Benefits of Using Nanoparticle Tracking Analysis in Particle Detection

Knowing the size distribution of individual nanoparticles offers a competitive advantage in many Industries and fields of research. Find out how Nanoparticle Tracking Analysis (NTA) instruments like the Malvern NanoSight NS300 can help you detect and size individual nanoparticles using high resolution modelling and reporting.

Why it’s important to detect the size and count of nanoparticles

The production of nanoscale materials includes use and experimentation with a wide range of substances. This brings up a range of considerations to health and safety:

• Is the research conducted safely?
• Does the production of materials pose risks?
• Is the end use of the nanoscale material suitable for the end user?
• Can the materials and associated byproducts be disposed of safely?

Therefore it’s essential that every effort is made to classify nanoparticles and assess their safety and fit for purpose. NTA instruments offer the best opportunity for researchers and scientists to gather accurate data on a range of nanoscale materials.

What are nanoscale materials?

Nanoscale materials are defined as having one relevant length of scale within the nanometer range. Quantum and surface boundary effects cause nanomaterials to exhibit different effects to their bulk counterparts. Nanoscale materials include:

• Nanotubes and nanowires
• Ceramics
• Quantum dots

By measuring these particles with NTA instruments you can gain better insight into their size, distribution, and concentration measurements.

The nanoparticle measurement process

In NTA there is typically a five step process for tracking individual nanoparticles within a sample.

1. Nanoparticle samples are prepared in a water based liquid at a typical concentration rate of between 107 – 109 parts per millilitre.
2. Sample is placed in the sample chamber.
3. The NTA laser illuminates the sample and dispersed light is captured by a high sensitivity microscopic camera.
4. The NTA computer tracks particles and displays modelling visualisation on the screen.
5. This ‘recording’ can then be analysed with a range of outputs.

Nanoparticle Tracking Analysis output

NTA instruments like the Malvern NanoSight NS300 can automatically track a range of different sized particles simultaneously, with frequency size distributions combined with supplementary data on light scattering intensity to design 3D plots of the size and number of individual nanoparticles. Results can also be exported as spreadsheets.

Features of Nanoparticle Tracking Analysis

NTA instruments are the most feature rich devices for nanomaterial measurement of individual particles and size distribution. Features include:

• High resolution particle sizing, per particle
• Live particle scattering suspension view
• Particle count and concentration measurements
• Sphericity and aspect ratio
• Electrophoretic mobility and zeta potential measurement
• Measuring down to 10nm, depending on the material

Applications of Nanoparticle Tracking Analysis instruments

NTA instruments are seeing a high adoption rate worldwide. Between 2006 and 2011 over 300 systems were installed, with 180 peer reviewed open papers published in the same time frame. Today there are well over 5,000 scientific publications according to Google Scholar. Malvern recently published a book “Nanoparticle Tracking Analysis – A review of the first 1,000 reports of applications and usage of NTA“ which discusses the technology and the applications to which it has been applied.

The fields to which NTA instruments have been applied are wide ranging:

1. Protein aggregation with Nanoparticle Tracking Analysis

Protein aggregation can occur during biological manufacturing processes:

• Cell culture
• Purification
• Formulation
• Packing and storage

NTA instruments offer an advantage in identification of protein aggregation with a quick, accurate sampling process.

2. Toxicology reporting with NTA Analysis

Biological responses to nanoparticles and their flow on health implications are influenced by the particle size, concentration, and aggregation. Even particles that aren’t toxic on their own could become toxic through absorption of proteins.

3. Ecotoxicology nanomaterial identification

NTA instrument success in measuring the particle size, distribution, and concentration of engineered nanoparticles in the natural environment makes ecotoxicology a key area of use for Nanoparticle Tracking Analysis.

4. Targeted drug delivery research

The distribution of nanoparticle size is key to design and manufacture of targeted drug delivery. With the help of NTA instruments, innovative vaccines made from polymeric nanoparticles, exosomes and liposomes are being developed using:

• Conventional injection methods
• Needle free administration (transcutaneous and intranasal)

Size and distribution of nanoparticles in these medicines directly affects:

• Cell uptake of drug delivery within the immune system
• Release of vaccine components
• Skin diffusion
• Immune response

5. Virology identification and research

It’s not just in drug delivery where NTA instruments are useful. Knowing the particle size distribution of viruses and bacteriophage is essential in research and development of vaccines. An NTA reading can provide total viral count, allowing the scientist to better understand the ratio between infectious and noninfectious viruses within the preparation.

Differences between Nanoparticle Tracking Analysis and Dynamic Light Scattering

While both Dynamic Light Scattering (DLS) and NTA follow the Brownian motion of dispersed light from the target particles, they operate in different ways.

DLS works by measuring changes in the intensity of scattered light on a bulk sample. NTA measures individual particle diffusion, particle by particle. Both methods offer a number of different benefits and therefore by combining the two techniques users can take advantage of the complementary information they provide.

• NTA can often provide higher resolution size measurements, but DLS can offer a faster assessment of the mean size and polydispersity. For perfectly monodisperse samples both DLS and NTA should give the same result.
• DLS is most suitable for particle sizes larger than ~micron, for quality control of nanoparticle production and for early detection of aggregates.
• NTA is most suited for polydisperse distributions where users require a higher resolution of peaks and want to measure the concentration of nanoparticles.
• For NTA, users can selectively look at only a fluorescently tagged part of the distribution, while in DLS this is not possible and fluorescence may make measurements more difficult or even impossible (e.g. quantum dots).
• NTA can detect samples 10-1000 times more dilute than DLS.
• DLS ensemble averages the signal from at least 2-4 orders of magnitude more particles than NTA. DLS can handle a wider concentration range without dilution.

Accurate identification of nanomaterials

NTA instruments are essential in nanoparticle analysis. The Malvern NanoSight NS300 provides excellent high resolution size distribution and concentration measurements, as well as differentiation of fluorescing particles in fluorescence mode. Read more about the Malvern NanoSight NS300 and make a product enquiry today by contacting ATA Scientific.