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Dynamic Light Scattering

Dynamic light scattering (DLS), sometimes referred to as Quasi-Elastic Light Scattering (QELS), is a non-invasive, well-established technique for measuring the size and size distribution of molecules and particles typically in the submicron region, and with the latest technology lower than 1nm. Dynamic light scattering (DLS) is often used to determine the size of particles in suspension and or polymers in a solution. We cover off a number of dynamic light scattering (DLS) articles here in our ever growing dynamic light scattering (DLS) blog category.

Dynamic Light Scattering, Kinexus, Laser Diffraction, Mastersizer, Nanoparticle Tracking Analysis, Nanosight, Rheometry, Size Exclusion Chromatography, Tech Talk, X-Ray Diffraction (XRD), Zetasizer »

[5 Dec 2017 | ]

It was my great pleasure to present as part of the Worcestershire Innovation Network at their WINN Wednesday event on the 22nd of November, showcasing the best in innovation across Worcestershire.
This included a local company which makes artificial kneecaps and hips, an insight into the building of genomics studies of patients with rare diseases and cancers, an update on the appeal to get a state-of-the-art surgical robot for removal of prostate tumors (reducing discomfort, scarring and hospital stay post-operation). Jess Antley, head of WINN, also gave an update on a new shared space/collaboration …

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Differential Scanning Calorimetry, Dynamic Light Scattering, MicroCal, Molecular size, Molecular structure, Particle size, Protein Aggregation, Tech Talk, Zetasizer »

[16 Nov 2017 | ]

Measuring aggregation temperature using the Zetasizer

In dynamic light scattering (DLS), the hydrodynamic size and size distribution of particles in solution can be obtained.  It may be of interest to examine this measurement as a function of time and temperature, or as a ‘trend’, as it is called in the Malvern Zetasizer software.  For biological protein samples, this temperature trend is particularly interesting: although at low temperatures a protein may be stable and show repeatable size (and scattering intensity) measurements, typically at some elevated temperature (Tagg), protein molecules will show a tendency …

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Dynamic Light Scattering, Molecular size, Molecular weight, Static Light Scattering, Zetasizer »

[2 Nov 2017 | ]

Molecular weight measurements with the Zetasizer software?
First a few words of caution: molecular weight or Mw measurements in general are not easy, require time, good sample preparation skills as well as patience. If you are new to the Malvern Zetasizer it might be best to familiarize yourself first with the rapid, user-friendly, and quite forgiving technique of dynamic light scattering (DLS).
OK, with that out of the way, the software can handle static light scattering with the relatively simple concentration series method. All that’s required is

a scattering standard (which is usually …

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

[26 Sep 2017 | ]

Is there a maximum viscosity for DLS measurements?
 
The Malvern Zetasizer can determine particle size by dynamic light scattering (DLS). In this technique, the intensity fluctuations are analyzed to find the corresponding diffusion coefficient that led to the fluctuations. The translational diffusion coefficient Dt of a particle is inversely related to its size and the viscosity of the dispersant (or more accurately the hydrodynamic radius rH and viscosity η).

This relationship can be used to predict detectability limits of the technique in general, and this is how we explore the idea of …

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Archimedes, Binding affinity and Kd, Chemical identification, Differential Scanning Calorimetry, Dynamic Light Scattering, Gel permeation chromatography, Image Analysis, Label-free analysis, MicroCal, Microcalorimetry, Morphologi G3-ID, Nanoparticle Tracking Analysis, Nanosight, Particle concentration, Particle shape, Particle size, Protein Aggregation, Raman spectroscopy, Resonant mass measurement, Rheology, Size Exclusion Chromatography, Taylor Dispersion Analysis, Tech Talk, Viscosizer TD, Viscotek, Zetasizer »

[21 Sep 2017 | ]

I know this sounds like the beginning of a bad joke, but in this case, it was actually the beginning of the 2017 Colorado Protein Stability Conference, held in July at Beaver Run Resort in Breckenridge, Colorado. In attendance was a range of scientists and researchers from all over the world, with one common subject in mind: Protein Stability.

One of the highlights of this conference was the pre-conference workshop. This was a free workshop for all attendees of the conference, which was sponsored by Malvern Panalytical. The workshop included a range …

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

[22 Aug 2017 | ]

Zetasizer: 21CFR? Electronic Record/Electronic Signature? Test Schedule?
 

The Malvern Zetasizer is an extremely versatile measurement system. By far the most systems are used in academic and industry research laboratories, for example in fundamental research, drug discovery, or formulation optimization. However, a significant number of installations are in operation in “controlled” environments, such as for quality control in pharmaceutical companies. Here documentation and compliance with good manufacturing standards GMP is critically important, and a specific version of the operating software exist that locks down standard operating procedures (SOP) with limited ability (based …

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Dynamic Light Scattering, Electrophoretic light scattering, Laser Diffraction, Particle size, Zeta potential, Zetasizer »

[3 Aug 2017 | ]

Intralipid-Lipid emulsions

Lipid emulsions are administered intravenously for a variety of purposes:

To help feed patients with temporary difficulty in ingesting food orally
For better transport of lipophilic drugs (fat-friendly active ingredient (API) which is not soluble in water)
For controlled release of drugs (size related to uptake and retention)
To decreasing adverse reactions to drugs
To improve targeting of drugs
In emerging gene therapies for cellular and gene delivery, and personalized medicine

Control and understanding of colloidal properties – such as droplet size and zeta potential – enable the design and optimization of appropriately stable emulsions. The …

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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 …

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Dynamic Light Scattering, Tech Talk, Zetasizer »

[11 Jul 2017 | ]

A webinar entitled “DLS in 30 Minutes” was given in June which attracted a very large audience. The presentation introduced dynamic light scattering and covered the principles of the technique, a discussion of how the measurement is performed, how the data is analyzed and how the results obtained should be interpreted.
We were inundated with various questions during the webinar and we only had time to answer a few on the day. The remainder of questions were answered via e-mail but we thought it would be good to share some of …

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

[20 Jun 2017 | ]

Three methods to verify dynamic light scattering systems
If you are a meticulous researcher you may want to test your new Zetasizer. Is it really providing the correct size? One of the advantages of dynamic light scattering is that there are no tweakable adjustments, it is all physics: laser wave length, scattering angle, refractive index of the dispersant are all known in advance and are given parameters for the optical setup and sample. Nevertheless, it is a good idea to check and verify the performance of the system. One of the …

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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 …

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Dynamic Light Scattering, Meet the Experts, Taylor Dispersion Analysis, Tech Talk, Viscosizer TD, Zetasizer »

[18 May 2017 | ]

Matt McGann and I will be representing Malvern at the upcoming annual UD Biophysical Characterization Workshop, sponsored by CBST (Center for Biomanufacturing Science & Technology), BITC (Biomolecular Interaction Technologies Center), and the University of Delaware, on June 6, 2017, hosted by Professor Christopher Roberts.
This year’s workshop will consist of three days of short courses and small-group demonstrations of the principles and commercial technologies for characterization of protein solutions and related colloidal systems, focusing specifically on static and dynamic light scattering, electrophoresis (DLS, ELS), and Taylor Dispersion Analysis (TDA).
Matt has been …

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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 …

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Corporate, Customer experience, Dynamic Light Scattering, Inside Malvern Panalytical, Zetasizer »

[25 Apr 2017 | ]

Exposition at scientific meetings:
How useful are they and can they help me to get a job?
A brief insight from the ACS meeting
If you follow my writings, you’d probably expect more detail about Dynamic Light Scattering (DLS)… However, today I’d like to report on a recent conference we went to, the national meeting of the American Chemical Society, otherwise known as ACS. It is the world’s largest scientific society by number with close to 160k members.  There were over 17k registrants at the San Francisco meeting earlier this month, quite a turnout. With the constant …

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Dynamic Light Scattering, Electrophoretic light scattering, Meet the Experts, Static Light Scattering, Zeta potential, Zetasizer »

[16 Mar 2017 | ]

Recently, I hosted a webinar which discussed what surface zeta potential is and how it can be measured. The webinar attracted huge interest and it was a pleasure to see so many people attending and asking some excellent questions. In fact, there were so many questions asked, that we ran out of time at the end of the webinar and had to answer many of them via e-mail. Some of these are listed below.
The webinar discussed the zeta potential of solid, planar surfaces (rather than colloidal dispersions or molecular solutions) …

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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 …

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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, Rheology, Rheometry, 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 …

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Dynamic Light Scattering, Gel permeation chromatography, Malvern Panalytical Events, Meet the Experts, Nanoparticle Tracking Analysis, Size Exclusion Chromatography, Zeta potential »

[26 Jan 2017 | ]

We will be attending Pittcon 2017 in Chicago, Illinois March 5th – 9th and once again we are pleased to feature a number of our recognized characterization experts who will be presenting a variety of short courses throughout the week.
Time is running out, so don’t miss out on the early bird deadline for discounted admission which ends on February 18th.
Below is a listing of our available short course offerings.
We look forward to seeing you in Chicago at one of our short courses and our Booth #2416.
Sunday, March 5, 2017 – 8:30 AM
Light Scattering …

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Dynamic Light Scattering, Particle size, Zetasizer »

[23 Jan 2017 | ]

Over the years one of the frequently asked questions that stands out in the data analysis of dynamic light scattering results is the issue about which size one should report.
 
 
 
Here is an example of just such an email I received this month:
“We have several data sets with low PDI (<0.1), single exponential decay, low cumulant fit error(~10^(-4)).  The intensity-distribution size and the cumulant fit size are similar.  But the number-distribution size (d=33 nm)and size obtained by cumulant fit(d=47 nm) are very different.  In this case, should we trust the number-distribution size …

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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 …

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