It is inherently challenging to analyze nanoparticles such as protein aggregates and other colloids. These particles are too small to image using visible light and must be imaged using laborious electron or scanning microscopy. Dynamic light scattering (DLS) and laser diffraction have been used to establish size distribution and particle size.
DLS and laser diffraction methods are quick and accurate for some samples, however, as they are ensemble methods, high resolution distribution data cannot be obtained.
Ultramicroscope and nanoparticle tracking have been used with only partial success since the broad range of sizes existing in many samples means that scattering from the large particles is bright enough to saturate the detector and remove any hope of learning about smaller particles. Until now, there was no instrument for regular high resolution size distribution analysis.
The ViewSizer™ 3000 leverages innovative software and hardware to resolve these long-standing issues and provides real distribution data for all particle sizes, and mixtures of sizes, from 10 nm to 15 µm. The instrument visualizes and records images of scattered light from individual nanoparticles in liquid suspensions.
This video data is then used to establish particle movement and deduce particle size using the Stokes-Einstein relationship. Additionally, since the illuminated sample volume is well known, particle number concentration is easily determined. From a single measurement, two important pieces of data are established: particle size distribution and particle concentration, even for polydisperse samples.
The screen capture from an analysis on the ViewSizer™ 3000 illustrated above shows its unmatched ability to visualize particles even in highly polydisperse samples. This capability enables unparalleled insights into the user’s nanoparticles, whether they are from biological, pharmaceutical, aquatic, industrial, agricultural or other sources.
How Does It Work?
The instrument characterizes larger, micron-sized particles by analyzing gravitational settling and nanoparticles by analyzing their thermal-induced motion (Brownian motion). The optical system includes innovative multispectral illumination and detection techniques that enable video recording of scattered light images from varied sizes of separate particles at the same time
The figure below shows a schematic of light scattering. Particles are illuminated and images of scattered light images from the individual particles are magnified by a microscope objective. Videos of those images are recorded for analysis by the ViewSizer™ 3000 software.
The motion of every single particle is tracked in the software to determine the diffusion coefficient, and, from that, it is possible to calculate the size of each particle. This is accomplished by taking advantage of modern high resolution video cameras and computer graphics processing speed.
The particle size distribution, including the concentrations of each constituent in a mixture, is readily discerned as shown below.
A vital improvement of this system is its ability to work with the extremely large dynamic range of scattered light intensity produced by differently-sized nanoparticles coexisting in a polydisperse sample. The combination of advanced software and novel optics, based on multiple wavelengths of light, enables this technical feat.
The ViewSizer™ 3000 technology from MANTA Instruments (MANTA, for Most Advanced Nanoparticle Tracking Analysis) is an absolute and elegant method that does not require knowledge of particle material properties such as refractive index or calibration standards.
Particle Kinetic Processes
The ViewSizer™ 3000’s unique capability to visualize, measure, and count broad-ranging sizes of micron and nano sized particles in the same sample enables unparalleled characterization of many particle kinetic procedures including: self-assembly of polymers, dissolution of active pharmaceutical ingredients, aggregation of proteins, crystallization of food and pharmaceutical products, and particle agglomeration.
In these and other cases, the total process can be seen in real-time and key rate constants can be established. Additionally, process parameters such as temperature, agitation, and concentration can be modified during the analysis. Insights from kinetic experiments performed with the ViewSizer™ 3000 help with the identification of suitable process conditions and efficient formulations.
Count and Concentration
For process yield and several other applications, it is useful to discern particle concentration. Since the illuminated sample volume is known together with the number of particles imaged, particle concentration is easily established.
The ViewSizer™ software was built with the user in mind. Data collection can begin with only a few clicks of the mouse and the end results are available in several formats to help all users. Particle visualization is an essential component of each analysis carried out on the ViewSizer™ 3000. All data can be exported for additional analysis or preparation of publication quality graphs.
The main features of the ViewSizer™ 3000 particle analysis system are as follows:
- Visualization of particles
- Reproducible and accurate measurements of:
- Particle size distribution even for the most polydisperse samples
- Particle number concentration
- Particle kinetic processes, such as particle aggregation, dissolution, swelling, shrinkage and growth rates
The main specifications of the ViewSizer™ 3000 particle analysis system are as follows:
|Range of Particle Sizes Measured *
||10 nm to 15 µm
|Typical Sample Volume
||350 µL to 1 mL
|Typical Sample Concentration
||5 x 106 to 2 x 108 particles/mL
|Sample Temperature Range (Controlled)
||10 °C to 50 °C, ± 0.1 °C
||55 cm W x 66 cm D x 35 cm H
||15 °C to 30 °C with < 85% RH
* Sample dependent
The improved particle analysis achieved with the ViewSizer™ 3000 system can be beneficial to the following applications:
- Chemical Mechanical Polishing
- Colloid Stability
- Environmental Sciences
- Exosomes, microvesicles, and other biological particles
- Metal Powders
- Pigments and Inks
- Protein Aggregation
- Water Quality and Treatment