Viral vector stability & storage assessment with NanoSight Pro

Introduction 

One of the primary goals in formulation development is to achieve a high titer with excellent product stability. However, performing titer analysis using traditional bioassays is challenging and time-consuming. This application note demonstrates how NanoSight Pro, utilizing Nanoparticle Tracking Analysis (NTA) technology, with its fast measurement capabilities and minimal sample preparation, can effectively assess formulation stability over time.

Lentivirus fragility

This study demonstrates the application of NanoSight Pro to characterize the stability of a lentivirus* formulation. The lentivirus samples were diluted in PBS buffer to the optimal concentration for NTA analysis and analyzed with a NanoSight Pro equipped with a 488 nm laser. The NanoSight Pro provides rapid size and concentration measurements, completing the process in less than 5 minutes. 

The lentivirus formulations were assessed directly after production (Figure 1 - blue line), after thawing from -80°C storage (orange line), and after three hours at room temperature (purple line) (Fig. 1). Both time and storage conditions significantly impacted the viral vector titer, which was reduced by 30% during -80°C storage and by 57% after three hours at room temperature (Table 1). Storage at -80°C caused vector aggregation, seen in an increased number of particles larger than 200 nm and clearly visible in the NanoSight Pro image (Figure 2 insert in purple frame and Table 1). Exposure to room temperature demonstrated temperature-induced destabilization of the lentivirus, which is clearly seen in the NanoSight Pro image (Fig 2 insert in orange frame and Table 1). 

Figure 1: Showing the effects of storage conditions on lentivirus stability

Table 1: Summary of size and concentration (titer) for lentivirus samples: fresh formulation, after 3 hours storage at room temperature, and after storage in -80°C

Conclusions 

NanoSight Pro is a powerful tool for fast screening of viral vector size and titer, providing real-time insights into formulation stability and the effect of storage conditions in minutes. 

Further reading 

This application is part of a five-part series. Explore the rest of the series to dive deeper into this topic: 

• Quick viral vector purity assessment with NanoSight Pro 
• Identify viral vectors with NanoSight F-NTA
• Identify VSV-G positive lentivirus with NanoSight F-NTA

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*Lentivirus samples along with formulation buffers were kindly supplied by one of Malvern Panalytical’ s collaborators.