Electrophoretic light scattering
Electrophoretic Light Scattering (ELS) is a technique used to measure the electrophoretic mobility of particles in dispersion, or molecules in solution. This mobility is often converted to Zeta potential to enable comparison of materials under different experimental conditions. Electrophoretic light scattering (ELS) offers users fast testing of the electrophoretic mobility of particle.
Dynamic Light Scattering, Electrophoretic light scattering, Meet the Experts, Static Light Scattering, Zeta potential, Zetasizer »
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) …
Electrophoretic mobility measurements from proteins: How to protect proteins in an electric field
What is the protein mobility mode?
When applying an electric field to a sample containing protein molecules, there are a few considerations to take into account to avoid “over-stressing” delicate biomolecules. The force a charged object experiences in an electric field is proportional to its charge times the electric field. Therefore the electric field strength (defined by the applied voltage divided by the distance between the electrodes, in V/cm) is more relevant than the absolute value of the applied …
Customer experience, Dynamic Light Scattering, Electrophoretic light scattering, Molecular size, Molecular weight, Particle size, Zeta potential, Zetasizer »
How can I save paper and print a Zetasizer report as a PDF?
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 …
Dynamic Light Scattering, Electrophoretic light scattering, Meet the Experts, Particle size, Protein Aggregation, Zeta potential, Zetasizer »
Adjuvants for vaccination – How size and zeta may be relevant
What is an adjuvant?
Adjuvants are substances which are added to medicines to trigger and enhance an immune response to an antigen. In the USA, the most commonly-used adjuvant is alum, and many vaccines in use today contain some aluminum components to help the vaccine work better. While the exact mechanisms of how adjuvants work is unclear to some extent, a typical adjuvant component is much larger than the antigen or antibody itself, often around 100 nm in radius.
In a paper entitled …
Every once in a while, we get questions about older light scattering systems which predate the Zetasizer Nano series. While it is great to hear that these are still in operation, it can also present us with some challenges. For example, if the system or accessory is no longer in production, and this has been the case for a number of years, are we still able to support it? On the plus side, we have lots of employees that have stayed with Malvern for more than a decade – some …Read the full story »
Differential Scanning Calorimetry, Electrophoretic light scattering, Isothermal Titration Calorimetry, Label-free analysis, Malvern Events, MicroCal, Microcalorimetry, Molecular structure, Protein Aggregation, Raman spectroscopy, Zetasizer »
I had the pleasure of participating in the 5th International Symposium on Higher Order Structure of Protein Therapeutics, also known as HOS2016, sponsored by CASSS. The meeting was at the Renaissance Hotel in Long Beach, California April 11-13, 2016. I was joined by my Malvern colleagues Rajib Ahmed and David Sanborn.
The HOS Symposium is a platform for open discussion of development and optimization of analytical techniques to study HOS of proteins and biopharmaceutical products (including monoclonal antibodies and antibody-drug conjugates), biocomparability, and biosimilars.
Protein higher order structure (HOS) includes the secondary, …
Electrophoretic light scattering, Nanosight, Protein Mobility, Tech Talk, Zeta potential, Zetasizer »
How to perform zeta potential measurement with the diffusion barrier method?
The diffusion barrier method is particularly suitable for low sample volumes and high ionic strength buffers. A “plug” of the sample is carefully injected into the folded capillary cells which is filled with just the buffer (The buffer has to be the same buffer that the protein is prepared in, same conductivity, same pH, same additives, in order to match the sample and the diffusion barrier as closely as possible). In this setup, primarily the zeta potential is of interest, however …Read the full story »
How can the zeta deviation be larger than the mean?
We recently received a phone call from a customer asking about their zeta potential results: When they are measuring electrophoretic light scattering, the zeta potential value for their sample is 15.4mV and the Standard Deviation is 24mV. Why is the Standard Deviation larger than the actual mean Zeta potential ?
To understand this better let’s first look at the concept of M3-PALS . M3 stands for mixed mode measurement: while traditional electrophoretic measurements are performed by measurement of particles at the stationary layer (= a …
Dynamic Light Scattering, Electrophoretic light scattering, Particle size, Tech Talk, Zeta potential, Zetasizer »
We just received an interesting request from a customer and I thought the answer would be worth sharing. Most titrations are performed for pH only, in fact this is how the MPT (=Malvern pH Titrator) got its model name, and there are also additive linear, conductivity (additive log), and dilution methods available besides the standard pH titration. For ultimate flexibility there is yet another way to perform automated measurements:
Advanced titrations with three additive titrants
Specifically the question was: “Is there a way to vary the dosing of each of the titrants? I want to …
Dynamic Light Scattering, Electrophoretic light scattering, Nanoparticle Tracking Analysis, Nanosight, Particle size, Tech Talk, Zeta potential, Zetasizer »
The Consumer Electronics Show (CES) took over Las Vegas once again last week, and this time, quantum dots are the hottest thing happening in TV technology. At CES 2015 LG revealed a 4K quantum dot TV, the UF9400, quickly followed by Samsung‘s own line of Ultra HD TVs featuring quantum dots. Sony was one of the first tech companies off the mark, including quantum dot technology in some of its high end TVs back in 2013.
Quantum dots are uniquely highly scattering nanoparticles that can be used for image enhancement. These light-emitting semiconductor nanocrystals …
What is surface zeta potential and how to measure it?
The Zetasizer Nano has an optional Surface Zeta Potential cuvette, which can be used to help gain an understanding of the charge at interfaces . The surface zeta potential cell is intended for the measurement of the zeta potential at the surface of a flat material in an aqueous environment.
The Zetasizer has been around for a few years, and the Zetasizer series now includes several models (90 degrees, backscattering, size and zeta, flowmode for chromatography detection, automated plate sampler). One of …
Dynamic Light Scattering, Electrophoretic light scattering, Molecular weight, Size Exclusion Chromatography, Tech Talk, Viscotek, Zetasizer »
Hyaluronic Acid Analysis
As I am new to blogging I think a brief introduction would be good. My name is John Stenson, I am the Product Technical Specialist looking after the Size Exclusion Chromatography (SEC) related detector systems, known as our Viscotek product line. I am most interested in using our technologies to investigate the properties of Proteins and Biopolymers.
My role is extremely varied with one of the most enjoyable aspects attending conferences, presenting exciting new research we have carried out and talking with other scientists. As part of this I …
Dynamic Light Scattering, Electrophoretic light scattering, Malvern Events, Zeta potential, Zetasizer »
For regular readers of Materials Talks wondering who I am, I recently joined Malvern Instruments as a Social Media Manager. I’ll be running Materials Talks, as well as our other social media profiles, such as Twitter and Linkedin, so you will hear from me from time to time.
In this, my first post for Materials Talks, I want to tell you about a great event that will be of particular interest to those working in drug and biotherapeutics research, development and formulation, from Project Managers to Bench Scientists. Are you interested …
Dynamic Light Scattering, Electrophoretic light scattering, Image Analysis, Insitec, Laser Diffraction, Mastersizer, Morphologi G3, Parsum, Particle shape, Particle size, Rheological and Viscosity, Spatial Filter Velocimetry, Spraytec, Sysmex FPIA-3000, Tech Talk, Zeta potential, Zetasizer »
Particle Characterization Explained
There is a wide range of commercially available particle characterization techniques that can be used to measure particulate samples. Each has its relative strengths and limitations and there is no universally applicable technique for all samples and all situations.
Which particle characterization techniques do I need?
A number of criteria must be considered when deciding which particle characterization techniques you need:
• which particle properties are important to me?
• what particle size range do I want to work over?
• are my samples polydisperse i.e. do I need a wide dynamic range?
Corporate, Dynamic Light Scattering, Electrophoretic light scattering, Malvern Events, Meet the Experts, Microrheology, Protein Mobility, Zeta potential, Zetasizer »
After much discussion about the forthcoming addition to the Zetasizer Nano range, and build up of excitement around the launch, I can announce that the Zetasizer Nano ZSP has been officially released and is available to buy from your local Malvern office.
The ZSP is complimentary to the existing Zetasizer Nano instruments, and is now the premium system in the range. It can be used for the measurement of size, electrophoretic mobility of proteins, zeta potential of nanoparticles and surfaces, and optionally the microrheology of protein and polymer solutions. In addition to …