The high programmability of DNA origami has provided tools for precise manipulation of matter at the nanoscale. This manipulation of matter opens up the possibility to arrange functional elements for ...a diverse range of applications that utilize the nanometer precision provided by these structures. However, the realization of functionalized DNA origami still suffers from imperfect production methods, in particular in the purification step, where excess material is separated from the desired functionalized DNA origami. In this article we demonstrate and optimize two purification methods that have not previously been applied to DNA origami. In addition, we provide a systematic study comparing the purification efficacy of these and five other commonly used purification methods. Three types of functionalized DNA origami were used as model systems in this study. DNA origami was patterned with either small molecules, antibodies, or larger proteins. With the results of our work we aim to provide a guideline in quality fabrication of various types of functionalized DNA origami and to provide a route for scalable production of these promising tools.
The spatial organization of membrane-bound ligands is thought to regulate receptor-mediated signaling. However, direct regulation of receptor function by nanoscale distribution of ligands has not yet ...been demonstrated, to our knowledge. We developed rationally designed DNA origami nanostructures modified with ligands at well-defined positions. Using these 'nanocalipers' to present ephrin ligands, we showed that the nanoscale spacing of ephrin-A5 directs the levels of EphA2 receptor activation in human breast cancer cells. Furthermore, we found that the nanoscale distribution of ephrin-A5 regulates the invasive properties of breast cancer cells. Our ligand nanocaliper approach has the potential to provide insight into the roles of ligand nanoscale spatial distribution in membrane receptor-mediated signaling.
Linear actuators are ubiquitous components at all scales of engineering. DNA nanotechnology offers a unique opportunity for bottom‐up assembly at the molecular scale, providing nanoscale precision ...with multiple methods for constructing and operating devices. In this paper, DNA origami linear actuators with up to 200 nm travel, based on a rail threading a topologically locked slider, are demonstrated. Two strategies, one‐ and two‐pot assembly, are demonstrated whereby the two components are folded from one or two DNA scaffold strands, respectively. In order to control the position of the slider on the rail, the rail and the inside of the slider are decorated with single‐stranded oligonucleotides with distinct sequences. Two positioning strategies, based on diffusion and capture of signaling strands, are used to link the slider reversibly to determined positions on the rail with high yield and precision. These machine components provide a basis for applications in molecular machinery and nanoscale manufacture including programmed chemical synthesis.
DNA origami linear actuators are promising components of nanoscale machinery but remain difficult to assemble and control. This paper explores different routes for assembly and control, achieving a high device yield and reversible actuator positioning. Simulation shows that these devices are capable of few‐nanometer precision, opening up potential uses in molecular machinery and nanoscale manufacture.
The use of DNA as a nanoscale construction material has been a rapidly developing field since the 1980s, in particular since the introduction of scaffolded DNA origami in 2006. Although software is ...available for DNA origami design, the user is generally limited to architectures where finding the scaffold path through the object is trivial. Herein, we demonstrate the automated conversion of arbitrary two‐dimensional sheets in the form of digital meshes into scaffolded DNA nanostructures. We investigate the properties of DNA meshes based on three different internal frameworks in standard folding buffer and physiological salt buffers. We then employ the triangulated internal framework and produce four 2D structures with complex outlines and internal features. We demonstrate that this highly automated technique is capable of producing complex DNA nanostructures that fold with high yield to their programmed configurations, covering around 70 % more surface area than classic origami flat sheets.
Flat‐sheet DNA nanostructures: Using algorithmic tools, DNA nanostructures were designed from 2D meshes with varying internal geometries. Using this method, structures with complex internal and external features were prepared that self‐assemble under physiological salt concentrations and have larger surface areas compared to classic DNA origami flat‐sheet designs.
...secularism "made itself felt in the competition between religions and between . . . denominations" (7). Various religious traditions are well represented, from Christian Orthodoxy, Catholicism, ...and Protestantism (including evangelicalism) to Islam and Judaism. ...while some pieces focus on a specific nation, others have a regional or global scope. ...the essays do provide a wealth of information and insight.
It was suggested more than thirty years ago that Watson-Crick base pairing might be used for the rational design of nanometre-scale structures from nucleic acids. Since then, and especially since the ...introduction of the origami technique, DNA nanotechnology has enabled increasingly more complex structures. But although general approaches for creating DNA origami polygonal meshes and design software are available, there are still important constraints arising from DNA geometry and sense/antisense pairing, necessitating some manual adjustment during the design process. Here we present a general method of folding arbitrary polygonal digital meshes in DNA that readily produces structures that would be very difficult to realize using previous approaches. The design process is highly automated, using a routeing algorithm based on graph theory and a relaxation simulation that traces scaffold strands through the target structures. Moreover, unlike conventional origami designs built from close-packed helices, our structures have a more open conformation with one helix per edge and are therefore stable under the ionic conditions usually used in biological assays.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
...as the world became smaller, and the resulting changes disconnected many people from long-held associations (such as the nation), they would seek to reaffirm their identity in other ways. ......Huntington asserted that civilizations should not involve themselves in the internal conflicts of others. In sum, history has proven Huntington generally right, and it would be wise to follow his prescriptions for managing potential conflicts. ...a Christian perspective on international politics ought to include a commitment to order as well as justice. ...Hoffmann concludes, the best policy option for the West at this time is to respect Russian sovereignty and rely on diplomacy to defend existing democracies and promote democratic values.
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