Adeno-associated virus (AAV) characterization

AAV characterization is critical to gene therapy development: adeno-associated virus (AAV)-based therapies have shown great promise in clinical trials, but their potency and safety depend, among other factors, on the percentages of full, partially filled and empty capsids. These are critical quality attributes that can be clearly resolved using cryogenic transmission electron microscopy (cryoTEM).

By visualizing each AAV particle, TEM can differentiate between fully filled, partially filled, and empty particles, which is crucial information for understanding treatment efficacy and immunogenicity. Compared to orthogonal methods, TEM analysis is relatively unaffected by the presence of proteins, debris, and aggregation, allowing for accurate particle classification and ratio calculations.