Site-Specific Disulfide-Mediated Crosslinking of DNA Nanocubes for Enhanced Biological Applications

The development of DNA nanotechnology has enabled the creation of diverse nanomaterials with significant potential in biological applications, such as sensing or drug delivery. From DNA origami to wireframe nanostructures, several strategies have been developed to deliver nucleic acid therapeutics into cells. However, these self-assembled structures suffer from poor stability in biological media due to low concentrations of divalent cations, degradation by nucleases, and thermal denaturation. Herein, a site-specific crosslinking method based on thiol-disulfide exchange to stabilize a wireframe DNA nanocube is developed. With nearly quantitative crosslinking yields, the structure retains its structural integrity in conditions that mimic physiological environments. This results in improved cellular uptake, likely due to more favorable interaction with cell-surface scavenger receptors, followed by endocytosis. This study paves the way for in vivo applications of DNA wireframe nanostructures by removing one of the major bottlenecks for their translation from in vitro to preclinical work.