Performing DNA nanotechnology operations on a zebrafish

Lipid-linked nucleoside triphosphates for enzymatic synthesis of hydrophobic oligonucleotides with enhanced membrane anchoring efficiency

We designed and synthesized a series of 2'-deoxyribonucleoside triphosphates (dNTPs) bearing various lipid moieties. Fatty acid- and cholesterol-modified dNTPs proved to be substrates for KOD XL DNA polymerase in primer extension reactions. They were also mutually compatible for simultaneous multiple incorporations into the DNA strand. The methodology of enzymatic synthesis opened a pathway to diverse structurally unique lipid-ON probes containing one or more lipid units. We studied interactions of such probes with the plasma membranes of live cells. Employing a rational design, we found a series of lipid-ONs with enhanced membrane anchoring efficiency. The in-membrane stability of multiply modified ONs was superior to that of commonly studied ON analogues, in which a single cholesterol molecule is typically tethered to the thread end. Notably, some of the probes were detected at the cell surface even after 24 h upon removal of the probe solution. Such an effect was general to several studied cell lines.

Polydopamine-coated i-motif DNA/Gold nanoplatforms for synergistic photothermal-chemotherapy

The combination of photothermal therapy with chemotherapy has gradually developed into promising cancer therapy. Here, a synergistic photothermal-chemotherapy nanoplatform based on polydopamine (PDA)-coated gold nanoparticles (AuNPs) were facilely achieved via the in situ polymerization of dopamine (DA) on the surface of AuNPs. This nanoplatform exhibited augmented photothermal conversion efficiency and enhanced colloidal stability in comparison with uncoated PDA shell AuNPs. The i-motif DNA nanostructure was assembled on PDA-coated AuNPs, which could be transformed into a C-quadruplex structure under an acidic environment, showing a characteristic pH response. The PDA shell served as a linker between the AuNPs and the i-motif DNA nanostructure. To enhance the specific cellular uptake, the AS1411 aptamer was introduced to the DNA nanostructure employed as a targeting ligand. In addition, Dox-loaded NPs (DAu@PDA-AS141) showed the pH/photothermal-responsive release of Dox. The photothermal effect of DAu@PDA-AS141 elicited excellent photothermal performance and efficient cancer cell inhibition under 808 nm near-infrared (NIR) irradiation. Overall, these results demonstrate that the DAu@PDA-AS141 nanoplatform shows great potential in synergistic photothermal-chemotherapy.

Recent Advances in DNA-Based Cell Surface Engineering for Biological Applications

Due to its excellent programmability and biocompatibility, DNA molecule has unique advantages in cell surface engineering. Recent progresses provide a reliable and feasible way to engineer cell surfaces with diverse DNA molecules and DNA nanostructures. The abundant form of DNA nanostructures has greatly expanded the toolbox of DNA-based cell surface engineering and gave rise to a variety of novel and fascinating applications. In this review, we summarize recent advances in DNA-based cell surface engineering and its biological applications. We first introduce some widely used methods of immobilizing DNA molecules on cell surfaces and their application features. Then we discuss the approaches of employing DNA nanostructures and dynamic DNA nanotechnology as elements for creating functional cell surfaces. Finally, we review the extensive biological applications of DNA-based cell surface engineering and discuss the challenges and prospects of DNA-based cell surface engineering.

Carrier-free micellar CpG interacting with cell membrane for enhanced immunological treatment of HIV-1

Unmethylated CpG motifs activate toll-like receptor 9 (TLR9), leading to sequence- and species-specific immune stimulation. Here, we engineered a CpG oligodeoxyribonucleotide (ODN) with multiple hydrophobic moieties, so-called lipid-modified uracil, which resulted in a facile micelle formation of the stimulant. The self-assembled CpG nanostructure (U4CpG) containing the ODN 2216 sequence was characterized by various spectroscopic and microscopic methods together with molecular dynamics simulations. Next, we evaluated the nano-immunostimulant for enhancement of anti-HIV immunity. U4CpG treatment induced activation of plasmacytoid dendritic cells (pDCs) and natural killer (NK) cells in healthy human peripheral blood, which produced type I interferons (IFNs) and IFN-γ in human peripheral blood mononuclear cells (PBMCs). Moreover, we validated the activation and promotion efficacy of U4CpG in patient-derived blood cells, and HIV-1 spread was significantly suppressed by a low dosage of the immunostimulant. Furthermore, U4CpG-treated PBMC cultured medium elicited transcription of latent HIV-1 in U1 cells indicating that U4CpG reversed HIV-1 latency. Thus, the functions of U4CpG in eradicating HIV-1 by enhancing immunity and reversing latency make the material a potential candidate for clinical studies dealing with viral infection.

Modulation of cell membrane functionalization with aggregates of oligodeoxynucleotides containing alkyl chain-modified uridines

In this study, we prepared oligodeoxynucleotides (ODNs) containing the uridine base modified by an alkyl chain at the 5-position (AU) and characterized their aggregate formation, localization, and functions in cells. These experiments revealed that aggregates of these ODNs were readily transported into cells, but their localization was dependent upon the number of hydrophobic units. ODNs with one modified AU were transported in the cytosol, while ODNs with multiple AU modifications resulted in their accumulation at the cell membrane. We also examined the ability of the AU-modified ODNs to capture small molecules at the cell membrane and their cellular uptake. We positioned a thioflavin-T (ThT)-binding aptamer on the cell membrane by means of hybridization with ODNs with three AUs at the strand end. Treatment with ThT resulted in its efficient uptake into cells, due to the capture of the ThT by the aptamers on the cell membrane. Thus, we demonstrated the functionalization of cell membranes with modified ODNs and the efficient delivery of small molecules into the cells.

Controlled Aggregation of a Perylene-Derived Probe for Near-Infrared Fluorescence Imaging and Phototherapy

The design and synthesis of water-soluble phototherapeutic agents with near-infrared (NIR) fluorescence emission is highly desirable for cancer diagnosis and treatment. Here, we report the construction of an amphiphilic perylene-derived photosensitizer, AP. AP shows NIR emission with large Stokes shift (130 nm) and high 1O2 quantum yield (22%). It can self-assemble into nanoparticles in aqueous solution with quenched fluorescence emission due to aggregation-induced quenching. Upon membrane anchoring, AP is able to disassemble into free monomer molecules and specifically "light up" the cell membrane without the usually required washing procedures. Furthermore, AP is subsequently used for the efficient photodynamic therapy against cancer cells and solid tumors. The in vitro and in vivo experiments clearly indicate that AP is suitable for biological imaging and can serve as a promising photosensitizer for tumor suppression.

Recent Progress of DNA Nanostructures on Amphiphilic Membranes

Employing DNA nanostructures mimicking membrane proteins on artificial amphiphilic membranes have been widely developed to understand the structures and functions of the natural membrane systems. In this review, the recent developments in artificial systems constructed by amphiphilic membranes and DNA nanostructures are summarized. First, the preparations and properties of the amphipathic bilayer models are introduced. Second, the interactions are discussed between the membrane and the DNA nanostructures, as well as their coassembly behaviors. Next, the alternative systems related to membrane protein-mediated signal transmission, selective distribution, transmembrane channels, and membrane fusion are also introduced. Moreover, the constructions of membrane skeleton protein-mimicking DNA nanostructures are also highlighted.

Functionalization of Cellular Membranes with DNA Nanotechnology

Due to its versatility and programmability, DNA nanotechnology has greatly expanded the experimental toolbox for biomedical research. Recent advances allow reliable and efficient functionalization of cellular plasma membranes with a variety of synthetic DNA constructs, ranging from single strands to complex 3D DNA origami. The scope for applications, which probe biophysical parameters or equip cells with novel functions, is rapidly increasing. These applications extend from programmed cellular connectivity and tissue engineering to molecular force measurements, controlled receptor-ligand interactions, membrane-anchored biosensors, and artificial transmembrane structures. Here, we give guidance on different strategies to functionalize cellular membranes with DNA nanotechnology and summarize current trends employing membrane-anchored DNA as a tool in biophysics, cell biology, and synthetic biology.

Recent Advances of DNA Nanostructure-Based Cell Membrane Engineering

Materials that can regulate the composition and structure of the cell membrane to fabricate engineered cells with defined functions are in high demand. Compared with other biomolecules, DNA has unique advantages in cell membrane engineering due to its excellent programmability and biocompatibility. Especially, the near-atomic scale precision of DNA nanostructures facilitates the investigation of structure-property relations on the cell membrane. In this review, first the state of the art of functional DNA nanostructures is summarized, and then the overview of the use of DNA nanostructures to engineer the cell membrane is presented. Subsequently, applications of DNA nanostructures in modifying cell membrane morphology, controlling ions transport, and synthesizing high precise liposomes are highlighted. Finally, the challenges and outlook on using DNA nanostructures for cell membrane engineering are discussed.

Combination of DNA with polymers

The preparation and applications of DNA containing polymers are comprehensively reviewed, and they are in the form of DNA−polymer covalent conjugators, supramolecular assemblies and hydrogels for advanced materials with promising features.

Bioapplications of DNA nanotechnology at the solid-liquid interface

DNA nanotechnology engineered at the solid-liquid interface has advanced our fundamental understanding of DNA hybridization kinetics and facilitated the design of improved biosensing, bioimaging and therapeutic platforms. Three research branches of DNA nanotechnology exist: (i) structural DNA nanotechnology for the construction of various nanoscale patterns; (ii) dynamic DNA nanotechnology for the operation of nanodevices; and (iii) functional DNA nanotechnology for the exploration of new DNA functions. Although the initial stages of DNA nanotechnology research began in aqueous solution, current research efforts have shifted to solid-liquid interfaces. Based on shape and component features, these interfaces can be classified as flat interfaces, nanoparticle interfaces, and soft interfaces of DNA origami and cell membranes. This review briefly discusses the development of DNA nanotechnology. We then highlight the important roles of structural DNA nanotechnology in tailoring the properties of flat interfaces and modifications of nanoparticle interfaces, and extensively review their successful bioapplications. In addition, engineering advances in DNA nanodevices at interfaces for improved biosensing both in vitro and in vivo are presented. The use of DNA nanotechnology as a tool to engineer cell membranes to reveal protein levels and cell behavior is also discussed. Finally, we present challenges and an outlook for this emerging field.

Nanomaterials meet zebrafish: Toxicity evaluation and drug delivery applications

With the rapid development of engineered nanomaterials for various applications, in vivo toxicological studies for evaluating the potential hazardous effects of nanomaterials on environmental and human safety are in urgent need. Zebrafish has long been considered as the "gold standard" for biosafety assessments of chemicals and pollutants due to its high fecundity, cost-effectiveness, well-characterized developmental stages, optical transparency, and so forth. Thus, zebrafish holds great potential for high-throughput nanotoxicity screening. In this review, we summarize the in vivo toxicological profiles of different nanomaterials, including Ag nanoparticles (NPs), CuO NPs, silica NPs, polymeric NPs, quantum dots, nanoscale metal-organic frameworks, etc, in zebrafish and focus on how the physicochemical properties (e.g., size, surface charge, and surface chemistry) of these nanomaterials influence their biosafety. In addition, we also report the recent advances of the in vivo delivery of nanopharmaceuticals using zebrafish as the model organism for therapeutic assessment, biodistribution tracking, and the controlled release of loaded drugs. Limitations and special considerations of zebrafish model are also discussed. Overall, zebrafish is expected to serve as a high-throughput screening platform for nanotoxicity and drug delivery assessment, which may instruct the design of safe nanomaterials and more effective nanomedicines.

Preparation of Well-Defined Polymers and DNA-Polymer Bioconjugates via Small-Volume eATRP in the Presence of Air

An aqueous electrochemically mediated atom transfer radical polymerization (eATRP) was performed in a small volume solution (75 μL) deposited on a screen-printed electrode (SPE). The reaction was open to air, thanks to the use of glucose oxidase (GOx) as an oxygen scavenger. Well-defined poly(2-(methylsulfinyl)ethyl acrylate) (PMSEA), poly(oligo(ethylene oxide) methyl ether methacrylate) (POEOMA), and corresponding DNA-polymer biohybrids were synthesized by the small-volume eATRP at room temperature. The reactions were simplified and polymerization rates increased by the application of the enzyme deoxygenating system and the compact electrochemical setup. Importantly, the volume of polymerization mixture was lowered to microliters, which not only decreases the cost for each reaction, but can also be potentially implemented in combinatorial chemistry and electrode-array configurations for high-throughput systems.

DNA Nanotechnology Enters Cell Membranes

DNA is more than a carrier of genetic information: It is a highly versatile structural motif for the assembly of nanostructures, giving rise to a wide range of functionalities. In this regard, the structure programmability is the main advantage of DNA over peptides, proteins, and small molecules. DNA amphiphiles, in which DNA is covalently bound to synthetic hydrophobic moieties, allow interactions of DNA nanostructures with artificial lipid bilayers and cell membranes. These structures have seen rapid growth with great potential for medical applications. In this Review, the current state of the art of the synthesis of DNA amphiphiles and their assembly into nanostructures are first summarized. Next, an overview on the interaction of these DNA amphiphiles with membranes is provided, detailing on the driving forces and the stability of the interaction. Moreover, the interaction with cell surfaces in respect to therapeutics, biological sensing, and cell membrane engineering is highlighted. Finally, the challenges and an outlook on this promising class of DNA hybrid materials are discussed.