Figure 4.

Analysis of AAV2/9 Vectors via Negative-Stain Transmission Electron Microscopy

Representative images were captured at different positions on the grid. (A) AAV293 IGC particles with a full-to-empty ratio of 5.2, (B) HEKExpress IGC particles with a full-to-empty ratio of 1.4, (C) AAV293 IAC particles with a full-to-empty ratio of 0.3, and (D) HEKExpress IAC particles with a full-to-empty ratio of 0.1. One exemplary empty particle is highlighted by the red circle. Empty particles can be distinguished based on the accumulation of stain in the particle center. The black arrow indicates impurities found exclusively in preparations derived from gradient ultracentrifugation (identified by previous studies as ferritin¹¹). The white arrow highlights impurities that we found only in the AAV293 IGC preparation, which also appeared to contain the highest amount of impurities for the SDS-PAGE analysis.