scholarly journals Analytical Centrifugation

2020 ◽  
Author(s):  
Keyword(s):  
Analytical Centrifugation

scholarly journals Plasma glutathione status as indicator of pre-analytical centrifugation delay

2020 ◽  
Author(s):  
Tomin Tamara ◽  
Natalie Bordag ◽  
Elmar Zuegner ◽  
Abdullah Al-Baghdadi ◽  
Maximilian Schinagl ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
Time Dependent ◽  
Dependent Manner ◽  
Prolonged Incubation ◽  
Glutathione Status ◽  
Potential Marker ◽  
Analytical Centrifugation ◽  
Plasma Glutathione ◽  
Downstream Analysis

Prolonged incubation of blood prior to plasma preparation can significantly influence the quality of the resulting data. Different markers for this pre-clinical variability have been proposed over the years but with limited success. In this study we explored the usefulness of glutathione (GSH) status, namely ratio of reduced to oxidized glutathione (GSH/GSSG), as potential marker of plasma preparation delay. For that purpose, blood from 20 healthy volunteers was collected into tubes with a cysteine quencher (N-ethylmaleimide; NEM) for GSH stabilization. Plasma preparation was delayed at room temperature for up to 3 hours and every hour, a plasma sample was prepared and the GSH/GSSG ratio measured. We report that over the course of the investigation, plasma concentrations of both GSH and GSSG increased linearly (R2 = 0.99 and 0.98, respectively). Since GSH increased at a much faster rate compared to GSSG, the GSH/GSSG ratio also increased linearly in a time dependent manner (R2 = 0.99). As GSH is an intracellular antioxidant, we speculated that this might stem from ongoing blood hemolysis, which was confirmed by the time dependent rise in lactate dehydrogenase (LDH) activity in the plasma samples. Moreover, we demonstrate that the addition of the thiol alkylating reagent NEM directly to the blood tubes does not seem to influence downstream analysis of clinical parameters. In conclusion we propose that the glutathione status could be used as an indicator of the centrifugation delay prior to plasma preparation.

Towards a Framework for Evaluating and Reporting Hansen Solubility Parameters: Applications to Nano and Micron Scale Particle Dispersions

2021 ◽  
Author(s):  
Shalmali Bapat ◽  
Stefan O. Kilian ◽  
Hartmut Wiggers ◽  
Doris Segets
Keyword(s):  
Continuous Phase ◽  
Solubility Parameters ◽  
Hansen Solubility Parameters ◽  
Ranking List ◽  
Knowledge Based ◽  
Complex Interactions ◽  
Analytical Centrifugation ◽  
Scale Particle ◽  
Hansen Solubility

<p>A thorough understanding of complex interactions within particulate systems is a key for knowledge-based formulations. Hansen solubility parameters (HSP) are widely used to assess the compatibility of the dispersed phase with the continuous phase. At present, the determination of HSP is often based on a liquid ranking list obtained by evaluating a pertinent dispersion parameter using only one pre-selected characterization method. Furthermore, one cannot rule out the possibility of subjective judgment especially for liquids for which it is difficult to decipher the compatibility or underlying interactions. As a result, the end value of HSP might be of little or no information. To overcome these issues, we introduce a generalized technology-agnostic combinatorics-based approach. We discuss the principles of the approach and the implications of evaluating and reporting particle HSP values. We demonstrate the approach by using SiN<sub>x</sub> particles. We leverage the analytical centrifugation data to evaluate stability trajectories of SiN<sub>x</sub> dispersions in various liquids to deduce particle-liquid compatibility. </p>

Analytical centrifugation

2020 ◽  
pp. 225-247
Author(s):  
Wendel Wohlleben ◽  
Victoria Anne Coleman ◽  
Douglas Gilliland
Keyword(s):  
Analytical Centrifugation

scholarly journals Measuring the size and density of nanoparticles by centrifugal sedimentation and flotation

2018 ◽  
Vol 10 (15) ◽  
pp. 1725-1732 ◽  
Author(s):  
Caterina Minelli ◽  
Aneta Sikora ◽  
Raul Garcia-Diez ◽  
Katia Sparnacci ◽  
Christian Gollwitzer ◽  
...  
Keyword(s):  
Polystyrene Nanoparticles ◽  
Analytical Centrifugation

Analytical centrifugation in sedimentation and flotation modes is used to measure both the size and density of polystyrene nanoparticles.

Exhibitive Nano-to-Micron Scale Sedimentation Dynamics of Colloidal Formulations Through Direct Visualization

2020 ◽  
Author(s):  
Shalmali Bapat ◽  
Doris Segets
Keyword(s):  
Fuel Cell ◽  
Colloidal Stability ◽  
Silica Nanoparticle ◽  
Data Interpretation ◽  
Colloidal Systems ◽  
Time Resolved ◽  
Knowledge Based ◽  
Sedimentation Behavior ◽  
Nanoparticle Dispersions ◽  
Analytical Centrifugation

The study of sedimentation behavior of nanoparticle dispersions is important for revealing particle size and colloidal stability characteristics. Quantitative appraisal of real-world colloidal systems in their native state, is key for replacing prevailing empiricism in formulation science by knowledge-based design. Herein, we choose fuel cell inks as one case-example amongst many other possibilities to present a new visualization technique, called <i>Transmittogram</i>. This technique readily depicts the time-resolved settling behavior of solid-liquid dispersions, measured by analytical centrifugation (AC). Although AC enables the causal examination of agglomeration, settling, and creaming behavior of dispersions, along with its consequent effect on structure formation and product properties, the understanding of the main transmission readout is often non-intuitive and complex. Transmittograms are, therefore, the missing link for straightforward data interpretation. First, we illustrate the utility of transmittogram analysis using model silica nanoparticle systems and further validate it against known characteristics of the system. Then, we demonstrate the application of transmittograms to characterize fuel cell inks, showing the strength of the approach in deconvoluting and distilling information to the reader. Finally, we discuss the potential of the technique for routine analysis using analytical centrifugation.<br>

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