Single-Particle Tracking and Modulation of Cell Entry Pathways of a Tetrahedral DNA Nanostructure in Live Cells

Building a chimera of aptamer–antisense oligonucleotide for silencing galectin-1 gene

Galectin-1 is closely related with immune systems, and its overexpression may cause tumor metastasis.

Molecular logic gates based on DNA tweezers responsive to multiplex restriction endonucleases

Self-assembled DNA tweezers containing four different restriction endonuclease recognition sites were designed and a set of logic gates were constructed.

Cationic sulfonium functionalization renders Znsalens with high fluorescence, good water solubility and tunable cell-permeability

Introducing cationic sulfonium to the Znsalens skeleton circumvents aggregation arising from intermolecular Zn⋯O interactions (found between Zn and the phenoxyl group of another Znsalen molecule).

Observation of intracellular interactions between DNA origami and lysosomes by the fluorescence localization method

The combined image (b) of the fluorescence localization image of DNA origami and the TIRF image of lysosomes illustrates detailed interactions between them.

Cellular processing and destinies of artificial DNA nanostructures

This review gives a panoramic view of the many DNA nanotechnology applications in cells, mechanistic understanding of how and where their interactions occur and their subsequent outcomes.

Designer DNA Architectures: Applications in Nanomedicine

DNA has been used as a material for the construction of nanoscale objects. These nanostructures are programmable and allow the conjugation of biomolecular guests to improve their functionality. DNA nanostructures display a wide variety of characteristics, such as cellular permeability, biocompatibility and stability, and responsiveness to external stimuli, making them excellent candidates for applications in nanomedicine.

Advances in Functional Assemblies for Regenerative Medicine

The ability to synthesise bioresponsive systems and selectively active biochemistries using polymer-based materials with supramolecular features has led to a surge in research interest directed towards their development as next generation biomaterials for drug delivery, medical device design and tissue engineering.

Conformational Change of Self-Assembled DNA Nanotubes Induced by Two-Photon Excitation

Two-photon-regulated, shape-changing DNA nanostructures are demonstrated by integrating a DNA nanotube with a two-photon photocleavable module that enables the opening of the cavities of tube, and becomes partially single-stranded in response to two-photon excitation under 800 nm fs laser pulses.

DNA nanotechnology from the test tube to the cell

The programmability of Watson-Crick base pairing, combined with a decrease in the cost of synthesis, has made DNA a widely used material for the assembly of molecular structures and dynamic molecular devices. Working in cell-free settings, researchers in DNA nanotechnology have been able to scale up system complexity and quantitatively characterize reaction mechanisms to an extent that is infeasible for engineered gene circuits or other cell-based technologies. However, the most intriguing applications of DNA nanotechnology - applications that best take advantage of the small size, biocompatibility and programmability of DNA-based systems - lie at the interface with biology. Here, we review recent progress in the transition of DNA nanotechnology from the test tube to the cell. We highlight key successes in the development of DNA-based imaging probes, prototypes of smart therapeutics and drug delivery systems, and explore the future challenges and opportunities for cellular DNA nanotechnology.

DNA nanotechnology-enabled biosensors

Biosensors employ biological molecules to recognize the target and utilize output elements which can translate the biorecognition event into electrical, optical or mass-sensitive signals to determine the quantities of the target. DNA-based biosensors, as a sub-field to biosensor, utilize DNA strands with short oligonucleotides as probes for target recognition. Although DNA-based biosensors have offered a promising alternative for fast, simple and cheap detection of target molecules, there still exist key challenges including poor stability and reproducibility that hinder their competition with the current gold standard for DNA assays. By exploiting the self-recognition properties of DNA molecules, researchers have dedicated to make versatile DNA nanostructures in a highly rigid, controllable and functionalized manner, which offers unprecedented opportunities for developing DNA-based biosensors. In this review, we will briefly introduce the recent advances on design and fabrication of static and dynamic DNA nanostructures, and summarize their applications for fabrication and functionalization of DNA-based biosensors.

Self-assembled multifunctional DNA nanospheres for biosensing and drug delivery into specific target cells

Self-assembly of three dimensional nucleic acid nanostructures is of great significance in nanotechnology, biosensing and biomedicine. Herein we present a novel class of multifunctional and programmable DNA nanostructures, termed nanospheres (NSs), with monodispersity, dense compaction and uniform size (∼ 200 nm) using only four DNAs based on not only Watson-Crick base pair hybridization between single-stranded DNA but also liquid crystallization and dense packing from periodic DNA duplexes. Due to the diversity of the internal structures, the present NSs can easily evolve into other kinds of DNA assemblies, such as DNA spherical structures with a larger size and a rough surface via rolling circle replication (RCR). Importantly, the functional arms incorporated in building units can be readily designed for biosensing and targeted cancer therapy with high payload capacity and excellent biocompatibility. Therefore, the proposed NSs could lead to novel routes for nucleic acid self-assembly, promising versatile applications in biosensing and biomedicine.

Local pH tracking in living cells

Continuous and simultaneous 3D single-particle movement and local pH detection in HeLa cells were demonstrated for the first time by combining fluorescent mesoporous silica nanoparticles (FMSNs) and a single-particle tracking (SPT) technique with a precision of ∼10 nm. FMSNs, synthesized by the co-condensation of both pH-sensitive and reference dyes with a silica/surfactant source, allow long-term reliable ratiometric pH measurements with a precision better than 0.3 pH unit because of their excellent brightness and stability. pH variation in the surrounding area of FMSNs during endocytosis was monitored in real-time. Acidification and low mobility of FMSNs were observed at the early endocytic stage, whereas basification and high mobility of FMSNs were observed at the late stage. Our results indicate that it is possible to monitor local pH changes in the environments surrounding nanoparticles during the cellular uptake process of FMSNs, which provides much needed information for designing an efficient drug delivery nanosystem.

Engineering DNA scaffolds for delivery of anticancer therapeutics

Engineering DNA nanostructures with programmability in size, shape and surface chemistry holds tremendous promise in biomedical applications. As an emerging platform for drug delivery, DNA nanostructures have been extensively studied for delivering anticancer therapeutics, including small-molecule drug, nucleic acids and proteins. In this mini-review, current advances in utilizing DNA scaffolds as drug carriers for cancer treatment were summarized and future challenges were also discussed.

DNA nanostructures: a shift from assembly to applications

The specificity of DNA hybridization allows for the modular design of 2D and 3D shapes with wide-ranging applications including sensors, actuators, and even logic devices. The inherent biocompatibility of DNA and the ability to produce monodisperse structures of controlled shape and size make DNA nanostructures of interest as potential drug and gene delivery vehicles. In this review, we discuss several new approaches for the assembly of DNA nanostructures, advances in the modeling of these structures, and we highlight recent studies on the use of DNA nanotechnology for therapeutic applications such as drug delivery in tumor models.

Functional DNA nanostructures for theranostic applications

There has been tremendous interest in constructing nanostructures by exploiting the unparalleled ability of DNA molecules in self-assembly. We have seen the appearance of many fantastic, "art-like" DNA nanostructures in one, two, or three dimensions during the last two decades. More recently, much attention has been directed to the use of these elegant nanoobjects for applications in a wide range of areas. Among them, diagnosis and therapy (i.e., theranostics) are of particular interest given the biological nature of DNA. One of the major barricades for the biosensor design lies in the restricted target accessibility at the solid-water interface. DNA nanotechnology provides a convenient approach to well control the biomolecule-confined surface to increase the ability of molecular recognition at the biosensing interface. For example, tetrahedral DNA nanostructures with thiol modifications can be self-assembled at the gold surface with high reproducibility. Since DNA tetrahedra are highly rigid and well-defined structures with atomic precision and versatile functionality, they provide scaffolds for anchoring of a variety of biomolecular probes (DNA, aptamers, peptides, and proteins) for biosensing. Significantly, this DNA nanostructure-based biosensing platform greatly increases target accessibility and improves the sensitivity for various types of molecular targets (DNA, RNA, proteins, and small molecules) by several orders of magnitude. In an alternative approach, DNA nanostructures provide a framework for the development of dynamic nanosensors that can function inside the cell. DNA tetrahedra are found to be facilely cell permeable and can sense and image specific molecules in cells. More importantly, these DNA nanostructures can be efficient drug delivery nanocarriers. Since they are DNA molecules by themselves, they have shown excellent cellular biocompatibility with minimal cytotoxicity. As an example, DNA tetrahedra tailored with CpG oligonucleotide drugs have shown greatly improved immunostimulatory effects that makes them a highly promising nanomedicine. By taking them together, we believe these functionalized DNA nanostructures can be a type of intelligent theranostic nanodevice for simultaneous sensing, diagnosis, and therapy inside the cell.