Optimizing the stability of a DNA origami snub cube inhibitor

With climate change threatening to increase the frequency of global pandemics, the need for quick and adaptable responses to novel viruses will become paramount. DNA nanotechnology offers a highly customizable, biocompatible approach to combating novel outbreaks. For any DNA nanotechnology-based therapeutic to have future success in vivo, the structure must be able to withstand serological conditions for an extended time period. In this study, the stability of a wireframe DNA snub cube with attached nbGFP used to bind a nonessential viral epitope on Pseudorabies virus is evaluated in vitro both with and without one of two modifications designed to enhance stability: 1) the use of trivalent spermidine cations during thermal annealing of the nanostructure, and 2) the introduction of a polylysine-polyethylene glycol coating to the conjugated nanostructure. The design, synthesis, and purification of the multivalent inhibitor were also evaluated and optimized. Without modification, the snub cube nanostructure was stable for up to 8 hours in culture media supplemented with 10% FBS. The spermidine-annealed nanostructures demonstrated lesser degrees of stability and greater degradation than the unmodified structures, whereas the polylysine-coated structures demonstrated equivalent stability at lower valencies and enhanced stability at the highest valency of the snub cube inhibitor. These results support the potential for the polylysine-polyethylene glycol coating as a potential method for enhancing the stability of the snub cube for future in vivo applications.