Particle-size and velocity measurements in flowing conditions using dynamic light scattering

Leung, Alfred B.; Suh, Kwang I.; Ansari, Rafat R.

doi:10.1364/ao.45.002186

Cited by 56 publications

(56 citation statements)

References 3 publications

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“…In contrast to the typical DLS measurement setup, the time correlation in the on‐line measurement loop was not only influenced by diffusion but also by convective flow (Berne & Pecora, ). It has been previously demonstrated that the convective flow results in increased estimated diffusion coefficients and thus in reduced particle diameters (Leung, Suh, & Ansari, ). The effect was shown to be more pronounced for larger particles.…”

Section: Discussionmentioning

confidence: 99%

Process monitoring of virus‐like particle reassembly by diafiltration with UV/Vis spectroscopy and light scattering

Rüdt

Vormittag

Hillebrandt

et al. 2019

Biotech & Bioengineering

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Virus‐like particles (VLPs) have shown great potential as biopharmaceuticals in the market and in clinics. Nonenveloped, in vivo assembled VLPs are typically disassembled and reassembled in vitro to improve particle stability, homogeneity, and immunogenicity. At the industrial scale, cross‐flow filtration (CFF) is the method of choice for performing reassembly by diafiltration. Here, we developed an experimental CFF setup with an on‐line measurement loop for the implementation of process analytical technology (PAT). The measurement loop included an ultraviolet and visible (UV/Vis) spectrometer as well as a light scattering photometer. These sensors allowed for monitoring protein concentration, protein tertiary structure, and protein quaternary structure. The experimental setup was tested with three Hepatitis B core Antigen (HBcAg) variants. With each variant, three reassembly processes were performed at different transmembrane pressures (TMPs). While light scattering provided information on the assembly progress, UV/Vis allowed for monitoring the protein concentration and the rate of VLP assembly based on the microenvironment of Tyrosine‐132. VLP formation was verified by off‐line dynamic light scattering (DLS) and transmission electron microscopy (TEM). Furthermore, the experimental results provided evidence of aggregate‐related assembly inhibition and showed that off‐line size‐exclusion chromatography does not provide a complete picture of the particle content. Finally, a Partial‐Least Squares (PLS) model was calibrated to predict VLP concentrations in the process solution. Q 2 values of 0.947–0.984 were reached for the three HBcAg variants. In summary, the proposed experimental setup provides a powerful platform for developing and monitoring VLP reassembly steps by CFF.

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Section: Discussionmentioning

confidence: 99%

Process monitoring of virus‐like particle reassembly by diafiltration with UV/Vis spectroscopy and light scattering

Rüdt

Vormittag

Hillebrandt

et al. 2019

Biotech & Bioengineering

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“…DLS measurements were successfully applied to analyse sample solutions in flow at different stages of protein folding by Gast et al (1997). A particular fibre optic DLS probe was used by Leung et al (2006) to characterize latex particles in flow, pointing at a variety of potential industrial applications to count and determine the size of particles for quality control in flow. The application of DLS in a shear flow and in a microfluidic channel was mathematically described by Destremaut et al (2009), taking the channel dimensions, shear rates, velocity profile of a Poiseuille flow and interferences of different Doppler shifts into account.…”

Section: Introductionmentioning

confidence: 99%

Multi-channelin situdynamic light scattering instrumentation enhancing biological small-angle X-ray scattering experiments at the PETRA III beamline P12

Dierks¹,

Blanchet

Graewert

et al. 2018

J Synchrotron Radiat

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Small-angle X-ray scattering (SAXS) analysis of biomolecules is increasingly common with a constantly high demand for comprehensive and efficient sample quality control prior to SAXS experiments. As monodisperse sample suspensions are desirable for SAXS experiments, latest dynamic light scattering (DLS) techniques are most suited to obtain non-invasive and rapid information about the particle size distribution of molecules in solution. A multi-receiver four-channel DLS system was designed and adapted at the BioSAXS endstation of the EMBL beamline P12 at PETRA III (DESY, Hamburg, Germany). The system allows the collection of DLS data within round-shaped sample capillaries used at beamline P12. Data obtained provide information about the hydrodynamic radius of biological particles in solution and dispersity of the solution. DLS data can be collected directly prior to and during an X-ray exposure. To match the short X-ray exposure times of around 1 s for 20 exposures at P12, the DLS data collection periods that have been used up to now of 20 s or commonly more were substantially reduced, using a novel multi-channel approach collecting DLS data sets in the SAXS sample capillary at four different neighbouring sample volume positions in parallel. The setup allows online scoring of sample solutions applied for SAXS experiments, supports SAXS data evaluation and for example indicates local inhomogeneities in a sample solution in a time-efficient manner. Biological macromolecules with different molecular weights were applied to test the system and obtain information about the performance. All measured hydrodynamic radii are in good agreement with DLS results obtained by employing a standard cuvette instrument. Moreover, applying the new multi-channel DLS setup, a reliable radius determination of sample solutions in flow, at flow rates normally used for size-exclusion chromatography-SAXS experiments, and at higher flow rates, was verified as well. This study also shows and confirms that the newly designed sample compartment with attached DLS instrumentation does not disturb SAXS measurements.

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“…The setup comprises a semiconductor laser (λ=639.4 nm, power=80 μW), a photodetector (avalanche photodiode based photon counting module), a DLS probe built at NASA for both static and dynamic light scattering configurations (scattering angle=163.0 degrees, focal length=16 mm, scattering volume ~50 μm 3 ), a translation stage with a motorized actuator, for accurate positioning, (to which the DLS fiber optic probe is mounted on a multi axis translation stage), and a Pentium based computer containing a digital correlator card (BI-9000) for data acquisition. This system has been previously used in protein crystal growth experiments,30 particle sizing applications in flowing dispersions,31 in protein characterization of ocular tissues in live animals,32 and in clinical ophthalmic applications for the early detection of cataract 33. Only the static (total intensity) light scattering measurements were made in the experiments reported here.…”

Section: Experimental Methodsmentioning

confidence: 99%

Isoelectric Focusing in a Drop

Weiss

Hayes

García³

et al. 2010

Langmuir

Self Cite

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A novel approach to molecular separations is investigated using a technique termed droplet-based isoelectric focusing. Drops are manipulated discretely on a superhydrophobic surface, subjected to low voltages for isoelectric focusing, and split-resulting in a preparative separation. A universal indicator dye demonstrates the generation of stable, reversible pH gradients (3-10) in ampholyte buffers and these gradients lead to protein focusing within the drop length. Focusing was visually characterized, spectroscopically verified, and assessed quantitatively by non-invasive light scattering measurements. It was found to correlate with a quantitative model based on 1D steady state theory. This work illustrates that molecular separations can be deployed within a single open drop and the differential fractions can be separated into new discrete liquid elements.

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Particle-size and velocity measurements in flowing conditions using dynamic light scattering

Cited by 56 publications

References 3 publications

Process monitoring of virus‐like particle reassembly by diafiltration with UV/Vis spectroscopy and light scattering

Process monitoring of virus‐like particle reassembly by diafiltration with UV/Vis spectroscopy and light scattering

Multi-channelin situdynamic light scattering instrumentation enhancing biological small-angle X-ray scattering experiments at the PETRA III beamline P12

Isoelectric Focusing in a Drop

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