Poly(ethylene oxide)poly(propylene oxide)poly(ethylene oxide) block copolymer surfactants in aqueous solutions and at interfaces: thermodynamics, structure, dynamics, and modeling

Alexandridis, Paschalis; Hatton, T. Alan

doi:10.1016/0927-7757(94)03028-x

Cited by 1,742 publications

(1,596 citation statements)

References 129 publications

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“…The present review describes the effect of mixed PEG on the non-biofouling character and also hybrid construction of a PEG/biopolymer mixture on substrate surfaces for versatile applications. Because many excellent reviews on PEG surface coating have been previously published, [15][16][17][18][19][20][21][22][23][24][25][26][27][28] this review mainly introduces our work. BACKGROUND PEG has long been manufactured industrially and utilized in many applications such as nonionic surfactants, lubricants, an intermediate for urethane composition, adhesives and cosmetics.…”

Section: Introductionmentioning

confidence: 99%

“…This is especially true regarding the versatile techniques for surface coating using PEG that have been developed since the 1980s to improve blood and bio-compatibility. Figure 1 summarizes several methods for the immobilization of PEG on substrate surfaces: PEG gels, 19,20,36 the physical and chemical immobilization of PEG 13,21,37 (so-called grafting-to method), the adsorption of block [22][23][24][25][26][27]38 and graft 27,28,39,40 copolymers, polymerization from the surface 41 (the so-called grafting-from method), the immobilization of star-shape polymers and micelles, [42][43][44] and other methods.…”

Section: Introductionmentioning

confidence: 99%

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Construction of a densely poly(ethylene glycol)-chain-tethered surface and its performance

Nagasaki

2011

Polym J

109

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Non-biofouling surfaces constitute one of the most important subjects in sensitively and selectively detecting biomolecular events. Poly(ethylene glycol) (PEG) chains tethered on substrate surfaces are well known to reduce non-biofouling characteristics. Protein adsorption onto a PEG-chain-tethered surface is strongly influenced by the density of the PEG chain and is almost completely suppressed by the successive treatment of longer PEG chains (5 kDa) followed by the treatment of PEG (2 kDa; mixed-PEG-chain-tethered surface) because of a significant increase in PEG chain density. To modify versatile substrate surface, PEG possessing pentaethylenehexamine at one end (N6-PEG) was prepared via a reductive amination reaction of aldehyde-ended PEG with pentaethylenehexamine. Using N6-PEG, antibody/PEG co-immobilization was conducted on a substrate possessing active ester groups. After the antibody was immobilized on the surface, PEG tethered chains were constructed surrounding the immobilized antibody. It is interesting to note that the PEG-chain-tethered functions not only as a non-fouling agent but also improves immune response. The hybrid surface was also applied to oligo DNA immobilization. The oligo DNA/PEG hybrid surface improved hybridization, retaining its non-fouling ability. Densely packed PEG tethered chains surrounding antibodies and/or oligo DNA improved their orientation on the surface. Thus, this material is promising as a high-performance biointerface for versatile applications. Keywords: antibody; biosensing; DNA; end-functionalized poly(ethylene glycol); enzyme-linked immunosorbent assay; hybrid biointerface; soft interface INTRODUCTION Specific biorecognition on substrate surfaces has long been utilized in many applications such as biosensing, 1 immunodiagnostics, 2 enzyme immunoassay, 3 western blotting 4 and protein microarrays. 5 Important factors for the improvement in specific biorecognition on surfaces are the suppression of nonspecific biofouling and the suitable orientation of immobilized biomolecules. The former decreases nonspecific noise and the background level, and the latter increases the specific recognition level. To improve the non-biofouling character of surfaces, numerous efforts have been undertaken. In general, natural polymers such as albumin, casein and dextran have been used for blocking on substrate surfaces. 6 These treatments work well and suppress protein biofouling extensively. If extremely high performance is required, however, these blocking treatments are not enough. In addition, natural products, especially those derived from animals, may have undesired contents such as bacteria and viruses, which may affect the user. 7 Under these circumstances, synthetic polymers have been recently suggested as suitable surface blocking agents. Numerous types of water-soluble polymers, such as poly(acrylamide), poly(vinyl alcohol), poly(vinyl pyrrolidone) and poly(ethylene glycol) (PEG), have been investigated so far. Recently, new types of synthetic polymers such as poly(methoxy ...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Construction of a densely poly(ethylene glycol)-chain-tethered surface and its performance

Nagasaki

2011

Polym J

109

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“…[13][14][15][16] Linear block copolymers are an attractive class of polymers for these applications due to their relatively simple synthesis, their ability to form micelle structures in aqueous solution, and their wide availability through commercial production. [17][18][19][20][21] One of the most interesting applications in the bioreleaserelated field were found for responsive materials based on the amphiphilic triblock copolymer poly((ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)) (PEO-PPO-PEO) commercially known as Pluronic or Poloxamer. The PEO-PPO-PEO chain can be modified by varying the length of each block so that the final chain exhibits the desired thermoresponsive gelation properties at physiological conditions for injectable delivery.…”

Section: Introductionmentioning

confidence: 99%

“…The PEO-PPO-PEO chain can be modified by varying the length of each block so that the final chain exhibits the desired thermoresponsive gelation properties at physiological conditions for injectable delivery. 17,22 These gels can then dissolve slowly to release polymer micelles loaded with drugs. This base system can then be used as the central building block for further modification by adding various functional groups to both ends of the chain.…”

Section: Introductionmentioning

confidence: 99%

Thermoresponsive Reversible Behavior of Multistimuli Pluronic-Based Pentablock Copolymer at the Air−Water Interface

et al. 2006

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Surface behavior of the pH-and thermoresponsive amphiphilic ABCBA pentablock copolymer has been studied with respect to the environmental conditions. We demonstrate that the pentablock copolymer poly((diethylaminoethyl methacrylate)-b-(ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)-b-(diethylaminoethyl methacrylate)) possesses reversible temperature changes at the air-water interface in a narrow pH range of the water subphase. Significant diversity in the surface morphology of pentablock copolymer monolayers at different pH and temperatures observed were related to the corresponding reorganization of central and terminal blocks. Remarkable reversible variations of the surface pressure observed for the Langmuir monolayers at pH 7.4 in the course of heating and cooling between 27 and 50Â°C is associated with conformational transformations of terminal blocks crossing the phase line in the vicinity of the lower critical solution temperature point. The observed thermoresponsive surface behavior can be exploited for modeling of the corresponding behavior of pentablock copolymers adsorbed onto various biointerfaces for intracellular delivery for deeper understanding of stimuli-responsive transformations relevant to controlled drug and biomolecules release and retention. Surface behavior of the pH-and thermoresponsive amphiphilic ABCBA pentablock copolymer has been studied with respect to the environmental conditions. We demonstrate that the pentablock copolymer poly((diethylaminoethyl methacrylate)-b-(ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)-b-(diethylaminoethyl methacrylate)) possesses reversible temperature changes at the air-water interface in a narrow pH range of the water subphase. Significant diversity in the surface morphology of pentablock copolymer monolayers at different pH and temperatures observed were related to the corresponding reorganization of central and terminal blocks. Remarkable reversible variations of the surface pressure observed for the Langmuir monolayers at pH 7.4 in the course of heating and cooling between 27 and 50°C is associated with conformational transformations of terminal blocks crossing the phase line in the vicinity of the lower critical solution temperature point. The observed thermoresponsive surface behavior can be exploited for modeling of the corresponding behavior of pentablock copolymers adsorbed onto various biointerfaces for intracellular delivery for deeper understanding of stimuli-responsive transformations relevant to controlled drug and biomolecules release and retention.

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“…O número de agregação é em torno de 50, mas é dependente de vários fatores (massa molar, temperatura, solvente, unidades a e b, concentração, etc). A cinética de formação da micela e o equilíbrio de inclusão/exclusão de monômeros são lentos, justificados pelo elevado tamanho das moléculas [16][17][18][19] sendo que, para este caso, é necessário aguardar sua estabilização em solução.…”

Section: Figura 1 Ilustração Do Arranjo De Moléculas De Anfifílicos unclassified

O pKa de indicadores ácido-base e os efeitos coloidais

Previdello¹,

Carvalho²,

Tessaro³

et al. 2006

Quím. Nova

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Recebido em 31/1/05; aceito em 12/8/05; publicado na web em 14/3/06 THE pK a OF ACID-BASE INDICATORS AND THE INFLUENCE OF COLLOIDAL SYSTEMS. An experiment is proposed that can be included in undergraduate courses of chemistry. The subject is the acidity of organic compounds, which are employed as pH indicators, particularly in acid-base titrations. The indicators used are methyl orange, bromophenol blue and bromocresol green in aqueous medium. The influence of colloidal systems on the equilibrium is evaluated by the pK a . The colloids employed are surfactants like sodium dodecyl sulfate, cetyl-trimethylammonium bromide and a polymeric non-ionic F127 (pluronics). The effect of stabilization promoted by the system on the acidic or basic structureof the indicator establishes the action mechanism of the colloid on the pK a values.Keywords: pK a ; acid-base indicator; colloidal systems. INTRODUÇÃONo âmbito universitário, pesquisa científica e ensino são áreas que devem estar em simbiose e, quanto mais próximas, maiores são os benefícios a ambas. Uma das ações nesta linha é apresentar e motivar discussões em salas de aulas, de pesquisas científicas avançadas conectadas aos conteúdos programáticos ministrados nas disciplinas. Em muitos casos, porém, não se tem esta associação devido, principalmente, à complexidade e especificidade da pesquisa, provocando o distanciamento desta em relação ao aluno. Tendo em mente este fato, nosso grupo tem trabalhado no desenvolvimento de práticas laboratoriais para disciplinas experimentais de físico-química, abordando sistemas usados em pesquisas científicas e apresentando-os em experimentos "relativamente" simples, visando correlacionar propriedades físico-químicas com conceitos contidos no programa curricular dos cursos de Química. Dessa forma, de maneira mais motivadora, focada e didática, procura-se clarificar conceitos e propriedades físi-co-químicas desses sistemas apresentando experimentos que possam ser incluídos nas disciplinas dos cursos de graduação. Neste trabalho abordamos temas que despertam o interesse devido à importância científica e no cotidiano/indústria: compostos ácido-base, particularmente, o conceito de pK a e sua determinação; os sistemas coloidais. Mostra-se, aqui, a determinação de pK a e, a partir da comparação dos valores obtidos em água e em sistemas coloidais, avalia-se a modificação micro-local do ambiente e do equilíbrio químico.A classe de compostos investigada, quanto ao pK a , é a de indicadores ácido-base utilizados em determinações de acidez através de curvas de titulação, os quais, em boa parte, propiciaram o desenvolvimento da química analítica quantitativa volumétrica moderna 1 . Estes compostos são moléculas orgânicas cromóforas que absorvem na região do visível (corantes), cuja sensibilidade à concentração de íons H + permite indicar o grau de acidez do ambiente onde estão inseridos. Esta propriedade advém do fato deles próprios serem substâncias ácidas ou básicas fracas e que têm seu sistema cromóforo fortemente influenciado pelo grupamento ...

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Poly(ethylene oxide)poly(propylene oxide)poly(ethylene oxide) block copolymer surfactants in aqueous solutions and at interfaces: thermodynamics, structure, dynamics, and modeling

Cited by 1,742 publications

References 129 publications

Construction of a densely poly(ethylene glycol)-chain-tethered surface and its performance

Construction of a densely poly(ethylene glycol)-chain-tethered surface and its performance

Thermoresponsive Reversible Behavior of Multistimuli Pluronic-Based Pentablock Copolymer at the Air−Water Interface

O pKa de indicadores ácido-base e os efeitos coloidais

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