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1.
Talanta ; 201: 185-193, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31122410

RESUMO

A novel, simple, sensitive, and precise spectrofluorometric assay of cancer antigen [CA 125] is described. This modality is based on monitoring the quenching of the luminescence intensity at 790 nm of the phthalocyanine fluorophore, in a nanocomposite comprising the fluorophore and cationic polystyrene, which results from interaction with CA 125. The remarkable quenching of the luminescence intensity of the Ni-phthalocyanine complex doped in PS matrix by various concentrations of CA 125 was successfully utilized as an optical sensor for the determination of CA 125 in different serum samples of ovarian disease. The performance of the designed biosensor is determined through monitoring the quenching of the luminescence intensity at 790 nm by cancer antigen 125 after excitation at 685 nm, pH 7.3 in water. The calibration plot was achieved over the concentration range 1.0 × 10-2 - 127 U mL-1 CA-125 with a correlation coefficient of 0.99 and detection limit of 1.0 × 10-4 U mL-1. The mechanism of the interaction between the nano thin film nickel(II)phthalocyanine and CA-125 was discussed. A significant correlation between the proposed method for the assessment of CA 125 and the standard method was applied to patients and controls.


Assuntos
Técnicas Biossensoriais/métodos , Antígeno Ca-125/sangue , Corantes Fluorescentes/química , Indóis/química , Proteínas de Membrana/sangue , Nanocompostos/química , Poliestirenos/química , Biomarcadores Tumorais/sangue , Feminino , Fluorescência , Corantes Fluorescentes/síntese química , Humanos , Indóis/síntese química , Limite de Detecção , Níquel/química , Neoplasias Ovarianas/sangue , Poliestirenos/síntese química , Espectrometria de Fluorescência/métodos
2.
Macromol Rapid Commun ; 40(14): e1900148, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31070820

RESUMO

Multistep catalytic transformations using incompatible catalysts (Wolf-Lamb-type) in a one-pot reaction cascade require site isolation of different catalysts by compartmentalization. In this work, the use of different electrospun catalytic membranes in a modular way as individual compartments is shown for one-pot Wolf-Lamb-type reaction cascades. The data are presented for one-pot cascade reaction sequences catalyzed by acidic and basic membranes made by electrospinning polymeric acid (poly(styrene-co-styrene sulfonic acid-co-4-methacryloyl-oxybenzophen)) and basic (poly(styrene-co-4-vinylpyridine-co-4-methacryloyl-oxybenzophen)) catalysts, respectively. The two-step, one-pot system used is the acidic catalyzed deacetylation of dimethoxybenzylacetale to benzaldehyde, which reacts with ethyl cyanoformate to result in a high yield of product (over 90%) under base-catalyzed conditions. The reaction kinetics are further monitored and evaluated by using differential equations, showing the necessity of a parameter Δt to represent a retarded start for the second reaction step. The concept provides an easy and upscalable approach for use in Wolf-Lamb-type systems.


Assuntos
Catálise , Polímeros/química , Poliestirenos/química , Membranas/química , Metacrilatos/química , Polímeros/síntese química , Poliestirenos/síntese química , Piridinas/síntese química , Piridinas/química , Ácidos Sulfônicos/química
3.
Nat Chem ; 11(6): 578-586, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30988414

RESUMO

Polymerization reactions conducted inside cells must be compatible with the complex intracellular environment, which contains numerous molecules and functional groups that could potentially prevent or quench polymerization reactions. Here we report a strategy for directly synthesizing unnatural polymers in cells through free radical photopolymerization using a number of biocompatible acrylic and methacrylic monomers. This offers a platform to manipulate, track and control cellular behaviour by the in cellulo generation of macromolecules that have the ability to alter cellular motility, label cells by the generation of fluorescent polymers for long-term tracking studies, as well as generate a variety of nanostructures within cells. It is remarkable that free radical polymerization chemistry can take place within such complex cellular environments. This demonstration opens up a multitude of new possibilities for how chemists can modulate cellular function and behaviour and for understanding cellular behaviour in response to the generation of free radicals.


Assuntos
Radicais Livres/química , Polimerização/efeitos da radiação , Ácidos Polimetacrílicos/síntese química , Poliestirenos/síntese química , Acrilatos/química , Acrilatos/efeitos da radiação , Acrilatos/toxicidade , Citoesqueleto de Actina/efeitos dos fármacos , Compostos de Anilina/química , Compostos de Anilina/efeitos da radiação , Compostos de Anilina/toxicidade , Movimento Celular/efeitos dos fármacos , Fluorescência , Células HeLa , Humanos , Metacrilatos/química , Metacrilatos/efeitos da radiação , Metacrilatos/toxicidade , Propano/análogos & derivados , Propano/química , Propano/efeitos da radiação , Fase S/efeitos dos fármacos , Estirenos/química , Estirenos/efeitos da radiação , Estirenos/toxicidade , Raios Ultravioleta , Compostos de Vinila/química , Compostos de Vinila/efeitos da radiação , Compostos de Vinila/toxicidade
4.
Mater Sci Eng C Mater Biol Appl ; 99: 460-467, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30889720

RESUMO

The application range of hydrogels can be greatly widened by improving their mechanical properties. It is still a great challenge to develop hydrogels with good mechanical properties, reliable self-healing properties and remolding ability at the same time. Inspired by biological soft tissue with excellent mechanical properties and self-healing properties, here, a facile method to fabricate poly (styrene-acrylic acid) (P(S-AA)) core-shell nanoparticles with plenty of carboxyl groups on their surface, and their enhancement to hydrophobic association hydrogels was reported. Under stress, the dynamic physical bonds including hydrogen bonding between polymer chains and P(S-AA) core-shell nanoparticles (NPs), and entanglement of hydrophobic chains were destroyed to effectively dissipate energy, and uniform hydrogel network leads to smooth stress-transfer, which makes the core-shell nanoparticles composite hydrophobic association hydrogels (MHA gels) excellent mechanical properties, such as excellent mechanical properties, toughness and ductility, and good self-healing properties as well. These features make the MHA gels have great potential in biomedical applications such as tissue engineering, articular cartilage and artificial skin.


Assuntos
Hidrogéis/química , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Polímeros/química , Acrilatos/síntese química , Acrilatos/química , Elasticidade , Nanopartículas/ultraestrutura , Poliestirenos/síntese química , Poliestirenos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à Tração
5.
Chem Phys Lipids ; 220: 6-13, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30796886

RESUMO

Spectroscopic studies of membrane proteins (MPs) are challenging due to difficulties in preparing homogenous and functional lipid membrane mimetic systems into which membrane proteins can properly fold and function. It has recently been shown that styrene-maleic acid (SMA) copolymers act as a macromolecular surfactant and therefore facilitate the formation of disk-shaped lipid bilayer nanoparticles (styrene-maleic acid copolymer-lipid nanoparticles (SMALPs)) that retain structural characteristics of native lipid membranes. We have previously reported controlled synthesis of SMA block copolymers using reversible addition-fragmentation chain transfer (RAFT) polymerization, and that alteration of the weight ratio of styrene to maleic acid affects nanoparticle size. RAFT-synthesis offers superior control over SMA polymer architecture compared to conventional radical polymerization techniques used for commercially available SMA. However, the interactions between the lipid bilayer and the solubilized RAFT-synthesized SMA polymer are currently not fully understood. In this study, EPR spectroscopy was used to detect the perturbation on the acyl chain upon introduction of the RAFT-synthesized SMA polymer by attaching PC-based nitroxide spin labels to the 5th, 12th, and 16th positions along the acyl chain of the lipid bilayer. EPR spectra showed high rigidity at the 12th position compared to the other two regions, displaying similar qualities to commercially available polymers synthesized via conventional methods. In addition, central EPR linewidths and correlation time data were obtained that are consistent with previous findings.


Assuntos
Lipídeos/química , Maleatos/química , Nanopartículas/química , Poliestirenos/química , Espectroscopia de Ressonância de Spin Eletrônica , Hidrólise , Maleatos/síntese química , Estrutura Molecular , Tamanho da Partícula , Poliestirenos/síntese química
6.
Colloids Surf B Biointerfaces ; 176: 325-333, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30641304

RESUMO

The diblock copolymer polystyrene-block-poly(N-methyl 4-vinylpyridine iodide) (PS-b-P4VPQ) with the molecular weight of PS 3.5 × 103 g/mol and P4VPQ 11.6 × 103 g/mol forms core-shell polymer micelles in aqueous solution. The cationic brush shell of the polymer micelle can be used to accommodate hydrophilic drugs and biomolecules, such as DNA, for biomedical applications. It is essential to understand how biomolecules are adsorbed within the brush layer. Here we investigated the interaction of the cationic brush of the polymer micelle with DNA by small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). It is found when adding only relatively small amounts of on average 30 base pairs (bp) DNA, at 19.6 and 39.2 µM for 0.1 mM PS-b-P4VPQ, most of the polymer micelle/DNA complexes remain well dispersed. The brush layer of the polymer micelles are slightly swelled due to the adsorption of DNA within the brush layer. When the DNA concentration is increased to 58.8 µM or higher, the polymer micelle/DNA complexes form closely packed agglomerates. At high DNA concentrations, some adsorbed DNA will start to build up at the edge or surface of the brush layer which could induce aggregation of the polymer micelle/DNA complexes. This means that it is possible to prepare mostly dispersed polymer/DNA complexes by keeping the DNA concentration below the aggregation concentration. The well dispersed polymer micelle/DNA complexes are advantageous for many DNA related biomedical applications.


Assuntos
DNA/química , Micelas , Poliestirenos/química , Compostos de Piridínio/química , Adsorção , Cátions , Poliestirenos/síntese química , Compostos de Piridínio/síntese química , Espalhamento a Baixo Ângulo , Difração de Raios X
7.
Carbohydr Polym ; 205: 89-97, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30446153

RESUMO

Heparin, a highly sulfated linear polysaccharide, with anticoagulation function and blood compatibility is widely used as a biomaterials in medical application, but the most importance of heparin is its structure function as the macromolecular space arm. In this study, heparin as a spacer was covalently immobilized on the chloromethylated polystyrene microspheres (Ps) and then connected with l-phenylalanine forming the Ps-Hep-Phe structure, which was developed for endotoxin adsorption in hemoperfusion. The grafting density of heparin reach the maximum when the initial concentration of heparin solution was 5 mg/mL. The adsorbents with the heparin as a spacer showed the prolonged clotting times, low protein adsorption, and reduced the hemolysis rate, indicating that heparin-modified adsorbents have great blood compatibility. The adsorption capacity of Ps-Hep-Phe for endotoxin was 25.15 EU/g in dynamic adsorption, higher than that of Ps. Therefore, this study imply that heparin would be promising for modification of adsorbents in hemoperfusion.


Assuntos
Materiais Biocompatíveis/química , Heparina/química , Microesferas , Adsorção , Adulto , Materiais Biocompatíveis/síntese química , Coagulação Sanguínea/efeitos dos fármacos , Proteínas Sanguíneas/química , Endotoxinas/química , Hemólise/efeitos dos fármacos , Hemoperfusão , Heparina/síntese química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Masculino , Tempo de Tromboplastina Parcial , Fenilalanina/análogos & derivados , Fenilalanina/síntese química , Ativação Plaquetária/efeitos dos fármacos , Poliestirenos/síntese química , Poliestirenos/química , Tempo de Trombina
8.
Talanta ; 193: 184-191, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30368289

RESUMO

Diclofenac (DCF) is among the pharmaceutical compounds of concern based on its nocuousness in environment. In this work, a novel electrochemiluminescent (ECL) immunosensor for detecting DCF was constructed using poly(etherimide)-poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate) functionalized graphene oxide and CdSe@CdS quantum dots (QDs-PEI-GO/PEDOT) as bioreceptor for conjugating DCF antibody to magnify signal. It is worth noting that this is the first time GO/PEDOT has been applied to ECL sensor field. Compared with GO, GO/PEDOT exhibited a higher conductivity and more stable chemical property, indicating that the proposed immunosensor would possess stronger and more stable luminescence performance. In addition, the electrode was modified with gold nanorods (AuNRs) which increase the load capacity of DCF coating antigen through Au-N bond. Competitive immunoassay method was chosen for structuring immunosensor where polyclonal antibody (pAb) against DCF exhibited high-affinity recognition of DCF, which greatly improved the sensitively and selectivity of sensor. Consequently, the proposed immunosensor gratified in DCF detection with low detection limit (LODs) of 0.33 pg mL-1 (S/N = 3), and displayed high stability and sensitivity, which initiated a new route for DCF determining.


Assuntos
Diclofenaco/análise , Ouro/química , Grafite/química , Imunoensaio/métodos , Nanotubos/química , Animais , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Diclofenaco/imunologia , Técnicas Eletroquímicas/métodos , Limite de Detecção , Medições Luminescentes/métodos , Nanocompostos/química , Óxidos/química , Polímeros/síntese química , Polímeros/química , Poliestirenos/síntese química , Poliestirenos/química , Pontos Quânticos/química , Coelhos , Reprodutibilidade dos Testes , Tiofenos/síntese química , Tiofenos/química , Águas Residuárias/análise
9.
Macromol Rapid Commun ; 40(2): e1800402, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30199116

RESUMO

RAFT-mediated free-radical emulsion polymerization is successfully used to synthesize polystyrene nanofibers using triblock amphiphilic macro-RAFT copolymers as stabilizers. The polymerization is under RAFT control, producing various morphologies from spherical particles, nanofibers, nanoplatelets, and polymer vesicles. Optimum conditions are established for the synthesis of predominantly negatively charged polymer nanofibers. Superparamagnetic iron oxide nanoparticles (SPION)-decorated nanofibers are formed by simple mixing of the SPIONs with the fibers at an appropriate pH. The composite material has been found to be superparamagnetic and could be aligned under a magnetic field.


Assuntos
Emulsões/química , Compostos Férricos/química , Radicais Livres/química , Nanopartículas de Magnetita/química , Nanofibras/química , Polimerização , Acrilatos/química , Técnicas de Química Sintética/métodos , Concentração de Íons de Hidrogênio , Nanopartículas de Magnetita/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Modelos Químicos , Estrutura Molecular , Nanofibras/ultraestrutura , Poliestirenos/síntese química , Poliestirenos/química , Estireno/química
10.
Macromol Rapid Commun ; 40(2): e1800140, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29687509

RESUMO

A versatile method for synthesis of block copolymer nanoassemblies via initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) dispersion polymerization in a low molecular weight poly(ethylene glycol) (PEG) is discussed. This ICAR ATRP dispersion polymerization uses a low concentration of CuBr2 catalyst, which is stable under atmospheric conditions and is soluble in most polar solvents and employs a polymerization medium of viscous and nonvolatile PEG. Through this ICAR ATRP dispersion polymerization, various block copolymer nanoassemblies, including poly(ethylene glycol)-block-polystyrene, poly(ethylene glycol)-block-poly(methyl methacrylate), and poly(2-hydroxypropyl methacrylate)-block-poly(methyl methacrylate), have been synthesized. The parameters affecting the size and morphology of the block copolymer nanoassemblies are briefly discussed.


Assuntos
Cobre/química , Nanoestruturas/química , Polietilenoglicóis/química , Polimerização , Polímeros/química , Catálise , Técnicas de Química Sintética/métodos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Modelos Químicos , Estrutura Molecular , Peso Molecular , Nanoestruturas/ultraestrutura , Polietilenoglicóis/síntese química , Polímeros/síntese química , Ácidos Polimetacrílicos/síntese química , Ácidos Polimetacrílicos/química , Poliestirenos/síntese química , Poliestirenos/química , Solventes/química
11.
Macromol Rapid Commun ; 40(5): e1800217, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30033548

RESUMO

In this work, an efficient strategy is designed for the precise synthesis of novel Janus star-like copolymer (polystyrene)8 -b-(poly(l-lactide))8 , (PLLA)8 -b-(PS)8 , consisting of two types of chemically distinct polymer arms, PS and PLLA, in an asymmetric structure. During the synthesis, PLLA hemisphere carrying protected hydroxyl groups at the focal point was first synthesized via a combined reactions of esterification, light-induced "Click" chemistry, and ring opening polymerization (ROP) using a specially designed dendron as initiator. After removing the protecting moiety, the terminal hydroxyl groups on the dendron segment is increased fourfold and further modified into bromopropionate-based macroinitiator through a two-step end group transformation reaction, followed by atom transfer radical polymerization (ATRP) of styrene to obtain the desired (PLLA)8 -b-(PS)8 Janus star-like copolymer. The versatility and efficiency of the designed synthetic strategy are demonstrated by the well-defined molecular characteristics and high yields of the targeted product. In addition to the controlled degradation behavior of the PLLA segments, the remaining bromide groups located at the distal end of PS arms could allow for further fabrication of diverse building blocks through consecutive ATRP of various monomers. This work signifies the first time for facile and precise synthesis of Janus star-like copolymer with unique biphasic structure and function control.


Assuntos
Poliésteres/síntese química , Poliestirenos/síntese química , Varredura Diferencial de Calorimetria , Poliésteres/química , Poliestirenos/química , Difração de Raios X
12.
Int J Nanomedicine ; 13: 7771-7787, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30538458

RESUMO

Purpose: Anticancer drug delivery systems are often limited by hurdles, such as off-target distribution, slow cellular internalization, limited lysosomal escape, and drug resistance. To overcome these limitations, we have developed a stable nitric oxide (NO)-releasing nanoparticle (polystyrene-maleic acid [SMA]-tert-dodecane S-nitrosothiol [tDodSNO]) with the aim of enhancing the anticancer properties of doxorubicin (Dox) and a Dox-loaded nanoparticle (SMA-Dox) carrier. Materials and methods: Effects of SMA-tDodSNO and/or in combination with Dox or SMA-Dox on cell viability, apoptosis, mitochondrial membrane potential, lysosomal membrane permeability, tumor tissue, and tumor growth were studied using in vitro and in vivo model of triple-negative breast cancer (TNBC). In addition, the concentrations of SMA-Dox and Dox in combination with SMA-tDodSNO were measured in cells and tumor tissues. Results: Combination of SMA-tDodSNO and Dox synergistically decreased cell viability and induced apoptosis in 4T1 (TNBC cells). Incubation of 4T1 cells with SMA-tDodSNO (40 µM) significantly enhanced the cellular uptake of SMA-Dox and increased Dox concentration in the cells resulting in a twofold increase (P<0.001). Lysosomal membrane integrity, evaluated by acridine orange (AO) staining, was impaired by 40 µM SMA-tDodSNO (P<0.05 vs control) and when combined with SMA-Dox, this effect was significantly potentiated (P<0.001 vs SMA-Dox). Subcutaneous administration of SMA-tDodSNO (1 mg/kg) to xenografted mice bearing 4T1 cells showed that SMA-tDodSNO alone caused a twofold decrease in the tumor size compared to the control group. SMA-tDodSNO in combination with SMA-Dox resulted in a statistically significant 4.7-fold reduction in the tumor volume (P<0.001 vs control), without causing significant toxicity as monitored through body weight loss. Conclusion: Taken together, these results suggest that SMA-tDodSNO can be used as a successful strategy to increase the efficacy of Dox and SMA-Dox in a model of TNBC.


Assuntos
Antineoplásicos/farmacologia , Doxorrubicina/farmacologia , Liberação Controlada de Fármacos , Nanopartículas/química , Óxido Nítrico/farmacologia , Animais , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/administração & dosagem , Doxorrubicina/uso terapêutico , Endocitose , Feminino , Humanos , Injeções Subcutâneas , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Maleatos/síntese química , Maleatos/química , Camundongos Endogâmicos BALB C , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Permeabilidade , Poliestirenos/síntese química , Poliestirenos/química , S-Nitrosotióis/síntese química , S-Nitrosotióis/química , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/patologia
13.
Langmuir ; 34(39): 11814-11821, 2018 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-30183312

RESUMO

Polydopamine (PDA) is of interest as a mimetic material of melanin to produce structural color materials. Herein, to investigate the influence of the material composition of the artificial melanin particles on structural color, we demonstrated the preparation of core-shell particles by polymerization of norepinephrine or 3,4-dihydroxyphenylalanine, which are melanin precursors similar to dopamine, in the presence of polystyrene particles. It was revealed that the arrays of the prepared particles produce high-visibility structural color because of absorption of scattering light. Although poly(3,4-dihydroxyphenylalanine) showed the same tendency as PDA which was previous studied, polynorepinephrine can easily produce a smooth and thick shell layer compared with that of PDA, and pellets consisting of the particles showed angle-dependent structural color. Therefore, the artificial melanin particles that produce angle-dependent structural color became stable than ever before. These results indicated that material compositions of artificial melanin particles have influence on structural color, and an important finding for application as a coloring material was obtained.


Assuntos
Materiais Biomiméticos/química , Di-Hidroxifenilalanina/análogos & derivados , Indóis/química , Melaninas/química , Norepinefrina/química , Polímeros/química , Materiais Biomiméticos/síntese química , Cor , Di-Hidroxifenilalanina/síntese química , Di-Hidroxifenilalanina/química , Indóis/síntese química , Polimerização , Polímeros/síntese química , Poliestirenos/síntese química , Poliestirenos/química , Propriedades de Superfície
14.
Langmuir ; 34(37): 11042-11048, 2018 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-30124299

RESUMO

DNA-mediated self-assembly of colloidal particles is one of the most promising approaches for constructing colloidal superstructures. For nanophotonic materials and devices, DNA-functionalized colloids with diameters of around 100 nm are essential building blocks. Here, we demonstrate a strategy for synthesizing DNA-functionalized polymer nanoparticles (DNA-polyNPs) in the size range of 55-150 nm using block copolymer micelles as a template. Diblock copolymers of polystyrene- b-poly(ethylene oxide) with an azide end group (PS- b-PEO-N3) are first formed into spherical micelles. Then, the micelle cores are swollen with the styrene monomer and polymerized, thus producing PS NPs with PEO brushes and azide functional end groups. DNA strands are conjugated onto the ends of the PEO brushes through a strain-promoted alkyne-azide cycloaddition reaction, resulting in a DNA density of more than one DNA strand per 12.6 nm2 for 70 nm particles. The DNA-polyNPs with complementary sequences enable the formation of CsCl-type colloidal superstructure by DNA binding.


Assuntos
DNA/química , Micelas , Nanopartículas/química , Polietilenoglicóis/química , Poliestirenos/química , Alquinos/química , Azidas/química , Coloides/química , Reação de Cicloadição , Tamanho da Partícula , Polimerização , Poliestirenos/síntese química
15.
Anal Chim Acta ; 1030: 194-201, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-30032769

RESUMO

Mono-dispersed polystyrene-based microspheres with diameters about 1 µm encapsulating rhodamine moieties as oxygen insensitive internal reference probes and platinum octaethylporphyrin units as oxygen sensitive probes were synthesized as new ratiometric oxygen sensors (Rhod-PtOEP-PS). The dual luminophors of rhodamines and platinum porphyrin moieties exhibited emissions maxima at 585 nm and 644 nm, respectively. The microspheres showed good oxygen sensing properties in different oxygen partial pressures (pO2) and dissolved oxygen (DO) concentrations. It was found the oxygen probes and reference probes in microspheres showed higher photo-stability than their corresponding free fluorophores in solution. The microspheres also showed good sensitivity for air-pressure and cellular oxygen in cell culture medium. These microspheres were used to detect DOs in a few kinds of liquids including some daily drinks and it was found the measured errors were within positive/negative 11% as compared with the measured results using traditional oxygen electrodes.


Assuntos
Microesferas , Oxigênio/análise , Poliestirenos/química , Estrutura Molecular , Tamanho da Partícula , Poliestirenos/síntese química , Propriedades de Superfície
16.
Chem Commun (Camb) ; 54(66): 9119-9122, 2018 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-29947376

RESUMO

On-demand initiation of dual- and multi-component microreactions inside liquid marbles (LMs) was developed by coalescing contacting patchy LMs containing separate reagents through CO2-induced wetting transition of the interface between the LMs.


Assuntos
Dióxido de Carbono/química , Ácidos Polimetacrílicos/química , Poliestirenos/química , Bromo/química , Ferricianetos/química , Interações Hidrofóbicas e Hidrofílicas , Iodo/química , Tamanho da Partícula , Fenol/química , Ácidos Polimetacrílicos/síntese química , Poliestirenos/síntese química , Permanganato de Potássio/química , Amido/química , Sulfatos/química , Molhabilidade
17.
Macromol Rapid Commun ; 39(9): e1800043, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29578265

RESUMO

The synthesis and self-assembly in thin-film configuration of linear ABC triblock terpolymer chains consisting of polystyrene (PS), poly(2-vinylpyridine) (P2VP), and polyisoprene (PI) are described. For that purpose, a hydroxyl-terminated PS-b-P2VP (45 kg mol-1 ) building block and a carboxyl-terminated PI (9 kg mol-1 ) are first separately prepared by anionic polymerization, and then are coupled via a Steglich esterification reaction. This quantitative and metal-free catalyst synthesis route reveals to be very interesting since functionalization and purification steps are straightforward, and well-defined terpolymers are produced. A solvent vapor annealing (SVA) process is used to promote the self-assembly of frustrated PS-b-P2VP-b-PI chains into a thin-film core-shell double gyroid (Q230 , space group: Ia3¯d) structure. As terraces are formed within PS-b-P2VP-b-PI thin films during the SVA process under a CHCl3 vapor, different plane orientations of the Q230 structure ((211), (110), (111), and (100)) are observed at the polymer-air interface depending on the film thickness.


Assuntos
Butadienos/química , Hemiterpenos/química , Nanoestruturas/química , Pentanos/química , Poliestirenos/química , Polivinil/química , Butadienos/síntese química , Hemiterpenos/síntese química , Tamanho da Partícula , Pentanos/síntese química , Polímeros/síntese química , Polímeros/química , Poliestirenos/síntese química , Polivinil/síntese química
18.
Anal Chim Acta ; 1014: 1-9, 2018 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-29523246

RESUMO

Parabens are used as antimicrobial preservatives in food, cosmetic products and pharmaceuticals regardless of their endocrine disrupting effect. In this study, highly selective molecular imprinted polymers (MIPs) were synthesized in submicron-sizes and converted to an SPME fiber coating through electrospinning process in order to determine parabens in water samples. Conversion of MIP to a fiber is achieved via creation of spacial knitting around MIP by polystyrene. The selectivity and extraction ability of the fibers were compared with the commercial fibers and the corresponding non-imprinted polymer (NIP) coated fiber. The coated fiber showed better extraction ability among them. Also, the results revealed that the fiber has better selectivity for benzyl paraben and the other structurally-related compounds, such as methyl and propyl paraben. Extraction efficiency of prepared fibers for three parabens has been tested by spiking bottled, tap and sea water samples. The recoveries changed between 92.2 ±â€¯0.8 and 99.8 ±â€¯0.1 for three different water types. This method could be used for selective and sensitive determination of parabens in aqueous samples.


Assuntos
Acrilatos/química , Impressão Molecular , Parabenos/análise , Poliestirenos/química , Adsorção , Microesferas , Poliestirenos/síntese química
19.
Macromol Rapid Commun ; 38(22)2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28980746

RESUMO

Block copolymer (BCP) self-assembly is a versatile technique in the preparation of polymeric aggregates with varieties of morphologies. However, its morphology library is limited. Here, the discovery of pincushion of tubules is reported for the first time, via BCP self-assembly of poly(4-vinylpyridine)-b-polystyrene (P4VP-b-PS) with very high molecular weight (500 kDa) and asymmetry (2 mol% P4VP). The investigation confirms the importance of core-forming block length on morphology control of BCP self-assemblies, especially with respect to tubular structures. The morphology landscape of tubular structures is successfully established, where dumbbell of tubule, tubule, loose clew of tubules, tight clew of tubules, and pincushion of tubules can be prepared by adjusting the core-forming block length. This work therefore expands the structure library of BCP self-assemblies and opens up a new avenue for the further applications of these tubular materials.


Assuntos
Poliestirenos/química , Polivinil/química , Microscopia Eletrônica de Transmissão , Peso Molecular , Nanoestruturas/química , Poliestirenos/síntese química , Polivinil/síntese química
20.
Macromol Rapid Commun ; 38(19)2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28804973

RESUMO

The preparation of well-defined block copolymers using controlled radical polymerization depends on the proper order of monomer addition. The reversed order of monomer addition results in a mixture of block copolymer and homopolymer and thus has typically been avoided. In this paper, the low blocking efficiency of reversed monomer addition order is utilized in combination with surface initiated reversible addition-fragmentation chain-transfer polymerization to establish a facile procedure toward mixed polymer brush grafted nanoparticles SiO2 -g-(PS (polystyrene), PS-b-PMAA (polymethacrylic acid)). The SiO2 -g-(PS, PS-b-PMAA) nanoparticles are analyzed by gel permeation chromatography deconvolution, and the fraction of each polymer component is calculated. Additionally, the SiO2 -g-(PS, PS-b-PMAA) are amphiphilic in nature and show unique self-assembly behavior in water.


Assuntos
Nanopartículas/química , Polímeros/química , Poliestirenos/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Metacrilatos/síntese química , Metacrilatos/química , Metacrilatos/uso terapêutico , Polimerização , Polímeros/síntese química , Poliestirenos/síntese química , Poliestirenos/uso terapêutico , Dióxido de Silício/síntese química , Dióxido de Silício/química , Dióxido de Silício/uso terapêutico , Propriedades de Superfície , Água/química
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