Measuring the Particle Size and Concentration of Adeno-Associated Virus using Nanoparticle Tracking Analysis

Description a novel method to rapidly measure the size and concentration of Adeno-Associated Virus using Nanoparticle Tracking Analysis.

Abstract

In this application note, we describe a novel method to rapidly measure the size and concentration of Adeno-Associated Virus (AAV), utilizing the Nanoparticle Tracking Analysis (NTA) technique and a gold labeling method.  By labeling AAV capsids with small gold nanoparticles, we could increase the amount of light scattered by each capsid, enabling rapid NTA characterization to determine the virus concentration and aggregation state.  NTA characterization of AAV was previously impossible without gold labeling.

Introduction

In this application note, we describe a novel method to rapidly measure the size and concentration of Adeno-Associated Virus (AAV) utilizing the Nanoparticle Tracking Analysis (NTA) technique and a gold labeling method. By labeling AAV capsids with small gold nanoparticles, we were able to increase the amount of light scattered by each capsid, enabling rapid NTA characterization to determine the virus titer and aggregation state. NTA characterization of AAV was previously impossible without gold labeling. This method should be applicable to other virus types, assuming the surface chemistry is similar.

This new technique extends the benefits of simultaneous size and concentration measurements, both as an alternative or a supplement to traditional titer assays and as a check of aggregation state. The differing stability of various formulations may have a significant effect on final product performance but may not be adequately measured with current and traditional techniques.