Increased anticoagulant activity of thrombin-binding DNA aptamers by nanoscale organization on DNA nanostructures.

Control over thrombin activity is much desired to regulate blood clotting in surgical and therapeutic situations. Thrombin-binding RNA and DNA aptamers have been used to inhibit thrombin activity and thus the coagulation cascade. Soluble DNA aptamers, as well as two different aptamers tethered by a flexible single-strand linker, have been shown to possess anticoagulant activity. Here, we link multiple aptamers at programmed positions on DNA nanostructures to optimize spacing and orientation of the aptamers and thereby to maximize anticoagulant activity in functional assays. By judicious engineering of the DNA nanostructures, we have created a novel, functional DNA nanostructure, which is a multi-aptamer inhibitor with activity eightfold higher than free aptamer. Reversal of the thrombin inhibition was also achieved by the use of single-stranded DNA antidotes, thus enabling significant control over blood coagulation. FROM THE CLINICAL EDITOR: Thrombin inhibition via DNA aptamers has recently become a possibility. In this study, thrombin-binding DNA aptamers were further optimized by nanoscale organization on DNA nanostructures. The authors have created a novel, functional DNA nanostructure, which is a multi-aptamer inhibitor with activity eightfold higher than that of free aptamer. Reversal of thrombin inhibition was also achieved by single-stranded DNA antidotes, enabling significant control over the coagulation pathway.

Weave tile architecture construction strategy for DNA nanotechnology.

Architectural designs for DNA nanostructures typically fall within one of two broad categories: tile-based designs (assembled from chemically synthesized oligonucleotides) and origami designs (woven structures employing a biological scaffold strand and synthetic staple strands). Both previous designs typically contain many Holliday-type multi-arm junctions. Here we describe the design, implementation, and testing of a unique architectural strategy incorporating some aspects of each of the two previous design categories but without multi-arm junction motifs. Goals for the new design were to use only chemically synthesized DNA, to minimize the number of component strands, and to mimic the back-and-forth, woven strand routing of the origami architectures. The resulting architectural strategy employs "weave tiles" formed from only two oligonucleotides as basic building blocks, thus decreasing the burden of matching multiple strand stoichiometries compared to previous tile-based architectures and resulting in a structurally flexible tile. As an example application, we have shown that the four-helix weave tile can be used to increase the anticoagulant activity of thrombin-binding aptamers in vitro.