Nanoparticle Tracking Analysis
Nanoparticle Tracking Analysis (NTA), also known as Particle Tracking Analysis (PTA), is a high-resolution particle size analysis on the sub-micron scale. Analysis is conducted on an aqueously suspended, sub-micron material using the same theory as Dynamic Light Scattering (DLS); however, NTA is more resolute and counts individual particles to construct a particle size distribution. The suspended sub-micron material is infused through a cell with a laser passing through it. The light passing through the cell is scattered by the suspended material. Videos of the scattered light are captured by the instrument, which are then used to determine the hydrodynamic spherical equivalent diameter based on the Brownian motion of each particle. Due to the high resolution of the instrument, the final results can be presented in several ways, but are standardly presented with the number-weighted mean, mode, standard deviation, and relative concentration.
Particle Size by NTA is recognized by numerous standards and guidance agencies, including the ISO, ASTM, and EFSA. This technique’s focus on sub-micron material makes it a good choice for evaluating nanomaterials. More specifically, the high-resolution nature of the technique allows for better characterization of broad distributions and/or low concentration samples. The counting capability of the instrument allows for comparison of sub-micron concentrations between lots or evaluation of a low quantity of nanomaterial (safety/cleanliness testing).
A wide variety of sample types can be analyzed by NTA, including active pharmaceuticals (APIs), emulsion droplets, exosomes, liposomes, virosomes, and other nanomaterials that are safety/bioavailability concerns. Common applications include QA/QC batch testing, general survey screening measurements, stability studies, spiking studies, cleanliness, safety studies, and comparative studies.
Advantages
- Higher resolution than Dynamic Light Scattering
- True particle counter – yields number-weighted distribution
- Provides concentration results; number of particles per mL of fluid
Considerations
- Only analyzes samples prepared in an aqueous suspension
- Detection range about 30 nanometers to 1 micron
- Heterogenous material cannot be distinguished
Sample Requirements
Ideal aqueous suspension sample amount is 20 mL.
For solid samples, 1 gram should be sufficient. Instructions for proper re-suspension should also be provided.
The above sample quantities are preferred. If sample availability is further limited, please contact us to share specifics about your sample and options for suitable sample quantities.
Detection Range
PTL’s Nano Department can measure particulate from approximately 30 nanometers (nm) up to 1 micron (µm) with the Nanoparticle Tracking Analysis technique.
Data Reported
A comprehensive summary including the general graphical particle size distribution on number distribution will be provided, as well as the most commonly requested parameters (10th, 50th and 90th percentiles, etc.). Information on specific sizes can be reported on request. Concentration of particle per mL is also reported.
Sample Reports
Instrumentation
Particle Technology Labs uses the Malvern NanoSight NS300 for Nanoparticle Tracking Analysis.
