Spatiotemporal Control of Molecular Cascade Reactions by a Reconfigurable DNA Origami Domino Array

Self-assembled methodologies for the construction of DNA nanostructures and biological applications

Over the past decades, deoxyribonucleic acid (DNA), as a versatile building block, has been widely employed to construct functionalized nanostructures. Among the diverse types of materials, DNA related nanostructures have gained growing attention due to their intrinsic programmability, favorable biocompatibility, and strong molecular recognition capability. The conventional construction strategy for building DNA structures is based on Watson-Crick base-pairing rules, which are mainly driven by the hydrogen bonding of bases. However, hydrogen bonding-based DNA nanostructures cannot meet the requirements of specific morphology and multifunctionality. Currently, various functional elements have been introduced to expand the synthetic methodologies for constructing the DNA hybrid nanostructures, including small molecules, peptide polymers, organic ligands and transition metal ions. Besides, the potential applications for these DNA hybrid nanostructures have also been explored. It has been demonstrated that DNA hybrid structures with various properties can be extensively applied in the fields of magnetic resonance, luminescence imaging, biomedical detection, and drug delivery systems. In this review, we highlight the pioneering contributions to the methodologies of DNA-based nanostructure assembly. Furthermore, the recent advances in drug delivery systems and biomedical diagnosis based on DNA hybrid nanostructures are briefly summarized.

Biomolecule-Driven Two-Factor Authentication Strategy for Access Control of Molecular Devices

The rise of DNA nanotechnology is promoting the development of molecular security devices and marking an essential change in information security technology, to one that can resist the threats resulting from the increase in computing power, brute force attempts, and quantum computing. However, developing a secure and reliable access control strategy to guarantee the confidentiality of molecular security devices is still a challenge. Here, a biomolecule-driven two-factor authentication strategy for access control of molecular devices is developed. Importantly, the two-factor is realized by applying the specificity and nicking properties of the nicking enzyme and the programmable design of the DNA sequence, endowing it with the characteristic of a one-time password. To demonstrate the feasibility of this strategy, an access control module is designed and integrated to further construct a role-based molecular access control device. By constructing a command library composed of three commands (Ca, Cb, Ca and Cb), the authorized access of three roles in the molecular device is realized, in which the command Ca corresponds to the authorization of role A, Cb corresponds to the authorization of role B, and Ca and Cb corresponds to the authorization of role C. In this way, when users access the device, they not only need the correct factor but also need to apply for role authorization in advance to obtain secret information. This strategy provides a highly robust method for the research on access control of molecular devices and lays the foundation for research on the next generation of information security.

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.

Small Molecule-Templated DNA Hydrogel with Record Stiffness Integrates and Releases DNA Nanostructures and Gene Silencing Nucleic Acids

Deoxyribonucleic acid (DNA) hydrogels are a unique class of programmable, biocompatible materials able to respond to complex stimuli, making them valuable in drug delivery, analyte detection, cell growth, and shape-memory materials. However, unmodified DNA hydrogels in the literature are very soft, rarely reaching a storage modulus of 10³  Pa, and they lack functionality, limiting their applications. Here, a DNA/small-molecule motif to create stiff hydrogels from unmodified DNA, reaching 10⁵  Pa in storage modulus is used. The motif consists of an interaction between polyadenine and cyanuric acid-which has 3-thymine like faces-into multimicrometer supramolecular fibers. The mechanical properties of these hydrogels are readily tuned, they are self-healing and thixotropic. They integrate a high density of small, nontoxic molecules, and are functionalized simply by varying the molecule sidechain. They respond to three independent stimuli, including a small molecule stimulus. These stimuli are used to integrate and release DNA wireframe and DNA origami nanostructures within the hydrogel. The hydrogel is applied as an injectable delivery vector, releasing an antisense oligonucleotide in cells, and increasing its gene silencing efficacy. This work provides tunable, stimuli-responsive, exceptionally stiff all-DNA hydrogels from simple sequences, extending these materials' capabilities.

Self-Assembled Artificial DNA Nanocompartments and Their Bioapplications

Compartmentalization is the strategy evolved by nature to control reactions in space and time. The ability to emulate this strategy through synthetic compartmentalization systems has rapidly evolved in the past years, accompanied by an increasing understanding of the effects of spatial confinement on the thermodynamic and kinetic properties of the guest molecules. DNA nanotechnology has played a pivotal role in this scientific endeavor and is still one of the most promising approaches for the construction of nanocompartments with programmable structural features and nanometer-scaled addressability. In this review, the design approaches, bioapplications, and theoretical frameworks of self-assembled DNA nanocompartments are surveyed. From DNA polyhedral cages to virus-like capsules, the construction principles of such intriguing architectures are illustrated. Various applications of DNA nanocompartments, including their use for programmable enzyme scaffolding, single-molecule studies, biosensing, and as artificial nanofactories, ending with an ample description of DNA nanocages for biomedical purposes, are then reported. Finally, the theoretical hypotheses that make DNA nanocompartments, and nanosystems in general, a topic of great interest in modern science, are described and the progresses that have been done until now in the comprehension of the peculiar phenomena that occur within nanosized environments are summarized.

Selectivity of natural isoquinoline alkaloid assembler in programming poly(dA) into parallel duplex by polyvalent synergy

Ligand-induced assembly of disordered DNAs attracts much attention due to its potential action in transcription regulation and molecular switches-based sensors. Among natural isoquinoline alkaloids (NIAs), we screened out nitidine (NIT) as polyvalent-binding assembler to program poly(dA) into a parallel duplex assembly at neutral pH. The molecule planarity of NIAs was believed to be a determinant factor in programming the parallel poly(dA) assembly. Poly(dA) with more than six adenines can initiate the synergistic binding of NIT to generate the parallel assembly. It is expected that one A-A pair in duplex can bind one NIT molecule provided that poly(dA) is long enough, suggesting the pivotal role of the polyvalent synergy of NIT in programming the parallel poly(dA) assembly. A gold nanoparticles-based colorimetric method was also developed to screen NIT out of NIAs having the potential to construct the poly(dA) assembly. Our work will inspire more interest in developing polyadenine-based switches and sensors by concentrating NIT within the polyadenine parallel assembly.

Active Self-Assembly of Ladder-Shaped DNA Carrier for Drug Delivery

With the advent of nanotechnology, DNA molecules have been transformed from solely genetic information carriers to multifunctional materials, showing a tremendous potential for drug delivery and disease diagnosis. In drug delivery systems, DNA is used as a building material to construct drug carriers through a variety of DNA self-assembly methods, which can integrate multiple functions to complete in vivo and in situ tasks. In this study, ladder-shaped drug carriers are developed for drug delivery on the basis of a DNA nanoladder. We first demonstrate the overall structure of the nanoladder, in which a nick is added into each rung of the nanoladder to endow the nanoladder with the ability to incorporate a drug loading site. The structure is designed to counteract the decrement of stability caused by the nick and investigated in different conditions to gain insight into the properties of the nicked DNA nanoladders. As a proof of concept, we fix the biotin in every other nick as a loading site and assemble the protein (streptavidin) on the loading site to demonstrate the feasibility of the drug-carrying function. The protein can be fixed stably and can be extended to different biological and chemical drugs by altering the drug loading site. We believe this design approach will be a novel addition to the toolbox of DNA nanotechnology, and it will be useful for versatile applications such as in bioimaging, biosensing, and targeted therapy.