NTA analysis is a technique capable of sizing and quantifying nanoparticles through the use of light scattering. Unlike traditional dynamic light scattering, a CCD camera is used to track the movement of individual nanoparticles in real time, and the system derives their hydrodynamic radius through the Stokes-Einstein equation. Nanosight also goes beyond DLS in that it explicitly quantifies particles below 1 micron and can more accurately characterize polydisperse samples.
The importance of characterizing particles in the nanoparticle range was recently highlighted in a publication from CDER in which NTA was used to evaluate differences in erythropoietin peptide mimetic products which were associated with severe adverse postmarketing events (Kotarek et.al, J. Pharm.Sci. 2016, 1-5). The particle core recommends NTA to complement MFI analysis and bridge the gap below 1 micron for particle characterization and enumeration.Nanosight would be a valuable technique to monitor monomer and aggregation formation in the ≤ 1 micron size range.
For proteinaceous particles, NTA has proven to be useful to characterize and quantify particles down to 50 nm in size. The optimal concentration range for NTA is 106 to 109 particles/mL.