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Characterization of Biological and Environmental Particles Using Static and Dynamic Light Scattering
Published in Jacques Buffle, Herman P. van Leeuwen, Environmental Particles, 2018
Peter Schurtenberger, Meredith E. Newman
Equation 38 is routinely used to analyze SLS data from suspensions of biological macromolecules, polymers, or colloids. It clearly shows that for polydisperse solutions, static light scattering provides a measurement of average quantities (<M> and <Rg2>) only. Taking into account the proper weighting with Mi and Mi2, respectively, is particularly important when we try to compare light scattering results with those from other types of experiments such as electron microscopy or size exclusion chromatography.
Characterization Techniques
Published in Jagriti Narang, Chandra Shekhar Pundir, Biosensors, 2017
Jagriti Narang, Nitesh Malhotra, Chandra Shekhar Pundir
There are two types of light scattering methods: (i) dynamic and (ii) static. Static light scattering measures time–average intensities, while dynamic light scattering (DLS) measures real-time intensities and thus dynamic properties. The rate at which particles diffuse is related to their size, provided all other parameters are constant [15]. DLS isaccurate, reliable, noninvasive, and consumes very less time in the analysis of nanoparticles. Furthermore, this approach allows the investigation of particles in their own environment [16]. DLS also helps in determining whether the nanoparticles are monodisperse or polydisperse. If the peak is sharp, the particles are monodisperse, but if the peak is broad, the particles are polydisperse.
Scattering from Wormlike Micelles
Published in Raoul Zana, Eric W. Kaler, Giant Micelles, 2007
Jan Skov Pedersen, Luigi Cannavacciuolo, Peter Schurtenberger
Static light scattering data are easily normalized to absolute scale using a solvent such as toluene as a standard. The scattering contrast of an object is expressed in terms of the refractive index increments which can be obtained experimentally using a refractometer. With this, the intensity can be converted so that the forward scattering intensity is directly the weight-average molar mass of the objects in the solution, I(q = 0) = Mw.8 However, this relation is only valid at low concentration, where there are no interparticle interference effects. At higher concentration, the relation becomes: I(q=0)=MwS(0)
Reservoir applicability and flooding effect of amphoteric ion crosslinked polymer solution
Published in Journal of Dispersion Science and Technology, 2021
Jianbing Li, Wenxiang Wu, Liwei Niu, Mingxing Bai, Yue Zhang, Ying Jiang
Viscosity was measured at 45°5 by using an LVDV-II + PRO Buchner viscometer at the shearing speed of 7.35 s−1. The micro-morphology was observed under a JEM-3200FSC freeze etching transmission electron microscope (TEM). The molecular aggregate dimension Dh of each polymer was monitored by a BI-200SM wide-angle dynamic/static light scattering apparatus (Brookhaven Instruments Corp., USA) at the laser wavelength of 532.0 nm and dynamic light scattering angle of 90°. All samples were filtered through 0.8-µm nuclear microporous membranes before measurement.
Effect of counter-ions on the solution conformation and adsorption behaviors of comb-like polycarboxylates on calcium carbonate
Published in Journal of Dispersion Science and Technology, 2019
Qian Zhang, Qianping Ran, Xin Shu, Yong Yang, Cheng Yu
Measurement for static light scattering (SLS) and dynamic light scattering (DLS) experiments were determined by means of a light scattering spectrometer (ALV/CGS-3, ALV, Germany) using a multi-τ digital time correlation (LSE-5004, ALV, Germany) with a He-Ne laser (λ0= 632 nm, 22 mW). Eventually, the specific refractive index increment (dn/dC) value of samples was conducted by BI-DNDC (DNDC-2010, λ = 620 nm, WGE, Germany).
Structure and interaction of therapeutic proteins in solution: a combined simulation and experimental study
Published in Molecular Physics, 2023
Suman Saurabh, Zongyi Li, Peter Hollowell, Thomas Waigh, Peixun Li, John Webster, John M. Seddon, Cavan Kalonia, Jian R. Lu, Fernando Bresme
Regarding inter−protein interactions, we found that interaction strength depends considerably on the ff parameters. The gromos ff predicts a strong, attractive interaction between Fc fragments (). The state-of-the-art ff charmm indicates a weaker attraction () with tips3p. These differences in attractive interactions result in disparate virial coefficients. We obtained a very large negative value with the gromos ff indicating strong protein interactions. charmm predicts slightly negative viral coefficients, with values consistent in magnitude, with those reported in experiments of smaller proteins (lysozyme). Regarding the Fab fragments, the charmm virial coefficient is positive, indicating repulsion, compatible with the high electrostatic charge of Fab (+11e) at pH=7. Our Static light scattering experiments show that Fc features a strong negative virial coefficient in the absence of buffer, indicating strong protein attraction. However, Fab features a positive virial coefficient indicating protein repulsion. This experimental behaviour is reproduced by the charmm ff , while gromos predicts strong attraction (negative virial coefficients) for Fab and Fc fragments. These results support the idea that gromos proteins have a stronger hydrophobic character. We note, however, that the computation of virial coefficients for these complex proteins is challenging due to the configurational space determining the potential of mean force. To calculate our potentials of mean force, we chose similar reaction coordinates for the different systems to ensure a consistent comparison of the results obtained with different models. It will be interesting to expand our investigation by using e.g. enhanced sampling techniques to compute PMFs along other reaction coordinates, which should allow the quantification of the virial coefficients taking into account non-spherical protein geometries. Albeit more challenging, the PMF computations using the methods discussed in this work, might be extended to other fragment pairs like Fab-Fc, as well as full antibodies, taking advantage of more advanced enhanced sampling techniques.