Adeno-associated viral vectors

Adeno-associated virus (AAV)-based gene therapies have shown great promise in clinical trials, offering hope for treating a variety of genetic disorders. The potency and safety of these therapies depends, among many factors, on the percentages of full, partially filled and empty capsids, critical quality attributes which can be clearly evaluated 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.