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PubMed2006

UV embossed polymeric chip for protein separation and identification based on capillary isoelectric focusing and MALDI-TOF-MS.

This paper demonstrates a ultraviolet (UV)-embossed polymeric chip for protein separation by capillary isoelectric focusing (CIEF) and identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The polymeric chip was replicated by a UV-embossing technique using a soft rubber mold. Five diverse widely investigated families of UV-cured formulations were examined for MALDI ionization efficiency of bovine serum albumin (BSA) samples spotted on the polymer surfaces. The signal and signal-to-noise ratio from the polyester formulation were each 12 times those obtained with PMMA (a commonly used polymer material for MALDI) at picomole sample concentration. A polyester chip was successfully used to carry out CIEF to separate proteins, followed by MALDI-TOF-MS identification. Issues related to the successful chip fabrication and protein separation and identification are discussed.

Electrophoresis, Capillary↗

PubMed1996

Raman chemical imaging: histopathology of inclusions in human breast tissue.

High-definition Raman chemical imaging microscopy is applied to the histopathological characterization of biopsied human breast tissue containing foreign polymer inclusions. The polymer material is found in a patient with a history of silicone implant breast reconstructive surgery. Silicone implants are, on occasion, anchored to the soft tissues of the chest with polyester patches. In the case studied here, the polyester anchors were incorporated into the patient's fibrous tissue surrounding the implant. High-definition Raman chemical imaging provides molecular-specific image contrast in the complex breast tissue matrix without the use of stains or dyes. This is the first example in which Raman spectroscopic imaging microscopy has been applied to pathology. A goal of this and future studies is to complement traditional histopathologic diagnoses of disease states utilizing vibrational spectroscopic imaging techniques.

Breast↗

PubMed1995

Large complexes of beta-poly(L-malate) with DNA polymerase alpha, histones, and other proteins in nuclei of growing plasmodia of Physarum polycephalum.

Of the various cell types in the life cycle of Physarum polycephalum, only the growing plasmodium contains the unusual polyester beta-poly(L-malate). The nuclei exhibit large complexes of this polymer with nuclear proteins, among them DNA polymerase alpha, histones, and HMG-like proteins. The complexes are indicated by the results of size exclusion chromatography and chemical cross-linking with 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride (EDC). After hydroxylaminolysis of the cross-linked polyester, the proteins are liberated and visualized on Western blots. The complexes of 1200-1400 kDa molecular mass exceed by far the size of free beta-poly(L-malate) and proteins. The observed variation in mass appears to be mainly a function of the kind and stoichiometry of the protein constituents and may explain the relatively high molecular mass in S phase and the low molecular mass during G2 phase of the mitotic cycle. The complexes are considerably stable at moderate ionic strength (100 mM KCl). Also, endogenous beta-poly(L-malate) does not exchange with added beta-[14C]poly(L-malate) during the lysis of the nuclei and the sample preparation. The complexes are dissociated at elevated concentrations of KCl, in the presence of spermine hydrochloride, or by treatment with DEAE/cellulose. Available evidence indicates that beta-poly(L-malate) may be involved in the maintenance of the plasmodial state of P. polycephalum.

Animals↗

PubMed2001

Novel degradable polymers combining D-gluconic acid, a sugar of vegetal origin, with lactic and glycolic acids.

To synthesize functionalized poly(lactic acid-co-glycolic acid)-based polyesters for biomedical and pharmaceutical applications such as controlled drug delivery, D-gluconic acid was considered as an interesting source of comonomer. Accordingly D-gluconic acid was used to synthesize novel 1,4-dioxane-2,5-diones with protected hydroxyl groups, namely 3-(1,2:3,4-tetraoxobutyl-di-O-isopropylidene)-dioxane-2,5-dione (5a) and 3-methyl-6-(1,2:3,4-tetraoxobutyl-di-O-isopropylidene)-dioxane-2,5-dione (5b). The ring-opening homopolymerization and copolymerization of these cyclic dilactones with DL-lactide provided novel degradable polyesters with higher glass transition temperatures than poly(lactic acid-co-glycolic acid) polymers.

Biocompatible Materials↗

PubMedDate not supplied

Biosynthesis and properties of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) polymers.

In support of programs to identify polyhydroxyalkanoates with improved materials properties, we report on our efforts to characterize the mechanical and thermal properties of copolyesters of 3-hydroxybutyrate (3HB) and 3-hydroxyhexanoate (3HHx). The copolyesters, having molar fraction of 3HHx ranging from 2.5 to 35 mol % and average molecular weights ranging from 1.15 x 10(5) to 6.65 x 10(5), were produced by fermentation using Aeromonas hydrophila and a recombinant strain of Pseudomonas putida GPp104. The polymers were chloroform extracted and characterized by solution-state and solid-state nuclear magnetic resonance (NMR) spectroscopy and a variety of mechanical and thermal tests. Solution-state (1)H NMR data were used to determine polymer composition-of-matter, while solution-state (13)C NMR data provided polymer-sequence information. Solvent fractionation and NMR spectroscopic characterization of these polymers showed that polymers containing up to 9.5 mol % 3HHx had a Bernoullian compositional distribution. By contrast, polymers containing more than 9.5 mol % 3HHx had a bimodal polymer composition. Solvent fractionation of these 3HHx-rich polyesters produced two polymer fractions, each of which was again consistent with Bernoullian polymerization statistics. Solid-state NMR relaxation experiments provided insight into aging in poly(3HB-co-3HHx) copolymers, demonstrating increased polymer-chain motion with increasing 3HHx content. The elongation-to-break ratio in the polyesters increased with increasing molar fraction of 3HHx monomers. Aging properties of the poly(3HB-co-3HHx) copolymers were very similar to copolymers of 3HB and 3-hydroxyvalerate (3HV). However, poly(3HB-co-3HHx) exhibited increased activation energy to thermal degradation with increasing 3HHx content.

3-Hydroxybutyric Acid↗

PubMed2006

Polycondensation of dicarboxylic acids and diols in water catalyzed by surfactant-combined catalysts and successive chain extension.

Direct dehydration polycondensation of dicarboxylic acids and alcohols was carried out by surfactant-combined Brønsted and Lewis acids. This procedure did not require the removal of water, because the esterification was established at the interface of the emulsion in water. Emulsion polycondensations of 1,9-nonanediol (1,9-ND) and dodecanedioic acid (DDA) (the molar ratio of dicarboxylic acid to diol = 1:1) were carried out at 80 degrees C for 48 h in the presence of 16 wt % DBSA. The corresponding polyester (M(w) = 10.1 x 10(3)) was obtained in an excellent yield (99%). Chain extension in the emulsion was carried out using hexamethylene diisocyanate as the chain extender. SEC measurements indicated the expected shift to higher molecular weight region (M(w) = 11.4 x 10(3), M(w)/M(n) = 3.4) compared with parent polyester (M(w) = 4.5 x 10(3), M(w)/M(n) = 2.2).

Alcohols↗

PubMed1999

Construction of a thread coater and use of azocasein release To characterize the sealant coat porosity of fibers coated with latex biocatalytic coatings

A single-stage annular fiber coating method with co-current dry-air drying at 30 degrees C has been developed for multilayer coating of 128 &mgr;m diameter polyester thread (yarn) with latex films as a model for enzyme immobilization and development of a filament biocatalytic filter. Acrylic vinyl acetate polymer coatings were sequentially metered onto the fibers by the combination of a flexible squeegee and a red rubber annulus. The thread coater can operate over a range of 0.07-1.37 m/min thread velocities while delivering a nearly constant and reproducible polymer loading of 30. 8 +/- 1.3 mg/m. A 100% polyester, 278.9 denier thread was precoated with latex to generate an approximately 369 denier sealed filament. The filament was then coated with a latex + sulfanilamide-azocasein mixture and sealed with a polymer top coat. The permeability of the polymer sealant top coat was characterized using entrapped azocasein as a tracer molecule and monitoring the azocasein release upon rehydration of the coated threads. Azocasein release rate decreased with curing time at 30 degrees C until 2 days and was invariant after 2-3 days of curing. A 282 mOsm rehydrating solution was sufficient to suppress increased azocasein release due to top coat blistering. No enhancement in the permeability of the top coat was observed when high molecular weight water soluble polymers (WSPs) were used as fillers. This probably results from the low WSP to latex ratio used (0.05-0.1) and the slow rate of WSP leaching compared to the release of azocasein. A method using 60-120 mesh silica was also developed to study the effect of mechanical abrasion of the coated threads as measured by azocasein release kinetics.

Journal Article↗

PubMed2005

Convenient synthesis of 1 --> 3 C-branched dendrons.

A facile, efficient synthesis of 1 --> 3 C-branched polyamide dendrons is described. Treatment of acryloyl chloride with 1 --> 3 C-branched amines, e.g., di-tert-butyl 4-[2-(tert-butoxycarbonyl)ethyl]-4-aminoheptanedioate, gave the corresponding acrylamides in high yields, which upon reaction with nitromethane generated the homologated nitroalkane-polyesters. Finally, nitroalkane alkylation with 2 equiv of the acrylamides, followed by nitro group reduction, afforded the desired amino-polyesters.

Journal Article↗

PubMed2006

Surface microcracks decoration and disclination defects of wholly aromatic liquid crystalline copolyesters.

An intensive study has been conducted to map the director fields of disclination of nematic liquid crystalline copolyesters. In this study, films of two wholly aromatic main-chain polyesters containing para- (ABA/MH/TFTA) and meta-linkages (ABA/MH/TFIA) (ABA, p-acetoxybenzoic acid; MH, maleic hydrazine; TFTA, tetrafluoroterephthalic acid; TFIA, tetrafluoroisophthalic acid) were synthesized to investigate the effects of kinks on liquid crystallinity, disclination strength (S), and surface microcracks decoration. These two copolyesters were prepared by in-situ thin film polymerization and characterized by polarizing light microscope, wide-angle X-ray diffraction, as well as "rotational isomeric states" (RIS) Metropolis Monte Carlo (RMMC) simulation. An optical microscope shows that the surface microcracks forms in the nematic-mosaic texture during a rapid quenching. The ABA/MH/TFTA film exhibits disclination strength with S = +1 and S = -(1)/(2); however, disclination strengths with S = +/-1 have been observed in the ABA/MH/TFIA system. To our best knowledge, this is the first paper reporting the effects and evidence of kink (meta and para moieties) on topological defect of disclination. In addition, the RMMC analysis supports the liquid crystal formation in both polyester films with a persistence ratio greater than 6.42.

Journal Article↗

PubMed2006

Influence of copolymer configuration on the phase behavior of ternary blends.

The influence of copolymer configuration on the phase behavior of various ternary polymer blends containing a crystallizable polyester, a noncrystallizable polyether, and an acrylic random copolymer of different chain configuration was investigated. In these ternary blends, the acrylic random copolymer is typically added to control rheological properties at elevated temperatures. In fact, the acrylic random copolymers composed of various compositions of MMA and nBMA were found to have different miscibility with polyester as well as polyether, leading to substantially different phase behavior of ternary blends. Remarkable temperature dependence was also found. The mean-field Flory-Huggins theory for the free energy of mixing, extended to ternary polymer blends, was adopted for predicting phase diagrams where the exact spinodal and binodal boundaries could be calculated. Phase diagrams of ternary blends, predicted by the Flory-Huggins formulations and related calculations, were in good agreement with experimental phase diagrams. The differences observed in the rheological processes of various ternary blends with different acrylic copolymers were directly related to changes in miscibility, associated phase behavior, and chain configuration.

Journal Article↗

PubMed2001

Tetanus toxoid loaded nanoparticles from sulfobutylated poly(vinyl alcohol)-graft-poly(lactide-co-glycolide): evaluation of antibody response after oral and nasal application in mice.

PURPOSE: Aim of the study was the evaluation of the potential of novel tetanus toxoid (TT) loaded nanoparticles (NP) for electing an immune response in mice against TT. METHODS: Six week-old female Balb/c mice were immunized by oral (p.o.), nasal (i.n.) and intraperitoneal (i.p.) application of TT NP loaded by adsorption. As polymer a novel polyester, sulfobutylated poly(vinyl alcohol)-graft-poly(lactide-co-glycolide), SB(43)-PVAL-g-PLGA was used. Blood samples were collected 4 and 6 weeks after immunization and assayed for serum IgG- as well as IgA antibody titers by ELISA. NP formulations varying in size and loading were compared to alum adsorbates as well as to TT solutions. RESULTS: Both, p.o. and i.n. administration of TT associated NP increased serum titers up to 3 x 10(3) (IgG) and 2 x 10(3) (IgA). While small NP induced significantly higher titers then larger ones after oral administration, intermediate NP induced antibodies after nasal application. Of the mucosal routes investigated, i.n. seems to be more promising compared to p.o. immunization. CONCLUSIONS: Antigen loaded NP prepared from surface modified polyesters combined with CT show considerable potential as a vaccine delivery system for mucosal immunization. The results warrant further experiments to explore in more detail the potential use of NP as mucosal vaccine delivery system.

Administration, Intranasal↗

PubMed1994

Chemical interactions between drugs containing reactive amines with hydrolyzable insoluble biopolymers in aqueous solutions.

Chemical reactions between drugs containing reactive amines with hydrolyzable polymers in buffer solutions were investigated. Phenylalkylamines with increasing nucleophilic reactivity were used as model drugs. Solutions of phenylalkylamines were reacted heterogeneously with representative biodegradable polyanhydride and polyester powders in various pH solutions, and the recovery of the amines from the solutions was determined. Poly(sebacic acid), a reactive polyanhydride, reacted by amide formation with the tested amines and their respective HCl salts when exposed to physiologic pH (pH 7.4). However, at pH 5.0 no interaction occurred. The aromatic polyanhydride, PCPP, and the polyesters based on lactic acid and caprolactone did react with the amine derivatives at pH 7.4, but at a slower rate. The reaction can be avoided with appropriate salt derivatives of the amines.

Amines↗

PubMed2004

Membrane-based PDMS microbioreactor for perfused 3D primary rat hepatocyte cultures.

To improve primary adult rat hepatocyte cultures, two types of PDMS microbioreactors containing a membrane, used as a scaffold for the attachment of cells, were built: one with a commercially-available polyester membrane, the other with a PDMS membrane (5 x 5 microm hole sizes) made in our laboratory. In that way, the relative surface area between blood perfusion and hepatocytes seen in vivo was mimicked and as cells were bathed in both sides by the culture medium they expressed much higher functions. A new technique to build such PDMS membrane was created. With this technique we could build various PDMS membranes with down to 5 x 5 microm holes and with thickness even below 20 microm. During the fifteen days of perfusion in these microbioreactors, good cell attachment then cell reorganization was observed. Moreover compared to static cultures in tissue-culture-treated dishes and in cultures in inserts with the same polyester membranes, seven and two times increases in the albumin secretion by the cultured primary rat adult hepatocyte were demonstrated, respectively. Ammonium removal also increased 7 times in perfused cultures compared to static cultures. These new microbioreactors, which closely mimic the in vivo liver architecture, revealed themselves to be very promising tools towards future applications in drug screening or liver tissue engineering.

Animals↗

PubMed2000

Patch testing with neomycin sulfate.

The recommended patch test concentration of neomycin sulfate is 20% in petrolatum applied occluded for 48 h (2 days [D]). In the current study, the efficiency of such a test is compared to results with other techniques using lower allergen dose than obtained by approximately 20 microl of the 20% substance. Efficiency of petrolatum and demineralized water as vehicles are compared. 16 neomycin-sulfate positive subjects were retested with serial doses ranging from 0.4 to 0.0085 mg/cm2 neomycin sulfate in cellulose printed on polyester squares and applied by both tapes and plastic foils. Additionally, tests were performed with the 20% petrolatum substance in Finn Chambers. Tests containing the 20% substance in petrolatum and in water were applied directly with transparent foils. Readings ranged from 3 to 264 h (11D) following applications. Results show that foil applications of a polyester square dose, that is 7% of the dose obtained with the 20% substance, distinguished between perfusion of subjects who were visually positive and not with any test in the study. With the same test technique and visual assessments, 2 subjects were false-negative but developed doubtful test responses with the Finn Chambers.

Dermatitis, Allergic Contact↗

PubMed2000

MALDI-MS and colorimetric analysis of diisocyanate and polyol migrants from model polyurethane adhesives used in food packaging.

The identification of the migrants, into food simulants, from a series of polyurethane adhesives used in the manufacture of plastic film laminates for use in common food packaging is described. Commercial materials, based on four different model adhesive systems, were prepared by an industrial collaborator. The MALDI-MS fingerprint patterns of the three polyether and one polyester polyol components of these adhesives were obtained for reference purposes. The decrease in the level of diisocyanate as a migrant versus time after lamination was confirmed by colorimetric measurements. The migration of the standard polyol samples through polyethylene pouches into water at 70 degrees C has been demonstrated and also the attenuation effect for different polyols. Cured laminates in the form of pouches were used to carry out the migration experiments into distilled water, inside the pouch, at 70 degrees C over a period of 2 h. Comparison of the migration results from the food packaging laminates with those from the polyethylene film confirmed the migration of unreacted polyol components for the polyether-based systems. Cyclic oligomers from the polyol starting materials were identified as the migrants from the polyester-based adhesive.

Colorimetry↗

PubMed2002

Rapid prototyping for injection moulded integrated microfluidic devices and diffractive element arrays.

This paper describes two fabrication procedures that makes it possible to design, fabricate and injection mold a microfluidic system with an on board coupling element or an optical array platform in less than four hours. Epoxy masters for the array and a single diffractive element were produced using conventional soft lithography techniques and a commercially available UV curable epoxy. The fabrication of the master for the integrated microfluidic device utilized the surface chemistry of polyester and its interaction with the anionic surfactant sodium dodecyl sulfate (SDS), to selectively inhibit the adhesion between the epoxy and the polyester film during the curing reaction. The transfer of a microfluidic design and the required coupling element (632 nm holographic grating) along the base of the channel was completed in a single step. The turnaround time from design to injection molded device whether a microchannel or array was 3.5 h.

Journal Article↗

PubMed1998

Intraoperative transmission of blood-borne disease in haemophilia.

Because HIV and hepatitis B and C infection can be transmitted by exposure to infected blood or blood components, orthopaedists are at risk for HIV and hepatitis infection during surgical procedures. Thus, care must be taken to protect themselves from transmission of HIV and the hepatitis virus. The following precautions are recommended: double latex gloves, changed hourly, or a combination of cloth and latex gloves, enclosed hood and face-masks and operative isolator with umbilical-cord aspirator; knee-length impermeable gowns of high-count polyester weave or plastic-lined nonwoven spun-lace polyester; a combination of shoe-covers that provide waterproof coverage as high as the knee; and disposable drapes. If a member of the operating team is inadvertently pricked or cut, the wound should be washed immediately with iodine, soap and water. If the injured person has been immunized for the hepatitis B (and has adequate titres), or is positive for hepatitis B surface antigen or antibody, no further treatment is necessary. Otherwise, two doses of hepatitis B immune globulin should be given, 5 mL immediately and 5 mL after 1 month. Because HIV infection can be transmitted by exposure to infected blood, orthopaedic surgeons are also at risk for HIV infection. Prospective studies suggest that this risk is very low; nevertheless, healthcare workers need to adhere rigorously to the aforementioned infection-control precautions to minimize the risk of exposure to blood.

Acquired Immunodeficiency Syndrome↗

PubMed2001

Olyset Net efficacy against pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus after 3 years' field use in C te d'Ivoire.

Pyrethroid-impregnated bednets are advocated for personal protection against malaria vectors. To avoid the need for periodic re-treatment, it would be advantageous to have nets that retain insecticidal efficacy for years and withstand repeated washing. Such a type of commercially produced bednet with permethrin 2% incorporated in polyethylene fibres (trademark Olyset Net supplied by Sumika Life-Tech Co., Osaka, Japan) was evaluated against mosquitoes in veranda-trap huts at Yaokoffikro, near Bouaké, C te d'Ivoire, by standard WHOPES phase II procedures. Four Olyset Nets were compared with a standard untreated polyester net as control. They comprised three examples previously used in a village for over 3 years (one washed, one dirty, one very dirty) and a previously unused Olyset Net, newly unwrapped, from the same original batch. Bioassays with 3 min exposure of susceptible Anopheles gambiae Giles (Diptera: Culicidae) gave >99% mortality of female mosquitoes tested on the 'new' Olyset Net. The used Olyset Nets gave mortality rates averaging 83% for the washed net, 85% for the dirty net and 55% for the very dirty net (within 24-h following 3 min exposure). Thus, Olyset Nets were found to remain remarkably effective against susceptible An. gambiae for at least 3 years under field conditions. Wild pyrethroid-resistant populations of Culex quinquefasciatus Say and An. gambiae (savanna cytotype with 96% kdr) were assessed during June-August 1999 for their responses to sleepers protected by nets in the experimental huts. With regard to hut entry by foraging female mosquitoes, Olyset Nets showed some deterrency against An. gambiae (44% reduction by the new net, approximately 20% by the dirty nets, none by the washed net), but not against Cx. quinquefasciatus. Among mosquitoes entering the hut with untreated control net, 30-34% tried to leave (exophily) but were caught in the verandah trap. The permethrin repellency of Olyset Nets increased exophily by 19% for An. gambiae and 14% for Cx. quinquefasciatus. Blood-feeding rates were 16% An. gambiae and 35% Cx. quinquefasciatus in the hut with sleeper under the untreated net (showing considerable prevention of biting), 22-26% of both species in huts with washed or dirty used Olyset Nets (not significantly different from control), while the biting success rate of Cx. quinquefasciatus (but not kdr An. gambiae) was more than halved by the 'new' Olyset Net. Mortality rates of pyrethroid-resistant An. gambiae and Cx. quinquefasciatus from the huts were, respectively, 3% and 8% with the untreated polyester net, 27.5% and 17% with the 'new' Olyset, 15% and 17.5% with the washed Olyset, 16-25% and 17-20% with dirty old Olyset Nets. Kill differences between nets are significantly different for both An. gambiae and Cx. quinquefasciatus. Unfortunately the washed used Olyset Net showed least activity against resistant mosquitoes, despite its greatest activity against susceptible An. gambiae. In each case there was evidence that a high proportion of mosquitoes failed to feed through the net (many of them dying from starvation when they could not leave the closed hut), with indications that dirty Olyset nets enhanced this protective value.

Animals↗