scholarly journals New amphiphilic glycopolymers by click functionalization of random copolymers – application to the colloidal stabilisation of polymer nanoparticles and their interaction with concanavalin A lectin

2010 ◽  
Vol 6 ◽  
Author(s):  
Otman Otman ◽  
Paul Boullanger ◽  
Eric Drockenmuller ◽  
Thierry Hamaide
Keyword(s):  
Light Scattering ◽  
Molecular Recognition ◽  
Dynamic Light Scattering ◽  
Concanavalin A ◽  
Triblock Copolymer ◽  
Polymer Nanoparticles ◽  
Vinyl Pyrrolidone ◽  
Random Copolymers ◽  
Long Time ◽  
Polymer Surfactants

Glycopolymers with mannose units were readily prepared by click chemistry of an azido mannopyranoside derivative and a poly(propargyl acrylate-co-N-vinyl pyrrolidone). These glycopolymers were used as polymer surfactants, in order to obtain glycosylated polycaprolactone nanoparticles. Optimum stabilization for long time storage was achieved by using a mixture of glycopolymers and the non-ionic triblock copolymer Pluronic® F-68. The mannose moieties are accessible at the surface of nanoparticles and available for molecular recognition by concanavalin A lectin. Interaction of mannose units with the lectin were evaluated by measuring the changes in nanoparticles size by dynamic light scattering in dilute media.

scholarly journals Multi-Step Concanavalin A Phase Separation and Early-Stage Nucleation Monitored Via Dynamic and Depolarized Light Scattering

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 620 ◽  
Author(s):  
Hévila Brognaro ◽  
Sven Falke ◽  
Celestin Nzanzu Mudogo ◽  
Christian Betzel
Keyword(s):  
Phase Separation ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Protein Interactions ◽  
Concanavalin A ◽  
Early Stage ◽  
Protein Crystallization ◽  
Cluster Formation ◽  
Macromolecular Network

Protein phase separation and protein liquid cluster formation have been observed and analysed in protein crystallization experiments and, in recent years, have been reported more frequently, especially in studies related to membraneless organelles and protein cluster formation in cells. A detailed understanding about the phase separation process preceding liquid dense cluster formation will elucidate what has, so far, been poorly understood—despite intracellular crowding and phase separation being very common processes—and will also provide more insights into the early events of in vitro protein crystallization. In this context, the phase separation and crystallization kinetics of concanavalin A were analysed in detail, which applies simultaneous dynamic light scattering and depolarized dynamic light scattering to obtain insights into metastable intermediate states between the soluble phase and the crystalline form. A multi-step mechanism was identified for ConA phase separation, according to the resultant ACF decay, acquired after an increase in the concentration of the crowding agent until a metastable ConA gel intermediate between the soluble and final crystalline phases was observed. The obtained results also revealed that ConA is trapped in a macromolecular network due to short-range intermolecular protein interactions and is unable to transform back into a non-ergodic solution.

Investigation of Poly(vinyl pyrrolidone) in methanol by dynamic light scattering and viscosity techniques

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Adel Aschi ◽  
Mohamed Mondher Jebari ◽  
Abdelhafidh Gharbi
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Molecular Mass ◽  
Vinyl Pyrrolidone ◽  
Least Squares Regression ◽  
Particle Structure ◽  
Crossover Point ◽  
Molecular Weights ◽  
Poly Vinyl Pyrrolidone ◽  
Methanol System

AbstractThe behavior of poly(vinyl pyrrolidone) (PVP) in methanol was examined using several independent methods. The hydrodynamic radius (Rh) of individual samples, over a range of molecular weights (10,000-360,000), was determined using dynamic light scattering (DLS) measurements. Dynamic Light Scattering (DLS) techniques directly probe such dynamics by monitoring and analyzing the pattern of fluctuations of the light scattered from polymer molecules. Some viscosity measurements were also performed to complete the DLS measurements and to provide more information on the particle structure. The results obtained with PVP-methanol system showed that plotting the variation of intrinsic viscosity versus the logarithm of the molecular mass of this polymer, we observe one crossover point. This crossover point appears when we reach the Θ-solvent behavior and delimit two molecular mass regions. The second order least-squares regression was used as an approach and was in excellent agreement with viscometric experimental results.

scholarly journals An Artificial Neural Network Assisted Dynamic Light Scattering Procedure for Assessing Living Cells Size in Suspension

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3425 ◽  
Author(s):  
Dan Chicea
Keyword(s):  
Neural Network ◽  
Time Series ◽  
Artificial Neural Network ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Training Procedure ◽  
Particle Size Range ◽  
Processing Procedure ◽  
Long Time ◽  
Artificial Neural

Dynamic light scattering (DLS) is an essential technique used for assessing the size of the particles in suspension, covering the range from nanometers to microns. Although it has been very well established for quite some time, improvement can still be brought in simplifying the experimental setup and in employing an easier to use data processing procedure for the acquired time-series. A DLS time series processing procedure based on an artificial neural network is presented with details regarding the design, training procedure and error analysis, working over an extended particle size range. The procedure proved to be much faster regarding time-series processing and easier to use than fitting a function to the experimental data using a minimization algorithm. Results of monitoring the long-time variation of the size of the Saccharomyces cerevisiae during fermentation are presented, including the 10 h between dissolving from the solid form and the start of multiplication, as an application of the proposed procedure. The results indicate that the procedure can be used to identify the presence of bigger particles and to assess their size, in aqueous suspensions used in the food industry.

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