Gene-encoding DNA origami for mammalian cell expression

DNA origami may enable more versatile gene delivery applications through its ability to create custom nanoscale objects with specific targeting, cell-invading, and intracellular effector functionalities. Toward this goal here we describe the expression of genes folded in DNA origami objects delivered to mammalian cells. Genes readily express from custom-sequence single-strand scaffolds folded within DNA origami objects, provided that the objects can denature in the cell. We demonstrate enhanced gene expression efficiency by including and tuning multiple functional sequences and structures, including virus-inspired inverted-terminal repeat-like (ITR) hairpin motifs upstream or flanking the expression cassette. We describe gene-encoding DNA origami bricks that assemble into multimeric objects to enable stoichiometrically controlled co-delivery and expression of multiple genes in the same cells. Our work provides a framework for exploiting DNA origami for gene delivery applications.