Dielectric spectroscopy as a probe for the investigation of conformational properties of proteins

Bonincontro, A.; Risuleo, Gianfranco

doi:10.1016/s1386-1425(03)00085-4

Cited by 33 publications

(17 citation statements)

References 44 publications

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“…The option of distinguishing between free and bound water makes these methods attractive to investigate corrosion [18,133], changes in hydration in nanoporous systems [1] or transitions of thermo-responsive polymers [63,118]. Dipole responses in biomaterials include studies covering a broad range of applications [62,89,119] from molecules [11,34,59,130] via cells [84,101,103,132] to tissues [27,104]. In the framework of this book, two examples for application from the biosciences are being presented, both acquired in AC fields.…”

Section: Applicationsmentioning

confidence: 99%

Bioimpedance Spectroscopy

Klösgen

Rümenapp

Gleich

2011

BetaSys

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In the context of biology, electrical phenomena are usually identified with ionic currents through protein channels, for example as they are postulated during nerve signalling (Andersen et al. Prog Neurobiol 88(2):104-113, 2009; Sakmann and Neher Annu Rev Physiol 46:455-472, 1984). However, there are more electrical phenomena that play a significant role in biological systems, namely those arising from polarization effects (Grimnes Bioimpedance and Bioelectricity, 2008; Polk Handbook of Biological Effects of Electromagnetic Fields 1996). Local inhomogeneities in charge distributions give rise to the formation of permanent molecular dipoles as in uncharged molecules such as (hydration) water, or due to the polar groups in proteins and lipid molecules. Non-permanent electrical dipoles can originate from the presence of ions in solution. Structured distributions of counter-ions at all polar interfaces, for example along the surface of proteins and especially along the polar membrane interfaces of cells, cause the formation of Stern and Helmholtz layers. All non-uniform distributions of charges and dipoles initiate and modify internal local electrical fields. Moreover, the application of external fields causes relaxation processes with characteristic contributions to the frequency-dependent complex dielectric constant. These dipolar relaxations were initially described by Debye (

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Section: Applicationsmentioning

confidence: 99%

Bioimpedance Spectroscopy

Klösgen

Rümenapp

Gleich

2011

BetaSys

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“…The enhancement of the real part of permittivity of the composite material at low frequencies and at low temperatures is attributed to the presence of water dipoles polarization present in the pectocellulosic fiber which is absorbed to form a molecular monolayer . These water molecules are related to the hydroxyl groups of cellulose fiber and could not be removed by a simple heat treatment . This water dipole relaxation type was largely studied in several works .…”

Section: Resultsmentioning

confidence: 99%

Influence of two carbon plies on adhesion of unidirectional flax‐fibers reinforced epoxy composites

Karray

Triki²,

Poilâne

et al. 2014

Polymer Composites

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In this work, we undertook a comparative study of the dynamic dielectric analysis of two unidirectional epoxy composites: flax-fiber-reinforced epoxy and flax/carbon-fiber-reinforced epoxy (FCFRE). In both composites, three relaxation processes were identified. The first one is the water dipoles polarization imputed to the presence of polar water molecules in flax fiber. The second relaxation process associated with conductivity occurs as a result of the carriers charges diffusion noted for high temperature above glass transition and low frequencies. As for the third dielectric relaxation associated with the interfacial polarization effect is attributable to the accumulation of charges at the fibers/matrix interface. The presence of two carbon plies in the reinforcement gives rise to two interfacial polarization effects in the FCFRE composite. The analysis of the Maxwell-Wagner-Sillars and the water dipoles polarizations using the Havriliak-Negami model revealed that the presence of two plies of carbon can locally decrease the adhesion of flax fibers in the matrix. This analysis was supported by the thermal properties using a differential scanning calorimety and the mechanical properties using a short beam shear test. POLYM. COMPOS., 37:241-253, 2016.

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“…Various methods such as analytical ultracentrifugation, dielectric dispersion, and transient birefringence have been used to measure the hydrodynamic size of proteins. [29][30][31] Modeled as ellipsoids, a BSA molecule has a size of 4.0 × 4.0 × 14.0 nm with a 0.5 nm uncertainty for each dimension. 30 Using this size of BSA, the surface mass densities were calculated to be 1.9 and 6.8 ng/mm 2 in side-on (long axis parallel to the surface) and end-on (long axis perpendicular to the surface) monolayers, respectively.…”

Section: Oi-rd-based Characterizationmentioning

confidence: 99%

Characterization of Bovine Serum Albumin Blocking Efficiency on Epoxy-Functionalized Substrates for Microarray Applications

Sun

Zhu

2016

SLAS Technology

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Microarrays provide a platform for high-throughput characterization of biomolecular interactions. To increase the sensitivity and specificity of microarrays, surface blocking is required to minimize the nonspecific interactions between analytes and unprinted yet functionalized surfaces. To block amine-or epoxy-functionalized substrates, bovine serum albumin (BSA) is one of the most commonly used blocking reagents because it is cheap and easy to use. Based on standard protocols from microarray manufactories, a BSA concentration of 1% (10 mg/mL or 200 μM) and reaction time of at least 30 min are required to efficiently block epoxy-coated slides. In this paper, we used both fluorescent and label-free methods to characterize the BSA blocking efficiency on epoxy-functionalized substrates. The blocking efficiency of BSA was characterized using a fluorescent scanner and a label-free oblique-incidence reflectivity difference (OI-RD) microscope. We found that (1) a BSA concentration of 0.05% (0.5 mg/mL or 10 μM) could give a blocking efficiency of 98%, and (2) the BSA blocking step took only about 5 min to be complete. Also, from real-time and in situ measurements, we were able to calculate the conformational properties (thickness, mass density, and number density) of BSA molecules deposited on the epoxy surface.

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Dielectric spectroscopy as a probe for the investigation of conformational properties of proteins

Cited by 33 publications

References 44 publications

Bioimpedance Spectroscopy

Bioimpedance Spectroscopy

Influence of two carbon plies on adhesion of unidirectional flax‐fibers reinforced epoxy composites

Characterization of Bovine Serum Albumin Blocking Efficiency on Epoxy-Functionalized Substrates for Microarray Applications

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