran, where the polystyrene arms were prepared by anionic polymerization using [2-[(N,N-dimethylamino)-methyl]phenyl]lithium as the initiator. These functional stars were converted by quaternization with methyl iodide into polystyrene stars having peripheral positive charges. We studied the charge effects on the solution properties of such stars. The hydrodynamic dimension of peripheral charged polystyrene (PS) stars depended strongly on the solubility parameter between PS segments and solvent. Copyright 2000 Academic Press.

Journal Article↗

PubMed2005

Whole range of chain dynamics in entangled polystyrene melts revealed from creep compliance: thermorheological complexity between glassy-relaxation region and rubber-to-fluid region. 1.

The rubber(like)-to-fluid region of the creep compliance J(t) results reported by Plazek of two nearly monodisperse polystyrene melts in the entanglement region have been quantitatively analyzed in terms of the extended reptation theory (ERT), giving the frictional factor K (= zetab2kTpi2m2) in quantitative agreement with the values obtained previously from analyzing the relaxation modulus Gt line shapes as well as calculated from the viscosity and diffusion data-a quantity shown independent of molecular weight as expected from the theory. Using the successful description of Jt in terms of ERT in the rubber(like)-to-fluid region as the reference frame in time, the glassy-relaxation process microG(t) that occurs in the small-compliance short-time region of J(t) can be studied in perspective. As shown from the analysis in terms of a stretched exponential form for microG(t) incorporated into ERT, the temperature dependence of the energetic interactions-derived microG(t) process being stronger in a simple manner than that of the entropy-derived ERT processes accounts fully for the uneven thermorheological complexity occurring in J(t) as initially observed by Plazek. When the results of analysis being displayed in the G(t) form, the relative roles of the energetic interactions-derived dynamic process and the entropy-derived ones in polystyrene are clearly revealed. It is shown that at the calorimetric glass transition temperature (Tg) the contribution from energetic interactions among segments to G(t) at the time scale of the highest Rouse-Mooney normal mode greatly exceeds that derived from entropy, indicating vitrification at the Rouse-segmental level. At the same time the Rouse-Mooney normal modes provide an internal yardstick for estimating the characteristic length scale of a polymer at Tg, giving approximately 3 nm for polystyrene. On the basis of the obtained results, the basic mechanism for the thermorheological complexity occurring in polystyrene is analyzed. It is shown that this basic mechanism should be also responsible for the breakdown of the Stoke-Einstein equation in relating the translational diffusion constant and viscosity as observed in glass-forming liquids, such as OTP and TNB, in approaching Tg from above.

Journal Article↗

PubMed2005

Synthesis of micrometer-sized silica-stabilized polystyrene latex particles.

Micrometer-sized silica-stabilized polystyrene latexes have been readily prepared by alcoholic dispersion polymerization using a 13 or 22 nm commercial alcoholic silica sol as the sole stabilizing agent. These resulting surfactant-free polystyrene particles have relatively narrow particle size distributions and contain surprisingly low levels of silica (</=1.1% by mass), as judged by disk centrifuge photosedimentometry and thermogravimetry, respectively. Transmission electron microscopy studies indicate that the silica sol is located exclusively at the surface of the polystyrene latex particles at submonolayer coverage. The polymerization of styrene in the absence of the silica sol leads to macroscopic precipitation of the polystyrene. Hence, the presence of silica sol is essential for the colloid stability of these latexes, which presumably involves a charge stabilization mechanism.

Letter↗

PubMed2006

Vacuum-ultraviolet photochemically initiated modification of polystyrene surfaces: morphological changes and mechanistic investigations.

Vacuum-ultraviolet (VUV) irradiation (lambda(exc): 172 +/- 12 nm) of polystyrene films in the presence of oxygen produced not only oxidatively functionalized surfaces, but generated also morphological changes. Whereas OH- and C=O-functionalized surfaces might be used for e.g. secondary functionalization, enhanced aggregation or printing, processes leading to morphological changes open new possibilities of microstructurization. Series of experiments made under different experimental conditions brought evidence of two different reaction pathways: introduction of OH- and C=O-groups at the polystyrene pathways is mainly due to the reaction of reactive oxygen species (hydroxyl radicals, atomic oxygen, ozone) produced in the gas phase between the VUV-radiation source and the substrate. However, oxidative fragmentation leading to morphological changes, oxidation products of low molecular weight and eventually to mineralization of the organic substrate is initiated by electronic excitation of the polymer leading to C-C-bond homolysis and to a complex oxidation manifold after trapping of the C-centred radicals by molecular oxygen. The pathways of oxidative functionalization or fragmentation could be differentiated by FTIR-ATR analysis of irradiated polystyrene surfaces before and after washing with acetonitrile and microscopic fluorescence analysis of the surfaces secondarily functionalized with the N,N,N-tridodecyl-triaza-triangulenium (TATA) cation. Ozonization of the polystyrene leads to oxidative functionalization of the polymer surface but cannot initiate the fragmentation of the polymer backbone. Oxidative fragmentation is initiated by electronic excitation of the polymer (contact-mode AFM analysis), and evidence of the generation of intermediate C-centred radicals is given e.g. by experiments in the absence of oxygen leading to cross-linking (solubility effects, optical microscopy, friction-mode AFM) and disproportionation (fluorescence).

Journal Article↗

PubMed1983

Improved Microfouling Assay Employing a DNA-Specific Fluorochrome and Polystyrene as Substratum.

With a direct count assay, 10 fouling bacterial isolates have been characterized for their ability to adhere to glass cover slips and polystyrene dishes. Although most adhered in greater numbers to polystyrene, the preference was statistically significant for only seven isolates at the 95% confidence level, due in part to the greater variability in cell attachment to glass (coefficient of variation, 32.3% for glass compared with 10.0% for polystyrene). Employing polystyrene dishes, a novel microfouling assay was developed, based on the extraction and fluorometric determination of DNA. The assay was rapid, enabled the detection of as little as 0.15 mug of DNA per dish ( approximately 5,000 cells per mm), and showed good agreement with the direct count assay. The DNA method resulted in less variability among three replicates (average coefficient of variation, 7.06%) and allowed for estimation of bacterial density over a larger surface area per sample (1.89 x 10 mm) than was feasible with epifluorescence microscopy (0.06 to 0.1 mm).

Journal Article↗

PubMed1999

Localized, positive charge mediates adhesion of rhodosporidium toruloides to barley leaves and polystyrene

The physicochemical forces that mediate attachment of yeasts to the phylloplane are unknown. Cell surface charge and hydrophobicity and adhesion to polystyrene, glass, and barley were assessed for wild-type Rhodosporidium toruloides and attachment-minus (Att-) mutants. Cells were grown under conditions promoting (excess carbon) or not promoting (excess nitrogen) capsule production. Hydrophobicity was measured by adhesion to xylenes, and surface charge characteristics were assessed by attachment to either DEAE (positive)- or carboxymethyl (CM) (negative)-Sephadex ion-exchange beads. Hydrophobicity and adhesiveness of nonencapsulated, wild-type R. toruloides decreased from mid-log to late stationary phase. Encapsulated wild-type R. toruloides cells were more hydrophobic and more adhesive than nonencapsulated cells. However, two encapsulated Att- mutants were more hydrophobic than the wild type and levels of adhesion of R. toruloides were similar on polystyrene and less hydrophobic glass surfaces. Adhesion of wild-type yeast to barley and polystyrene was correlated with attachment to CM-Sephadex beads, indicating a positive cell surface charge. Sixteen Att- mutants did not exhibit a positive cell surface charge, and wild-type yeast cells that did not attach to CM-Sephadex did not adhere to either polystyrene or barley. Wild-type R. toruloides attached to CM-Sephadex beads by the poles of the cells, indicating a localization of positive charge which was also visualized with India ink. We conclude that localized, positive charge, and not hydrophobic interactions, mediates attachment of R. toruloides to barley leaves.

Journal Article↗

PubMedDate not supplied

Determination of the oestrogenic (uterotrophic) activity of extracts of 'general purpose polystyrene (GPPS)' using immature female rats.

In Japan there is growing concern about the possible adverse effects of consumption of food from styrene containers (mainly those made from polystyrene paper) due to the alleged oestrogenic activity of styrene oligomers (dimers and trimers), which may migrate into the food. To examine the possible oestrogenic activity of styrene dimers and trimers, extracts were made from 'general purpose polystyrene (GPPS)' and administered orally to immature female rats over a 4 day period. Increase of uterus weight (wet and blotted) was used for assessment of possible oestrogenic activity. To establish the sensitivity of the test method, immature rats were treated with diethylstilboestrol (DES), a well-known oestrogenic compound. It was found that treatment of rats with levels of up to 60 microg of styrene dimers and 930 microg of styrene trimers per kilogram body weight per day did not give any statistically significant increase of the uterus weight (wet or blotted), whereas DES caused statistically significant, dose-related increases in uterus weight at levels as low as 0.89 microg kg(-1) body weight day(-1). It was concluded that, compared with the estimated maximum human daily intake of styrene trimers of 1 microg kg(-1) body weight day(-1) from polystyrene food containers, the risk of adverse human health effects with respect to oestrogenicity may be considered negligible.

Administration, Oral↗

PubMed2006

Effect of coating the wells of a polystyrene microtiter plate with xanthorrhizol on the biofilm formation of Streptococcus mutans.

Colonization on the surface of tooth by Streptococcus mutans is an important step in the initiation of dental plaque. Polystyrene microtiter plates have been employed to study bacterial colonization and biofilm formation of periodontal bacteria. The objective of this work was to evaluate the effect of coating the wells of a polystyrene microtiter plate with xanthorrhizol isolated from java turmeric (Curcuma xanthorrhiza Roxb.) on Strep. mutans biofilm formation. Our studies demonstrated that coating of a polystyrene microtiter plate with 5 microg/ml of xanthorrhizol resulted in significant (up to 60%) reduction of adherent cells compared to that of cells in uncoated wells. This result suggests that xanthorrhizol displays potent activity in preventing Strep. mutans biofilm formation.

Animals↗

PubMed1996

Amination of polystyrene microwells: application to the covalent grafting of DNA probes for hybridization assays.

Amine functionalization of polystyrene microwells for covalent binding of DNA is described. Polystyrene support was first carboxylated by permanganate oxidation in diluted sulfuric acid. These functions were activated with water-soluble carbodiimide and grafted with N-methyl-1,3-propane diamine to introduce a free secondary amino group on the support. The samples were characterized by X-ray photoelectron spectroscopy and radiochemical assay. The conditions for covalent linkage of secondary amine on polystyrene microwells were optimized. Functionalized supports were used for covalent binding of a DNA capture probe for the detection of human cytomegalovirus in a sandwich hybridization assay. Sensitivity of the assay compared very well with a commercially available surface, Covalink-NH, microwell plate obtained by electromagnetic irradiation.

Amines↗

PubMed2003

Modeling of the phase equilibria of polystyrene in methylcyclohexane with semi-empirical quantum mechanical methods I.

A method for calculating interaction parameters traditionally used in phase-equilibrium computations in low-molecular systems has been extended for the prediction of solvent activities of aromatic polymer solutions (polystyrene+methylcyclohexane). Using ethylbenzene as a model compound for the repeating unit of the polymer, the intermolecular interaction energies between the solvent molecule and the polymer were simulated. The semiempirical quantum chemical method AM1, and a method for sampling relevant internal orientations for a pair of molecules developed previously were used. Interaction energies are determined for three molecular pairs, the solvent and the model molecule, two solvent molecules and two model molecules, and used to calculated UNIQUAC interaction parameters, a(ij) and a(ji). Using these parameters, the solvent activities of the polystyrene 90,000 amu+methylcyclohexane system, and the total vapor pressures of the methylcyclohexane+ethylbenzene system were calculated. The latter system was compared to experimental data, giving qualitative agreement. Figure Solvent activities for the methylcylcohexane(1)+polystyrene(2) system at 316 K. Parameters aij (blue line) obtained with the AM1 method; parameters aij (pink line) from VLE data for the ethylbenzene+methylcyclohexane system. The abscissa is the polymer weight fraction defined as y2(x1)=(1mx1)M2/[x1M1+(1mx1)M2], where x1 is the solvent mole fraction and Mi are the molecular weights of the components.

Algorithms↗

PubMed1992

The physical and functional behavior of capture antibodies adsorbed on polystyrene.

Six monoclonal and two polyclonal antibodies to fluorescein (FLU) were affinity purified and immobilized on Immulon 2 polystyrene as capture antibodies (CAbs): (a) by passive adsorption at pH 9.6, (b) via a streptavidin bridge to a biotinylated carrier molecule, and (c) via an antiglobulin which had been previously adsorbed passively to the polystyrene. Data show that less than 3.0% of the binding sites of monoclonal CAbs and approximately 5-10% of those of polyclonal CAbs were capable of capturing antigen (FLU4.2-BSA) after passive adsorption. Immobilization of CAbs via an antiglobulin or a streptavidin bridge, resulted in the preservation of antibody binding sites to greater than 70% for some monoclonals although immobilization via the streptavidin bridge resulted in the highest number of functional sites/well. The data presented are consistent with studies on other adsorbed proteins which demonstrate that passive adsorption on polystyrene results in the loss of protein function. Furthermore, these data show that generally less than half of the binding sites of antibodies available in solution are available after solid-phase immobilization even when non-adsorptive methods are employed. Some polyclonal anti-FLU also have lower average avidity following passive adsorption compared with CAbs immobilization via a streptavidin bridge. Immunochemical studies revealed that adsorbed polyclonal-CAbs performed like monoclonals when tested with multivalent antigens (FLU10-IgA) but in an expected heterogeneous manner in Scatchard plots when tested using univalent FLU-insulin. This observation implied cross-linking of immobilized CAbs by the multivalent antigen. Because only 5-10% of adsorbed polyclonal CAbs are active, the survivors must be non-randomly distributed in clusters to explain the cross-linking. This was confirmed by scanning electron microscopy which gave rise to the hypothesis that antibodies which retain activity after adsorption, are those present in clusters, i.e., the functional adsorbed CAb is an antibody cluster. Data presented in this report on the behavior of adsorbed CAbs, and reviewed from the work of others for various adsorbed proteins, indicate that the method of passive adsorption at pH 9.6, which is widely used in popular microtiter ELISAs, and which has in many ways revolutionized immunoassay, is a method of protein denaturation. Assayists that utilize passive adsorption of proteins on hydrophobic supports as part of their research need to be cognizant of this phenomenon, while inventors of immunoassay should develop alternative methods of immobilization which do not destroy 90% of the functional activity of solid-phase reactant.

Adsorption↗

PubMed1983

Affinity of purified thrombin or antithrombin III for two insoluble anticoagulant polystyrene derivatives: I. In vitro adsorption studies.

In previous papers, we described insoluble polystyrene derivatives which exhibit a heparin-like antithrombic activity in plasma. In order to ascertain the heparin-like mechanism of this activity we have studied the interactions of thrombin and antithrombin III with two polymers of this series: sulphonated polystyrene and sulphonate-glutamic acid sulphonamide polystyrene. The adsorption was measured using purified enzyme and enzyme inhibitor and polymer beads whose average diameter was about 25 micron. The maxima of adsorption approximately correspond to a monolayer of protein. The results are discussed with respect to the most common isotherms used in chemisorption and the affinities of the enzyme and its inhibitor for both materials are evaluated: kT congruent to 10(7) (M/I)-1, kAT congruent to 3.10(5) (M/I)-1.

Adsorption↗