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PubMed2004

Matrix-assisted and polymer-assisted laser desorption/ionization time-of-flight mass spectrometric analysis of low molecular weight polystyrenes and polyethylene glycols.

Recently, matrices based on oligomers of dioxin and thiophene (polymer-assisted laser desorption/ionization (PALDI)) have been described for mass spectrometric (MS) analysis of low molecular weight compounds (Woldegiorgis A, von Kieseritzky F, Dahlstedt E, Hellberg J, Brinck T, Roeraade J. Rapid Commun. Mass Spectrom. 2004; 18: 841-852). In this paper, we report the use of PALDI matrices for low molecular weight polymers. An evaluation with polystyrene and polyethylene glycol showed that no charge transfer ionization occurs. Ionization is mediated through metal ion adduction. Comparison of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) data for two very low molecular weight polymers with data obtained from size-exclusion chromatography (SEC) revealed a systematic difference regarding mean molecular weight and dispersity. Further, the mass spectra obtained with PALDI matrices had a higher signal-to-noise ratio than the spectra obtained with conventional matrices. For polymers with higher molecular weights (>1500 Da), the conventional matrices gave better performance. For evaluation of the MALDI spectra, three non-linear mathematical models were evaluated to model the cumulative distributions of the different oligomers and their maximal values of Mw, Mn and PDI. Models based on sigmoidal or Boltzmann equations proved to be most suitable. Objective modeling tools are necessary to compare different sample and instrumental conditions during method optimization of MALDI analysis of polymers, since the bias between MALDI and SEC data can be misleading.

Biopolymers↗
PubMed2006

The effect of tetrahydrofuran as solvent on matrix-assisted laser desorption/ionization and electrospray ionization mass spectra of functional polystyrenes.

It is demonstrated that tetrahydrofuran (THF) should be used with caution as a solvent in polymer sample preparation for matrix-assisted laser desorption/ionization (MALDI) analyses. The presence of peroxides in THF may cause the oxidation of chemically active groups. This effect is illustrated in the case of S-containing polystyrene derivatives. The oxidation of the trithiocarbonate group resulted in the formation of poly(styrene)sulfonic acids, R(CH(2)CHPh)(n)SO(3)H, which was detected in negative mode by MALDI and electrospray ionization (ESI) methods after the samples remained in THF for several hours.

Furans↗
PubMed1994

Binding of biotinylated DNA to streptavidin-coated polystyrene latex.

The binding of 5'-end biotinylated DNA fragments was compared between streptavidin (SA)-coated commercial M-280 magnetic latex particles with a diameter of 2.8 microns and adsorption-coated polystyrene (PS) latex standard particles whose diameter is 0.272 microns. Amino acid analysis showed the protein content of the commercial particles to correspond to 4x monolayer coverage, while the adsorption-coated PS particles displayed monolayer coverage, or 8 pmol/cm2. A fluorescence-based method was developed to quantify the adsorption of FITC-labeled SA, biotin, and biotinylated DNA. The validity of the method was substantiated for the labeled protein by both amino acid analysis and a colorimetric protein assay. While the specific binding of biotin was 0.38 mol per mole of SA on the adsorption-coated 0.272-microns particles and slightly higher (0.6 mol per mole SA) on the 2.8-microns particles, the specific binding of the bulky biotinylated 300-bp DNA was more favorable on the smaller particle (0.12 mol per mole SA for 0.272 microns versus 0.04 mol per mole SA for 2.8 microns).

Adsorption↗
PubMed1994

Molecular sieving of polystyrene carboxylate of a diameter up to 10 microns in solutions of uncrosslinked polyacrylamide of M(r) 5 x 10(6) using capillary zone electrophoresis.

Capillary zone electrophoresis of polystyrene carboxylate (PSC) up to 10 microns in diameter in 0.1 to 0.9% solutions of uncrosslinked polyacrylamide (PA) of M(r) 5 x 10(6) demonstrates effective molecular sieving in that medium. The reduced mobility, however, is not constant in Tris-borate-EDTA (1x TBE) buffer containing the polymer but increases in proportion to the load of PSC and inversely to the concentration of PA unless the TBE concentration is increased 10-fold or 50 mM 3-[(3-cholamidopropyl)dimethylammonio]propanesulfonic acid is added to the solution or in the absence of PA. Both the Ferguson plots [log(mobility) vs PA concentration] of PSC obtained at various PSC loads and the effects of the dissociating conditions, high ionic strength and detergent, signify that the variable mobilities are those of different PSC aggregation states. Thus, only the fully associated or dissociated states of PSC provide mobilities that are constant independently of PSC load. The study shows that the information inherent in Ferguson plots regarding particle and fiber properties can be exploited for particles up to 10 microns in diameter by capillary zone electrophoresis in polymer solutions even if these particles form various aggregation states. Thus, such an analysis appears feasible in application to biologically relevant and functional complexes such as subcellular-sized particles or DNA-protein complexes, providing that these particles maintain their integrity and functionality under the selected electrophoretic conditions.

Acrylic Resins↗
PubMed1995

Assessment of adsorption and adhesion of proteins to polystyrene microwells by sequential enzyme-linked immunosorbent assay analysis.

Originally developed as a method for estimating the solid-phase concentration of an adsorbed protein, sequential enzyme-linked immunosorbent assay (ELISA) analysis (P. A. Underwood and J. G. Steele (1991) J. Immunol. Methods 142, 83-94) is also useful for assessing other aspects of protein-surface interactions without radioactively labeled reagents. The method provides a way to compare protein adsorption on various microwell surfaces and to track adhesion of the protein throughout an assay's wash and incubation steps. In cases where adsorption complies with Langmuir-type binding and protein desorption is minimal, sequential ELISA data can be analyzed with a mathematical model to quantitatively estimate the microwell's protein-binding capacity. Even for protein-surface interactions where the mathematical model is not appropriate, characteristics of sequential ELISA binding data qualitatively differentiate between initial adsorption with subsequent desorption and poor initial adsorption of the protein. Using this method, we analyzed the binding of three proteins (rabbit immunoglobulin G, bovine serum albumin, and horse spleen ferritin) to four types of polystyrene microwell surfaces (Immulons 1, 2, 3, and 4). In addition, we examined differences in protein adhesion to the four surfaces when Tween 20 was omitted from the assay's wash buffer or when fewer washes were used.

Absorption↗
PubMed1995

The use of 96-well polystyrene plates for DNA hybridization-based assays: an evaluation of different approaches to oligonucleotide immobilization.

A reliable, simple, and cost-effective method for the immobilization of relatively short (12-30 mer) oligonucleotide probes to 96-well polystyrene plates was required in our laboratory for use in DNA hybridization-based assays. We compared three different approaches to achieve this immobilization. Two of them are modifications of previously published procedures, requiring the use of modified oligonucleotides and/or modified plates. These were compared to a method developed in our laboratory, whereby passive immobilization occurs by incubation in the presence of salt or a cationic detergent. While all methods resulted in the productive binding of the DNA probes and could therefore be used for hybridization, only the passive immobilization approach met our strict performance criteria and was implemented for use in our DNA genotyping laboratory. It was found that the immobilization in the presence of cationic detergents takes place via a unique mechanism.

Base Sequence↗
PubMed1996

Binding of biotinylated DNA to streptavidin-coated polystyrene latex: effects of chain length and particle size.

The binding of 5'-end biotinylated DNA, ranging in size from 100 to 5000 base pairs, was studied using streptavidin-coated polystyrene latex particles with diameters between 0.944 and 0.090 micron. The experimental binding constants and forward rate constants of this solid-phase reaction were determined to be several orders of magnitude lower than values for the biotin-streptavidin interaction in solution as expected and were shown to depend on the size of both ligand and substrate. An observed inflection in the binding constant of the biotinylated DNA appeared around 1000 base pairs, possibly indicating different surface orientations of the macroligand above and below this critical size. This effect was more pronounced for the smaller latex particles used in this study and highlighted possible differences in the surface arrangement of streptavidin on the differently sized particles. Diffusion limitation to the binding reaction was found to be significant in all cases. In this present work, an exponential relationship was established between the experimental binding constant and the number of base pairs in the biotinylated DNA. This relationship possibly provides a means to predict capacity and binding speed in cases where adsorption, purification, and release of larger DNA chains are required.

Bacterial Proteins↗
PubMed2002

An unprecedented surface oxidation of polystyrene substrates by wet chemistry under basic conditions.

The surface of polystyrene substrates has been modified by wet chemistry consisting of a treatment with sodium hydroxide in a water-methanol solution at 50 degrees C for 15 h, under air atmosphere. The resulting samples were analyzed by XPS and AFM. The surface functional groups (hydroxyl and carboxyl functions) were assayed by radiolabeling. All the results are consistent with a surface oxidation process.

Microscopy, Atomic Force↗
PubMed1981

Biologic gastric emptying time using Tc-99m TETA polystyrene resin in various clinical conditions.

In 82 subjects 82 gastric emptying studies using Tc-99m triethylene tetramine polystyrene resin were retrospectively evaluated. All six patients with diabetic gastroenteropathy (GE) had delayed biologic gastric emptying time (BGET) that responded well to metoclopramide (MP) injection. In 11 diabetics without GE, only two had prolonged BGET with good response to MP. All 11 patients with gastric outlet obstruction also had prolonged BGET, but no significant response to MP was found in 7 studies. Five of 7 patients with active gastric ulcer had delayed BGET. Three of ten patients with previous Billroth I or II operation had accelerated BGET, and 3 of 9 patients with previous vagotomy had delayed BGET with good response to MP. Markedly prolonged BGET with significant response to MP was also observed in 3 patients with disordered gastric motility. Delayed BGET was found in one patient with bile reflux gastritis and in 2 of 6 patients with reflux esophagitis. No prolongation of BGET was observed in 6 symptomatic patients whose radiographic and endoscopic examinations were negative. BGET studies with this agent appear to be reliable and very helpful in the management of patients with gastric symptoms and for obtaining an objective measurement of the response to therapy.

Adolescent↗
PubMed1983

Non-specific binding of transferrin and lactoferrin to polystyrene culture tubes: role of the radioligand.

While evaluating the role of iron-binding glycoproteins on the in vitro uptake of 67Ga and 59Fe by tumor cells, it was observed that these radiometals bind to polystyrene culture tubes in the presence of transferrin or lactoferrin. The amount of 67Ga or 59Fe bound to the tube increases with glycoprotein concentrations up to 20 microgram/ml and decreases thereafter. This biphasic response is a reflection of metal-protein affinity and is greatest for 59Fe-lactoferrin. With 125I-labeled transferrin and lactoferrin, the amount of tube-bound radioactivity was inversely dependent on the glycoprotein concentration suggesting that glycoproteins bind to a limited number of binding sites on the tube wall. Approximately 10(13) glycoprotein molecules were bound per tube with an affinity constant of 1.89 X 10(7) 1/M for transferrin and 1.08 X 10(7) l/M for lactoferrin. These sites are not specific since addition of albumin inhibited the binding of radiolabeled glycoproteins to the tube. In the light of these observations, caution is required in interpreting results of cell culture experiments which have not directed attention to protein-plastic interaction.

Albumins↗
PubMed1991

Pretreatment of formula with sodium polystyrene sulfonate to reduce dietary potassium intake.

Sodium polystyrene sulfonate (SPSS) is commonly administered for the acute and chronic treatment of hyperkalemia. Its oral intake is complicated by poor compliance due to multifaceted reasons. We therefore analyzed a method of reducing potassium (K) in formula by pretreatment with SPSS. If effective, this would bypass complications of enterally administered SPSS and provide low-K formula. Thirteen formulas and nutritional supplements were pretreated with SPSS to determine if one could bind K and provide formulas with decreased K contents. Using an SPSS concentration of 1 g/l mEq K in the formula, 62 +/- 2.6% (P less than 0.01, mean +/- SEM) of the K was removed in 30 min, while the sodium (Na) concentration was increased by 234 +/- 37% (P less than 0.01). Analysis suggests that the disproportionate increase in Na is due to exchange for calcium (Ca) and magnesium (Mg), interaction with proteins, and Na suspended with SPSS in the formula. Thus, SPSS pretreatment of formula is an effective method of making low-K formula, but the increase in Na exceeds the K reduction. Attention to possible complications of increased Na intake as well as decreased Ca and Mg intake is warranted.

Humans↗
PubMed1991

Some observations on the binding properties of alfalfa mosaic virus to polystyrene and its significance to indirect ELISA.

The adsorption and retention properties of native (unfixed) and glutaraldehyde-fixed alfalfa mosaic virus (AMV) antigens to the polystyrene of ELISA plates were studied using [35S]-labelled virus preparations. It was shown that adsorption was a temperature-dependent, relatively slow process which varied between different AMV isolates. The amount of virus antigen adsorbed was dependent on the type and pH of the suspending buffer. Although native virus antigen adsorbed very efficiently at high pH when the particles had dissociated, significant amounts also adsorbed at pH 7.0, or lower. However, glutaraldehyde-fixed virus particles which retained their integrity even at pH as high as 9.6, adsorbed much more efficiently than native virus antigen above pH 9.0, but hardly at all around pH 7.0. The wide variation in adsorption of AMV antigen to microtitre plates under even slightly different conditions had significant influence on ELISA readings, which calls for extreme caution in interpreting serological results from indirect ELISA when antigen is used to coat the microtitre plates.

Adsorption↗
PubMed1992

Effect of subinhibitory concentrations of cefamandole and cefuroxime on adherence of Staphylococcus aureus and Staphylococcus epidermidis to polystyrene culture plates.

The ability of cefamandole and cefuroxime to inhibit adherence of staphylococci to polystyrene culture plates was tested in an in vitro assay using eight strains each of Staphylococcus aureus and Staphylococcus epidermidis. The results indicated that subinhibitory concentrations of cefamandole and cefuroxime altered the adherence ability of both staphylococcal species, inhibition of adherence being more marked in the presence of cefamandole. It may be important to consider antiadherence properties in association with bactericidal activity when selecting agents for antibiotic prophylaxis.

Bacterial Adhesion↗
PubMed1993

Colonic necrosis following sodium polystyrene sulfonate (Kayexalate)-sorbitol enema in a renal transplant patient. Report of a case and review of the literature.

The authors present the case of a patient who developed near total colonic necrosis shortly after renal transplantation. The onset of symptoms was temporally related to the administration of sodium polystyrene (Kayexalate; Sanofi Winthrop Pharmaceuticals, New York, NY)-sorbitol enemas for treatment of hyperkalemia. Three similar cases have been reported in the literature. The presence of uremia and the use of sorbitol appear to be common denominators in the pathophysiology of this complication. It is suggested that Kayexalate-sorbitol enemas be avoided in renal transplant patients.

Colon↗
PubMed1987

The neutrophil response to polystyrene microspheres bearing defined surface functional groups.

Luminol-induced chemiluminescence (CL) and phagocytosis by human neutrophils was studied using polystyrene microsphere latices as particulate stimuli. Chemiluminescence and phagocytosis parameters were measured for particles bearing carboxyl, hydroxyl, and amino groups, as well as for the underivatized microspheres. The kinetic curves of CL were bimodal, and curve parameters were evaluated for both the early- and late-phase responses. Significant differences were found among the particle surfaces studied. Underivatized particles elicited the greatest response, particles with the amino group stimulated PMN the least, carboxyl- and hydroxyl-group-bearing particles elicited intermediate magnitudes of response. Phagocytosis data were in good agreement with that obtained from CL measurements. These data provide further evidence in favor of the hypothesis that, in protein-free systems, hydrophobic particles are more readily phagocytosed. Additionally they demonstrate that electrostatic interactions are not a significant factor for neutrophil-particle contact.

Adult↗
PubMed2003

Controlled release of epidermal growth factor (EGF) from EGF-loaded polymeric nanoparticles composed of polystyrene as core and poly(methacrylic acid) as corona in vitro.

Polymeric nanoparticles composed of polystyrene (PS) as core and poly(methacrylic acid) (PMA) as corona were prepared by the dispersion copolymerization. The potential of the nanoparticles as carriers for recombinant human epidermal growth factor (EGF) was investigated. The nanoparticles showed monodispersity and good water-dispersibility. The loading content of EGF to the nanoparticles was very high due to electrostatic interaction between EGF and nanoparticles. EGF was released as a pseudo-zero order pattern after initial burst effect. The nanoparticles were sufficient for A431 cells proliferation.

DNA↗
PubMed2002

A piezoelectric immunoassay based on self-assembled monolayers of cystamine and polystyrene sulfonate for determination of Schistosoma japonicum antibodies.

A piezoelectric immunosensor based on an improved immobilization strategy combining self-assembled monolayers (SAM) of cystamine (Cys) and polystyrene sulfonate (PSS) has been developed for the determination of Schistosoma japonicum antibodies (SjAb) in rabbit serum. Cys SAM were first applied to the gold electrode surface of the crystal, serving as a positively-charged base. Schistosoma japonicum antigen (SjAg) was then electrostatically immobilized on the crystal by means of a negatively-charged PSS layer. When sealed by use of an appropriately selected blocking reagent for BSA and normal rabbit serum (NRS), non-specific adsorption could be substantially reduced. The immunosensor was used to determine SjAb in optimized buffer medium with addition of poly(ethylene glycol) (PEG), which served as an immunoreaction enhancer. It was shown experimentally that SjAg immobilized by the Cys-PSS adsorption procedure had higher immunological activity or binding efficiency than those immobilized by the glutaraldehyde (GLU) binding or direct attachment procedures. The immunosensor developed had satisfactory sensitivity and detection limit, and regeneration of the piezoelectric quartz-crystal was easy. Analytical results obtained with infected rabbit serum samples indicated that the proposed immunosensor is a promising alternative for qualitative and quantitative determination of SjAb in clinical diagnosis of infection with Schistosoma japonicum.

Adsorption↗