Counterions in layer-by-layer films—Influence of the drying process

Lourenço, João P.; Ribeiro, Paulo A.; Rego, A.M. Botelho do; Raposo, Maria

doi:10.1016/j.jcis.2007.04.040

Cited by 47 publications

(45 citation statements)

References 49 publications

(66 reference statements)

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“…A methodology to accomplish this is to assemble, from a liquid/solid interface, biological molecules such as lipids, DNA, proteins and enzymes onto solid substrates covered with a soft cushion of adsorbed polyelectrolytes having a high water content [10,11]. A simple and versatile method for producing these architectures is the sequential build up of layers of functional materials by the layer-by-layer (LBL) technique [12,13].…”

Section: A C C E P T E D Article In Pressmentioning

confidence: 99%

“…However, the characterization of the UV radiation effect (140 nm) on DNA molecules in vacuum as performed in this work is of importance for comparison of the effect of UV radiation on DNA molecules surrounded by water molecules to infer its real contribution for the DNA damage. Actually (data not reported in this article) the amount of water molecules surrounding the DNA molecules is being controlled [19] taking into account the achievements of Lourenço et al [10,11] …”

Section: A C C E P T E D Article In Pressmentioning

confidence: 99%

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UV degradation of deoxyribonucleic acid

Gomes

Ribeiro

Shaw

et al. 2009

Polymer Degradation and Stability

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Section: A C C E P T E D Article In Pressmentioning

confidence: 99%

Section: A C C E P T E D Article In Pressmentioning

confidence: 99%

UV degradation of deoxyribonucleic acid

Gomes

Ribeiro

Shaw

et al. 2009

Polymer Degradation and Stability

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“…Além disso, permite a manutenção de água entre as camadas adsorvidas, tornando o processo de fabricação mais favorável e brando as biomoléculas. 38 A técnica LB foi desenvolvida por Irving Langmuir e sua assistente Katherine Blodgett e requer um equipamento denominado Cuba de Langmuir. Neste equipamento, moléculas anfifílicas (substâncias que possuem uma estrutura química característica contendo uma região hidrofílica -região polar e outra hidrofóbica -região apolar), são espalhadas em uma interface ar-água de tal forma que a região polar das moléculas interaja com a água e a apolar fique voltada para o ar.…”

Section: Métodos De Fabricação De Biossensoresunclassified

Liposome-Encapsulated Biomolecules: Application in Enzymatic Biosensors and Immunosensors

Graça¹,

Ferreira²

2015

Revista Virtual De Química

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Abstract:Biomolecules are largely used in the development of biosensors since they present high specificity and selectivity with the analyte. However, these properties can be affected during and after immobilization on the transducer surface, impairing the good functioning of the device. However, the construction of a more accurate and stable device requires that these characteristics are retained after immobilization. In this case, biomolecules encapsulation in liposomes has helped to preserve the structure and activity of molecules immobilized on substrate. Therefore, this article shows the importance of combining the adsorption technique with the encapsulation of biomolecules in liposomes to improve the operation of these devices. Keywords:Biosensors; Biomolecules; Layer-by-Layer; Langmuir-Blodgett; liposome. ResumoAs biomoléculas são amplamente utilizadas no desenvolvimento de biossensores, pois apresentam alta especificidade e seletividade com o analito. No entanto, a construção de dispositivos mais precisos e estáveis requer que estas propriedades sejam mantidas após a imobilização, neste sentido a encapsulação de biomoléculas em lipossomos tem ajudado a preservar a estrutura e atividade das biomoléculas que são imobilizadas. Portanto, o presente artigo mostra a importância da combinação da técnica de adsorção com a encapsulação das biomoléculas em lipossomos para melhorar o funcionamento destes dispositivos.

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“…The potential energy difference due to the POMA layer should be at most 0.1 eV for a 100 nm-PPV film, considering a parallel-plate capacitor model and a surface charge density of 5 C/m 2 estimated from XPS measurements that demonstrated the existence of excess surface charge. 20,21 Each PPV segment is under a potential energy difference of 0.6 eV, estimated by taking a dielectric constant of 3 for a conjugated polymer (e ¼ 3e 0 ) 22 and a typical width of a segment of 5 Å . This energy difference of 0.6 eV is consistent with the experimentally obtained activation energy (0.651 eV) for a full rotation of the phenyl ring of crystalline PPV measured with nuclear magnetic resonance (NMR).…”

Section: B Theoretical Modelmentioning

confidence: 99%

Structure control of poly(p-phenylene vinylene) in layer-by-layer films by deposition on a charged poly(o-methoxyaniline) cushion

Marletta

Silva

Piovesan

et al. 2013

Journal of Applied Physics

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In this paper, we demonstrate that the intrinsic electric field created by a poly(o-methoxyaniline) (POMA) cushion layer hinders the changes in molecular conformation of poly(p-phenylenevinylene) (PPV) in layer-by-layer with dodecylbenzene sulfonic acid (DBS). This was modeled with density functional theory (DFT) calculations where an energy barrier hampered molecular movements of PPV segments when they were subjected to an electric field comparable to that caused by a charged POMA layer. With restricted changes in molecular conformation, the PPV film exhibited Franck-Condon transitions and the photoexcitation spectra resembled the absorption spectra, in contrast to PPV/DBS films deposited directly on glass, with no POMA cushion. Other effects from the POMA cushion were the reduced number of structural defects, confirmed with Raman spectroscopy, and an enhanced PPV emission at high temperatures (300 K) in comparison with the films on bare glass. The positive effects from the POMA cushion may be exploited for enhanced opto-electronic devices, especially as the intrinsic electric field may assist in separating photoexcited electron-hole pairs in photovoltaic devices.

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Counterions in layer-by-layer films—Influence of the drying process

Cited by 47 publications

References 49 publications

UV degradation of deoxyribonucleic acid

UV degradation of deoxyribonucleic acid

Liposome-Encapsulated Biomolecules: Application in Enzymatic Biosensors and Immunosensors

Structure control of poly(p-phenylene vinylene) in layer-by-layer films by deposition on a charged poly(o-methoxyaniline) cushion

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