DNA origami nanostructures as first presented by Rothemund have demonstrated great potential as functional platforms for various biomedical applications. Due to their broad applicability in technology and science, stability analysis of DNA origami structures is of high importance. While in the academic setting, experiments are typically performed using freshly prepared DNA origami samples, technological applications will require the storage of structurally intact DNA origami for extended periods of time. Among preservation processes, lyophilization has been discussed as a promising method for long term preservation of DNA origami structures at ambient temperatures. One drawback of this method is that it requires temperatures of down to -80 °C which may not be reached using typical lab equipment. In another work, freezing has been shown to reduce the lifetime of DNA molecules under tension.
Here, we thus investigate the durability of triangular DNA origami structures under repeated freezing and thawing using single-molecule atomic force microscopy. The DNA origami triangles maintain their structural integrity over many freezing and thawing cycles, up until a certain threshold after which the fraction of intact DNA origami is rapidly decreasing. We also evaluate the possibility to further increase this threshold by addition of cryoprotectants.