We recently published our application note, “Adeno-Associated Virus titer and aggregation characterization“, which discusses a new NanoSight method that allows the visualization and therefore analysis of viruses smaller than what was previously possible to measure.  This represents an exciting extension of the Nanoparticle Tracking Analysis (NTA) technique in response to market demand for tools for better characterization of small virus types.

Adeno-Associated Virus (AAV) is commonly used in the gene therapy field as a delivery vector. Tools to characterize both the concentration and purity or aggregation of the samples are limited because the primary virus size is approximately 25 nm, well below the limit of detection for a number of techniques used with larger virus types.

The technique involves the labeling of the virus capsid with a number of small gold nanoparticles.  This results in the labeled virus being able to scatter much more light than a bare virus, making it visible to NanoSight instruments.  While this method does not follow the label-free approach of most other NTA applications, it is quite straightforward and still makes for a fast and robust analytical method.  It is thought that this gold-labeling technique will be applicable to a number of other virus types, in addition to AAV.

Information derived via this method for AAV and other virus types includes total viral concentration or titer, as well as size distribution, which can inform us about the relative purity or aggregation state. Our application note on “Total viral titer in minutes” is a good review of the information delivered by viral studies using NTA, and where the technology finds use in this application space.

This development is a good example of the standard of the technical team within Malvern Instruments and the development efforts that go into providing valuable characterization tools and techniques for research. It is heartwarming to know that we are contributing to the advancement of such important science.

A webinar with more details of the technique is planned for the 7th June, this webinar will focus on “Adeno-Associated Viral Titer in minutes, using Nanoparticle Tracking Analysis“.