The modification of the backbone properties of DNA origami nanostructures through noncovalent interactions with designed intercalators, based on acridine derivatized with side chains containing esterified fatty acids or oligo(ethylene glycol) residues is reported. Spectroscopic analyses indicate that these intercalators bind to DNA origami structures. Atomic force microscopy studies reveal that intercalator binding does not affect the structural intactness but leads to altered surface properties of the highly negatively charged nanostructures, as demonstrated by their interaction with solid mica or graphite supports. Moreover, the noncovalent interaction between the intercalators and the origami structures leads to alteration in cellular uptake, as shown by confocal microscopy studies using two different eukaryotic cell lines. Hence, the intercalator approach offers a potential means for tailoring the surface properties of DNA nanostructures.

This work describes the synthesis of amino-reactive, photocleavable hapten-modifiers and their application as affinity tags for DNA nanostructures. In particular, N-hydroxysuccinimide-activated linkers containing an α-methyl-nitroveratryl-butyric acid group and carboxyfluorescein or biotin were synthesized and coupled to alkyl-amino-modified DNA oligonucleotides. The resulting conjugates were then incorporated into DNA origami nanostructures. As demonstrated by electrophoresis and AFM imaging, the functionalized nanostructures were capable to bind cognate proteins which could then be cleaved-off by irradiation. Owing to its modularity, this approach to control protein binding should be useful for a wide variety of functional DNA nanostructures.

Arrays of biomimetic lipid patches for studying the binding of DNA origami structures can be tailored in size, shape, and composition with the aid of lipid-dip pen nanolithography. This approach allows for analysis of the effects of lipid composition with high throughput which could be applied for the targeted presentation of functional DNA origami structures on surfaces.