DNA Tetrahedra as Functional Nanostructures: From Basic Principles to Applications

Self-assembled supramolecular DNA tetrahedra composed of programmed sequence-engineered complementary base-paired strands represent elusive nanostructures having key contributions to the development and diverse applications of DNA nanotechnology. By appropriate engineering of the strands, DNA tetrahedra of tuneable sizes and chemical functionalities were designed. Programmed functionalities for diverse applications were integrated into tetrahedra structures including sequence-specific recognition strands (aptamers), catalytic DNAzymes, nanoparticles, proteins, or fluorophore. The article presents a comprehensive review addressing methods to assemble and characterize the DNA tetrahedra nanostructures, and diverse applications of DNA tetrahedra framework are discussed. Topics being addressed include the application of structurally functionalized DNA tetrahedra nanostructure for the assembly of diverse optical or electrochemical sensing platforms and functionalized intracellular sensing and imaging modules. In addition, the triggered reconfiguration of DNA tetrahedra nanostructures and dynamic networks and circuits emulating biological transformations are introduced. Moreover, the functionalization of DNA tetrahedra frameworks with nanoparticles provides building units for the assembly of optical devices and for the programmed crystallization of nanoparticle superlattices. Finally, diverse applications of DNA tetrahedra in the field of nanomedicine are addressed. These include the DNA tetrahedra-assisted permeation of nanocarriers into cells for imaging, controlled drug release, active chemodynamic/photodynamic treatment of target tissues, and regenerative medicine.

DNA-Based Conductors: From Materials Design to Ultra-Scaled Electronics

Photolithography has been the foundational fabrication paradigm in current high-performance electronics. However, due to the limitation in fabrication resolution, scaling beyond a 20-nm critical dimension for metal conductors presents a significant challenge for photolithography. Structural DNA nanotechnology emerges as a promising alternative to photolithography, allowing for the site-specific assembly of nano-materials at single-molecule resolution. Substantial progresses have been achieved in the ultra-scaled DNA-based conductors, exhibiting novel transport characteristics and small critical dimensions. This review highlights the structure-transport property relationship for various DNA-based conductors and their potential applications in quantum /semiconductor electronics, going beyond the conventional scope focusing mainly on the shape diversity of DNA-templated metals. Different material synthesis methods and their morphological impacts on the conductivities are discussed in detail, with particular emphasis on the conducting mechanisms, such as insulating, metallic conducting, quantum tunneling, and superconducting. Furthermore, the ionic gating effect of self-assembled DNA structures in electrolyte solutions is examined. This review also suggests potential solutions to address current challenges in DNA-based conductors, encouraging multi-disciplinary collaborations for the future development of this exciting area.

Recent Advances in DNA Origami-Engineered Nanomaterials and Applications

DNA nanotechnology is a unique field, where physics, chemistry, biology, mathematics, engineering, and materials science can elegantly converge. Since the original proposal of Nadrian Seeman, significant advances have been achieved in the past four decades. During this glory time, the DNA origami technique developed by Paul Rothemund further pushed the field forward with a vigorous momentum, fostering a plethora of concepts, models, methodologies, and applications that were not thought of before. This review focuses on the recent progress in DNA origami-engineered nanomaterials in the past five years, outlining the exciting achievements as well as the unexplored research avenues. We believe that the spirit and assets that Seeman left for scientists will continue to bring interdisciplinary innovations and useful applications to this field in the next decade.

Intelligent Programmable DNA Nanomachines for the Spatially Controllable Imaging of Intracellular MicroRNA

The high programmability of DNA molecules makes them particularly suitable for constructing artificial molecular machines to perform sophisticated functions by simulating complex living systems. However, intelligent DNA nanomachines which can perform precise tasks logically in complex environments still remain challenging. Herein, we develop a general strategy to design a pH-responsive programmable DNA (PRPD) nanomachine to perform multilayer DNA cascades, enabling precise sensing and calculation of intracellular biomolecules. The PRPD nanomachine is built on a four-stranded DNAzyme walker precursor with a DNA switch on the surface of an Au nanoparticle, which is capable of precisely responding to pH variations in living cells by sequence tuning. This multilayer DNA cascade networks have been applicated in spatially controlled imaging of intracellular microRNA, which efficiently avoided the DNA nanomachine activated by nonspecific extracellular molecules and achieved apparent signal amplification. Our strategy enables the sensing-computing-output functional integration of DNA nanomachines, facilitating the application of programmable and complex nanomachines in nanoengineering, chemistry, and biomedicine.

DNA-Mediated Assembly of Carbon Nanomaterials

Carbon nanomaterials (CNMs) have attracted extensive attentions on account of their superior electrical, mechanical, optical, and biological properties. However, the dimensional limit and irregular arrangement have hampered their further application. It is necessary to find an easy, efficient and controllable way to assemble CNMs into well-ordered array. DNA nanotechnology, owning to the advantages of precise programmability, highly structural predictability and spatial addressability, has been widely applied in the assembly of CNMs. Summarizing the progress and achievements in this field will be of great value to related studies. Herein, based on the different dimensions of CNMs containing 0-dimensional (0D) carbon dots (CDs), fullerenes, 1-dimensional (1D) carbon nanotubes (CNTs) and 2-dimensional (2D) graphene, we introduced the conjugation strategies between DNA and CNMs, their different assembly methods and their applications. In addition, we also discuss the existing challenges and future opportunities in the field.

DNA Framework-Mediated Geometric Renormalization of Gold Nanoparticles on a Two-Dimensional Fluidic Membrane Interface

The precise arrangement of single entity is a crucial objective of nanoscience and holds great promise in various fields such as biology and material science. In this work, we develop a "DNA framework-mediated geometric renormalization" (DFMGR) strategy to reassemble gold nanoparticles into specific geometric shapes on a 2-dimensional (2D) fluidic membrane interface. Cholesterol-modified AuNPs are randomly anchored on the supported lipid bilayer (SLB) via the cholesterol-lipid interaction. We demonstrate that AuNPs are laterally mobile on SLB and could be further rearranged into a specific geometric shape by DNA framework containing algebraically topological DNA arms. Using scanning electron microscope (SEM) imaging approach, simple geometric shapes, such as points assembled by monomers, line segments assembled by dimers, triangles assembled by trimers are visually presented. Interestingly, we found that the statistic angle (58.77°) and side length (12.21 nm) of triangles obtained from SEM images were both agreed well with the theoretical angle of 60° and side length of 12.58 nm. And the relative error of the angle calculated was as low as 0.33 %. These results indicated that the DFMGR strategy showed precise regulation ability for the AuNPs renormalization. We believe that DNA framework-mediated geometric renormalization strategy would be a powerful means for regulating ligand-receptor interactions in biosystems and for nanoparticle assembling in material science.