Home » Archive

Molecular size

Measure absolute molecular size without calibration.

Differential Scanning Calorimetry, Dynamic Light Scattering, Meet the Experts, MicroCal, Molecular size, Molecular weight, OMNISEC, Particle concentration, Protein Aggregation, Size Exclusion Chromatography, Taylor Dispersion Analysis, Zetasizer »

[18 Jul 2017 | ]

Monoclonal Antibodies – or mAbs for short

Since many of these mAbs require refrigeration we had used dynamic light scattering (with a Zetasizer) to show the formation of aggregates after freeze-thaw cycles (for details see application note “Effect of storage conditions on Immunoglobulin“). These could be seen both in the increased polydispersity index (PDI) and the appearance of a large-size aggregate peak in the intensity size distribution as shown to the right. The area under the peak gives an indication of the presence of the large aggregates but is not suited for …

Read the full story »

Customer experience, Dynamic Light Scattering, Electrophoretic light scattering, Molecular size, Particle size, Zeta potential, Zetasizer »

[25 May 2017 | ]

A challenge to all new Zetasizers!
 
The Zetasizer is so simple to use that the majority of Zetasizer (user)s just “dive in” and find out how to operate the system.
By design it is (almost) indestructable, so what can go wrong? Not much – nevertheless, you might be able to get even more use and benefit from your system with a little preparation.
 
Free eLearning video – really!
If you are relatively new to the Zetasizer then take a look at our free eLearning introductory course. It was meant as a teaser for the …

Read the full story »

Archimedes, Chemical identification, Fluorescence Detection, Label-free analysis, Malvern Panalytical Events, MicroCal, Microcalorimetry, Molecular size, Molecular structure, Molecular weight, Morphologi G3-ID, Nanosight, Particle concentration, Particle shape, Particle size, Protein Aggregation, Protein higher order structure, Protein Mobility, Viscosizer TD, Zeta potential, Zetasizer »

[16 May 2017 | ]

With Pre-Conference Workshop on Biophysical Characterization and Particle Analysis
 

Date: July 17th – 20th.
We at Malvern know that protein stability is important in numerous disciplines, ranging from basic and medical biochemistry to pharmaceutical sciences. However, it is rare that researchers from all the relevant areas can join to discuss the critical issues in the field. The 2017 Colorado Protein Stability Conference provides a unique forum for this exchange of information. The topics to be covered include protein folding, dynamics and thermodynamic stability; amyloidosis and protein aggregation; and stability, formulation, analysis and processing …

Read the full story »

Customer experience, Dynamic Light Scattering, Molecular size, Particle size, Zeta potential, Zetasizer »

[4 May 2017 | ]

3 stumbling blocks for Report Designer (Zetasizer) – the rule of two
The three most common holdups encountered in the report designer feature are listed here.
Not everyone delves into the depth of the Zetasizer software, but of those who do want to take advantage of the report customization features in the ‘report designer’ nearly everyone runs into at least one of these three common mistakes:

1. Folder locations – there are two!
The Zetasizer software is typically installed in a (hidden) Windows directory like  C:\Program Files\Malvern Instruments\Zetasizer Software and that’s good. However, if …

Read the full story »

Dynamic Light Scattering, Molecular size, Particle concentration, Particle size, Protein Aggregation, Tech Talk, Zetasizer »

[7 Mar 2017 | ]

How can I use DLS for sample xyz?
What sample concentration / refractive index is needed for reliable DLS size measurements?

Has it been done before?
In Dynamic Light Scattering (DLS) intensity fluctuations in the sample are analyzed to obtain size information on the sample. The technique is applicable to a wide size range from sub-nanometer up to a few microns. In order to obtain a meaningful result, a minimum scattering signal strength must be present. Malvern’s Zetasizer Nano software contains a calculator to help estimate the required minimum concentration.
If anyone else has …

Read the full story »

Binding affinity and Kd, Differential Scanning Calorimetry, Dynamic Light Scattering, Français, Gel permeation chromatography, Image Analysis, Isothermal Titration Calorimetry, Laser Diffraction, Meet the Experts, Molecular size, Nanoparticle Tracking Analysis, Particle concentration, Particle size, Rheological and Viscosity, Rheometry - Rotational, Size Exclusion Chromatography, Static Light Scattering, Zeta potential »

[21 Feb 2017 | ]

Afin de vous apporter un support concret pour utiliser votre système de façon optimale, finaliser vos bonnes pratiques de laboratoire et répondre à vos besoins spécifiques, Malvern organise des formations sur site ou en sessions dans nos 3 agences françaises (Orsay, Lyon et Toulouse).
Voici les dates de toutes les sessions programmées pour 2017 :
CARACTERISATION DES PARTICULES PAR DIFFRACTION LASER
Objectifs : Perfectionner les méthodes de caractérisation des particules en voie sèche et liquide, définir les bonnes pratiques de laboratoire et s’adapter aux besoins spécifiques de chaque installation. Comprendre le principe physique …

Read the full story »

Dynamic Light Scattering, Molecular size, Molecular structure, Particle size, Tech Talk, Zetasizer »

[27 Dec 2016 | ]

How to measure it with DLS?
What virus concentration is needed for reliable DLS size measurements?
 
What is a virus?
In cell biology, a virus is a self assembly of organic molecules (mainly proteins) in the size range 20 nm – 300 nm (diameter). Viruses hold great interest for human gene therapy researchers, and the AAV-2  virus shown to the left is an example.
How to size a virus in solution?

One of the techniques available to size viruses (as well as other biological nanoparticles) is Dynamic Light Scattering (DLS), where intensity fluctuations in a small …

Read the full story »

Gel permeation chromatography, Malvern Panalytical Events, Molecular size, Molecular weight, OMNISEC, Size Exclusion Chromatography, Viscotek »

[8 Dec 2016 | ]

Version Française
The French symposium of the French Group of Studies and Applications of Polymers (GFP) is the major French congress of polymers.
The 45th edition took place recently in Marseille under the bold architecture of the Villa Méditerranée, designed by Stefano Boeri, a committed actor of the Italian political and cultural scene.

During this conference, we presented the benefits of Viscotek SEC MALS 20.
The SEC-MALS 20 multi-angle light scattering detector  can be used on all GPC / SEC systems and especially Malvern’s latest OMNISEC range. The 20 signals of the SEC-MALS detectors connected …

Read the full story »

Français, Gel permeation chromatography, Malvern Panalytical Events, Molecular size, Molecular weight, OMNISEC, Size Exclusion Chromatography, Viscotek »

[8 Dec 2016 | ]

English version
Le colloque national du Groupe Français d’études et d’applications des Polymères (GFP) est le congrès français majeur des polymères.
La 45ème édition s’est déroulée récemment à Marseille sous l’architecture audacieuse de la Villa Méditerranée, conçue par Stefano Boeri, acteur engagé de la scène politique et culturelle italienne.

Durant ce congrès, nous avons présenté les avantages du Viscotek SEC MALS 20.
Le détecteur de diffusion de lumière multi-angle Viscotek SEC-MALS 20 peut être utilisé sur tous les systèmes de GPC/SEC et notamment sur le dernier OMNISEC de la gamme Malvern. Les signaux des 20 détecteurs du SEC-MALS …

Read the full story »

Dynamic Light Scattering, Molecular size, Protein Aggregation, Tech Talk, Zetasizer »

[1 Nov 2016 | ]

α-synuclein promotes vesicle assembly – when size can support theory
 

What is a vesicle?
In cell biology, a vesicle is an (often spherical) assembly of amphiphilic molecules (usually proteins and phospholipids), and is typically sized between 30 nm – 100 nm in diameter. Vesicles are often classified by the type of interaction they are involved with. For extracellular vesicles (or exosomes), this is usually intercellular signal transmission. A particular example of exosomes is synaptic vesicles, which transmit signals between neurons (average size: 40 nm).
In a paper entitled “Structural basis of synaptic vesicle assembly promoted …

Read the full story »

Customer experience, Dynamic Light Scattering, Electrophoretic light scattering, Molecular size, Molecular weight, Particle size, Zeta potential, Zetasizer »

[20 Oct 2016 | ]

How can I save paper and print a Zetasizer report as a PDF?
 
Why print?
The Zetasizer software includes several popular report options. The most frequently used of these is probably the Intensity PSD (M), which gives a compact overview of the results. It lists the z-average and up to three peaks by intensity with their respective mean size, the area under the peak in % intensity and the standard deviation of the peak. In addition, several relevant sample identifiers and measurement conditions, like the sample name,  file name, refractive index of …

Read the full story »

Dynamic Light Scattering, Molecular size, Particle size, Tech Talk, Zetasizer »

[16 Aug 2016 | ]

Why are my particles measuring too small?
The technique of  Dynamic Light Scattering (DLS) has become quite standard in many biophysical characterization labs, often alongside common tools like UV-Vis, SEC, AUC, Fluorescence, NMR, AFM, SAXS, or Mass Spec.  As DLS systems (like the Malvern Zetasizer Nano) have become ever easier to use we see an increasing range of applications and research. By observing and analyzing intensity fluctuations in a sample, we can find the diffusion coefficient and, with known viscosity, the corresponding size. Inevitably, at some point the size measured will not …

Read the full story »

Dynamic Light Scattering, Molecular size, Particle size, Tech Talk, Zetasizer »

[21 Jul 2016 | ]

“What is dynamic light scattering?” Find out in less than 5 minutes!
Although we’ve gone into deeper detail in previous posts , every once in a while it’s nice to recap on the basics. A few years ago, our presentation “Dynamic Light Scattering Primer” was among the top three recordings in the Malvern charts for months in a row. Over the last decade, DLS has  become one of the de facto nanoparticle characterization standard methods. And it’s used not only for nanoparticles, but also for molecules, proteins, drug delivery particles, liposomes, virus like particles, …

Read the full story »

Malvern Panalytical Events, Meet the Experts, Molecular size, Zetasizer »

[23 Feb 2016 | ]

It’s not unusual to see a Malvern Zetasizer in a University laboratory. In fact, there are so many educational institutions taking advantage of the quick and reliable information dynamic light scattering (as well as electrophoretic light scattering) can provide, that it is more likely that there already is a system somewhere on your campus than not.  We are delighted that light scattering plays an integral role in so many academic institutes around the world!  If youre wondering whether there is a system on your campus, just contact our Helpdesk, who …

Read the full story »

Dynamic Light Scattering, Molecular size, Particle size, Tech Talk, Zetasizer »

[26 Jan 2016 | ]

In the Malvern Zetasizer software we measure the intensity auto-correlation function. This is obtained from correlating the scattering intensity with itself. The resulting intensity auto-correlation function is often denoted by the symbol G2(τ) in its normalized form. For Gaussian scattering, there is a relationship between the intensity and the field correlation function, known as the Siegert relation.
If we denote the normalized field correlation function as G1(τ) then under ideal conditions:
G2(τ) = 1 + G1(τ)^2  (In real measurements there would also be a baseline and a signal-to-noise ratio)
Within the Malvern software, …

Read the full story »

Dynamic Light Scattering, Molecular size, Molecular weight, Protein Aggregation, Tech Talk, Zetasizer »

[21 Jan 2016 | ]

How do I know the minimum concentration needed for measuring the size of my protein?

We are asked this question all the time when we are demonstrating the Zetasizer.  Happily, if the Zetasizer software is installed (and it can be downloaded for free, by the way) there is a minimum concentration calculator integrated – so it’s simple! The calculator can be accessed from Tools – Calculators – Concentration Utilities – Minimum Concentration Calculator
Let’s look at a few examples to get an idea of some typical values for your samples. The left …

Read the full story »

Customer experience, Dynamic Light Scattering, Meet the Experts, Molecular size, Zetasizer »

[1 Oct 2015 | ]

Washington University, St Louis, Missouri. October 2, 2015

We were invited to the Nano Research Facility workshop taking place this week in Saint Louis, Missouri.
Starting off Session II on Nanomaterial Sizing, Dr. Ana Morfesis will present her contribution on “Nanoparticle Size Measurements by Dynamic Light Scattering” at 10:00am in Bauer Hall.
 
 
 
 
The afternoon Session III is titled “Hands-on experience for Transmission electron Microscope (TEM), Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM), Dynamic Light Scattering (DLS), and Brunauer Emmet Teller (BET) ”
For the DLS part, a Zetasizer Nano will be available for sample …

Read the full story »

Dynamic Light Scattering, Molecular size, Protein Aggregation, Tech Talk, Zetasizer »

[30 Jul 2015 | ]

Often, pharmaceutical formulations contain therapeutic proteins at relatively high concentration. Under such conditions, the stability of the protein as well as the formulation overall is of significant concern. Great effort is invested in optimizing stability, and particular attention goes to the choice of buffer components. Various components might form part of the ‘final’ recipe including cosolvents (such as polyethylene glycol (PEG), glycerol, ethanol) to reduce the dielectric constant of the buffer and influence electrostatic interactions, chelating agents (citric acid or citrate salt buffers, ethylene-diamine-tetra-acetic acid (EDTA), tris(hydroxymethyl)aminomethane (TRIS), tartaric acid) and …

Read the full story »

Gel permeation chromatography, Molecular size, Molecular structure, Molecular weight, OMNISEC, Size Exclusion Chromatography, Tech Talk »

[14 Jul 2015 | ]

Multi-detector SEC – 10 reasons why protein scientists need one
In a previous post I listed the top ten reasons why a polymer characterization scientist might want to upgrade to multi-detector Gel Permeation Chromatography/Size Exclusion Chromatography, but there are similar points to be made as to why a protein characterization scientist might do the same.  We often focus on the benefits of our own systems but sometimes we may miss the benefits of the basic technique.
If you are a protein characterization scientist and you find yourself thinking, “My UV detector works …

Read the full story »

Molecular size, Molecular structure, Molecular weight, Particle shape, Protein Mobility, Zetasizer »

[30 Jun 2015 | ]

The Zetasizer has some optional advanced protein features that you may not be aware of:
DLS Debye Plot: a dynamic Debye plot of the measured hydrodynamic size as a function of sample concentration to obtain the dynamic Virial coefficient (also known as kd, or interparticle interaction parameter)
Mixture Viscosity: estimates the viscosity of a mixture of dispersants of known viscosity, using the assumption that the total viscosity is a volume fraction weighted sum of the component viscosities. The mean viscosity is based on the volume fraction and the individual viscosities of the component …

Read the full story »