Autonomous DNA nanostructures instructed by hierarchically concatenated chemical reaction networks

Engineering Modular DNA Reaction Networks for Signal Processing

Diversified molecular information-processing methods have significant implications for nanoscale manipulation and control, monitoring and disease diagnosis of organisms, and direct intervention in biological activities. However, as an effective approach for implementing multifunctional molecular information processing, DNA reaction networks (DRNs) with numerous functionally specialized molecular structures have challenged them on scale design, leading to increased network complexity, further causing problems such as signal leakage, attenuation, and cross-talk in network reactions. Our study developed a strategy for performing various signal-processing tasks through engineering modular DRNs. This strategy is based on a universal core unit with signal selection capability, and a time-adjustable signal self-resetting module is achieved by combing the core unit and self-resetting unit, which improves the time controllability of modular DRNs. In addition, multi-input and -output signal cross-catalytic and continuously adjustable signal delay modules were realized by combining core and threshold units, providing a flexible, precise method for modular DRNs to process the signal. The strategy simplifies the design of DRNs, helps generate design ideas for large-scale integrated DRNs with multiple functions, and provides prospects in biocomputing, gene regulation, and biosensing.

Recent advances in living cell nucleic acid probes based on nanomaterials for early cancer diagnosis

The early diagnosis of cancer is vital for effective treatment and improved prognosis. Tumor biomarkers, which can be used for the early diagnosis, treatment, and prognostic evaluation of cancer, have emerged as a topic of intense research interest in recent years. Nucleic acid, as a type of tumor biomarker, contains vital genetic information, which is of great significance for the occurrence and development of cancer. Currently, living cell nucleic acid probes, which enable the in situ imaging and dynamic monitoring of nucleic acids, have become a rapidly developing field. This review focuses on living cell nucleic acid probes that can be used for the early diagnosis of tumors. We describe the fundamental design of the probe in terms of three units and focus on the roles of different nanomaterials in probe delivery.

Scaling up of a Self-Confined Catalytic Hybridization Circuit for Robust microRNA Imaging

The precise regulation of cellular behaviors within a confined, crowded intracellular environment is highly amenable in diagnostics and therapeutics. While synthetic circuitry system through a concatenated chemical reaction network has rarely been reported to mimic dynamic self-assembly system. Herein, a catalytic self-defined circuit (CSC) for the hierarchically concatenated assembly of DNA domino nanostructures is engineered. By incorporating pre-sealed symmetrical fragments into the preying hairpin reactants, the CSC system allows the hierarchical DNA self-assembly via a microRNA (miRNA)-powered self-sorting catalytic hybridization reaction. With minimal strand complexity, this self-sustainable CSC system streamlined the circuit component and achieved localization-intensified cascaded signal amplification. Profiting from the self-adaptively concatenated hybridization reaction, a reliable and robust method has been achieved for discriminating carcinoma tissues from the corresponding para-carcinoma tissues. The CSC-sustained self-assembly strategy provides a comprehensive and smart toolbox for organizing various hierarchical DNA nanostructures, which may facilitate more insights for clinical diagnosis and therapeutic assessment.

DNA-empowered synthetic cells as minimalistic life forms

Cells, the fundamental units of life, orchestrate intricate functions - motility, adaptation, replication, communication, and self-organization within tissues. Originating from spatiotemporally organized structures and machinery, coupled with information processing in signalling networks, cells embody the 'sensor-processor-actuator' paradigm. Can we glean insights from these processes to construct primitive artificial systems with life-like properties? Using de novo design approaches, what can we uncover about the evolutionary path of life? This Review discusses the strides made in crafting synthetic cells, utilizing the powerful toolbox of structural and dynamic DNA nanoscience. We describe how DNA can serve as a versatile tool for engineering entire synthetic cells or subcellular entities, and how DNA enables complex behaviour, including motility and information processing for adaptive and interactive processes. We chart future directions for DNA-empowered synthetic cells, envisioning interactive systems wherein synthetic cells communicate within communities and with living cells.

Phototriggered Equilibrated and Transient Orthogonally Operating Constitutional Dynamic Networks Guiding Biocatalytic Cascades

The photochemical deprotection of structurally engineered o-nitrobenzylphosphate-caged hairpin nucleic acids is introduced as a versatile method to evolve constitutional dynamic networks, CDNs. The photogenerated CDNs, in the presence of fuel strands, interact with auxiliary CDNs, resulting in their dynamically equilibrated reconfiguration. By modification of the constituents associated with the auxiliary CDNs with glucose oxidase (GOx)/horseradish peroxidase (HRP) or the lactate dehydrogenase (LDH)/nicotinamide adenine dinucleotide (NAD+) cofactor, the photogenerated CDN drives the orthogonal operation upregulated/downregulated operation of the GOx/HRP and LDH/NAD+ biocatalytic cascade in the conjugate mixture of auxiliary CDNs. Also, the photogenerated CDN was applied to control the reconfiguration of coupled CDNs, leading to upregulated/downregulated formation of the antithrombin aptamer units, resulting in the dictated inhibition of thrombin activity (fibrinogen coagulation). Moreover, a reaction module consisting of GOx/HRP-modified o-nitrobenzyl phosphate-caged DNA hairpins, photoresponsive caged auxiliary duplexes, and nickase leads upon irradiation to the emergence of a transient, dissipative CDN activating in the presence of two alternate auxiliary triggers, achieving transient operation of up- and downregulated GOx/HRP biocatalytic cascades.

DNA as a universal chemical substrate for computing and data storage

DNA computing and DNA data storage are emerging fields that are unlocking new possibilities in information technology and diagnostics. These approaches use DNA molecules as a computing substrate or a storage medium, offering nanoscale compactness and operation in unconventional media (including aqueous solutions, water-in-oil microemulsions and self-assembled membranized compartments) for applications beyond traditional silicon-based computing systems. To build a functional DNA computer that can process and store molecular information necessitates the continued development of strategies for computing and data storage, as well as bridging the gap between these fields. In this Review, we explore how DNA can be leveraged in the context of DNA computing with a focus on neural networks and compartmentalized DNA circuits. We also discuss emerging approaches to the storage of data in DNA and associated topics such as the writing, reading, retrieval and post-synthesis editing of DNA-encoded data. Finally, we provide insights into how DNA computing can be integrated with DNA data storage and explore the use of DNA for near-memory computing for future information technology and health analysis applications.

Transient co-assemblies of micron-scale colloids regulated by ATP-fueled reaction networks

Self-assembly of colloidal particles offers an attractive bottom-up approach to functional materials. Current design strategies for colloidal assemblies are mostly based on thermodynamically controlled principles and lack autonomous behavior. The next advance in the properties of colloidal assemblies will come from coupling these structures to out-of-equilibrium chemical reaction networks furnishing them with autonomous and dynamic behavior. This, however, constitutes a major challenge of carefully modulating the interparticle potentials on a temporal circuit program and avoiding kinetic trapping and irreversible aggregation. Herein, we report the coupling of a fuel-driven DNA-based enzymatic reaction network (ERN) to micron-sized colloidal particles to achieve their transient co-assembly. The ERN operating on the molecular level transiently releases an Output strand which links two DNA functionalized microgel particles together into co-assemblies with a programmable assembly lifetime. The system generates minimal waste and recovers all components of the ERN after the consumption of the ATP fuel. The system can be reactivated by addition of new fuel as shown for up to three cycles. The design can be applied to organize other building blocks into hierarchical structures and materials with advanced biomimetic properties.

A Spatially Programmable DNA Nanorobot Arm to Modulate Anisotropic Gold Nanoparticle Assembly by Enzymatic Excision

Programmable assembly of gold nanoparticle superstructures with precise spatial arrangement has drawn much attention for their unique characteristics in plasmonics and biomedicine. Bio-inspired methods have already provided programmable, molecular approaches to direct AuNP assemblies using biopolymers. The existing methods, however, predominantly use DNA as scaffolds to directly guide the AuNP interactions to produce intended superstructures. New paradigms for regulating AuNP assembly will greatly enrich the toolbox for DNA-directed AuNP manipulation and fabrication. Here, we developed a strategy of using a spatially programmable enzymatic nanorobot arm to modulate anisotropic DNA surface modifications and assembly of AuNPs. Through spatial controls of the proximity of the reactants, the locations of the modifications were precisely regulated. We demonstrated the control of the modifications on a single 15 nm AuNP, as well as on a rectangular DNA origami platform, to direct unique anisotropic AuNP assemblies. This method adds an alternative enzymatic manipulation to DNA-directed AuNP superstructure assembly.

Mean-field models for the chemical fueling of transient soft matter states

The chemical fueling of transient states (CFTS) is a powerful process to control the nonequilibrium structuring and the homeostatic function of adaptive soft matter systems. Here, we introduce a simple mean-field model of CFTS based on the activation of metastable equilibrium states in a tilted 'Landau' bistable energy landscape along a coarse-grained reaction coordinate (or 'order parameter') triggered by a nonmonotonic two-step chemical fueling reaction. Evaluation of the model in the quasi-static (QS) limit-valid for fast system relaxation-allows us to extract useful analytical laws for the critical activation concentration and duration of the transient states in dependence of physical parameters, such as rate constants, fuel concentrations, and the system's distance to its equilibrium transition point. We apply our model in the QS limit explicitly to recent experiments of CFTS of collapsing responsive microgels and find a very good performance with only a few global and physically interpretable fitting parameters, which can be employed for programmable material design. Moreover, our model framework also allows a thermodynamic analysis of the energy and performed work in the system. Finally, we go beyond the QS limit, where the system's response is slow and retarded versus the chemical reaction, using an overdamped Smoluchowski approach. The latter demonstrates how internal system time scales can be used to tune the time-dependent behavior and programmed delay of the transient states in full nonequilibrium.

Engineering DNA-based cytoskeletons for synthetic cells

The development and bottom-up assembly of synthetic cells with a functional cytoskeleton sets a major milestone to understand cell mechanics and to develop man-made machines on the nano- and microscale. However, natural cytoskeletal components can be difficult to purify, deliberately engineer and reconstitute within synthetic cells which therefore limits the realization of multifaceted functions of modern cytoskeletons in synthetic cells. Here, we review recent progress in the development of synthetic cytoskeletons made from deoxyribonucleic acid (DNA) as a complementary strategy. In particular, we explore the capabilities and limitations of DNA cytoskeletons to mimic functions of natural cystoskeletons like reversible assembly, cargo transport, force generation, mechanical support and guided polymerization. With recent examples, we showcase the power of rationally designed DNA cytoskeletons for bottom-up assembled synthetic cells as fully engineerable entities. Nevertheless, the realization of dynamic instability, self-replication and genetic encoding as well as contractile force generating motors remains a fruitful challenge for the complete integration of multifunctional DNA-based cytoskeletons into synthetic cells.

Transient Dynamic Operation of G-Quadruplex-Gated Glucose Oxidase-Loaded ZIF-90 Metal-Organic Framework Nanoparticle Bioreactors

Glucose oxidase-loaded ZIF-90 metal-organic framework nanoparticles conjugated to hemin-G-quadruplexes act as functional bioreactor hybrids operating transient dissipative biocatalytic cascaded transformations consisting of the glucose-driven H2O2-mediated oxidation of Amplex-Red to resorufin or the glucose-driven generation of chemiluminescence by the H2O2-mediated oxidation of luminol. One system involves the fueled activation of a reaction module leading to the temporal formation and depletion of the bioreactor conjugate operating the nickase-guided transient biocatalytic cascades. The second system demonstrates the fueled activation of a reaction module yielding a bioreactor conjugate operating the exonuclease III-dictated transient operation of the two biocatalytic cascades. The temporal operations of the bioreactor circuits are accompanied by kinetic models and computational simulations enabling us to predict the dynamic behavior of the systems subjected to different auxiliary conditions.

Timed Pulses in DNA Strand Displacement Reactions

Inspired by naturally occurring regulatory mechanisms that allow complex temporal pulse features with programmable delays, we demonstrate here a strategy to achieve temporally programmed pulse output signals in DNA-based strand displacement reactions (SDRs). To achieve this, we rationally designed input strands that, once bound to their target duplex, can be gradually degraded, resulting in a pulse output signal. We also designed blocker strands that suppress strand displacement and determine the time at which the pulse reaction is generated. We show that by controlling the degradation rate of blocker and input strands, we can finely control the delayed pulse output over a range of 10 h. We also prove that it is possible to orthogonally delay two different pulse reactions in the same solution by taking advantage of the specificity of the degradation reactions for the input and blocker strands. Finally, we show here two possible applications of such delayed pulse SDRs: the time-programmed pulse decoration of DNA nanostructures and the sequentially appearing and self-erasing formation of DNA-based patterns.

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.

DNA-Based Signaling Networks for Transient Colloidal Co-Assemblies

Programmable chemical circuits inspired by signaling networks in living cells are a promising approach for the development of adaptive and autonomous self-assembling molecular systems and material functions. Progress has been made at the molecular level, but connecting molecular control circuits to self-assembling larger elements such as colloids that enable real-space studies and access to functional materials is sparse and can suffer from kinetic traps, flocculation, or difficult system integration protocols. Herein, we report a toehold-mediated DNA strand displacement reaction network capable of autonomously directing two different microgels into transient and self-regulating co-assemblies. The microgels are functionalized with DNA and become elemental components of the network. The flexibility of the circuit design allows the installation of delay phases or accelerators by chaining additional circuit modules upstream or downstream of the core circuit. The design provides an adaptable and robust route to regulate other building blocks for advanced biomimetic functions.

Mechanosensitive non-equilibrium supramolecular polymerization in closed chemical systems

Chemical fuel-driven supramolecular systems have been developed showing out-of-equilibrium functions such as transient gelation and oscillations. However, these systems suffer from undesired waste accumulation and they function only in open systems. Herein, we report non-equilibrium supramolecular polymerizations in a closed system, which is built by viologens and pyranine in the presence of hydrazine hydrate. On shaking, the viologens are quickly oxidated by air followed by self-assembly of pyranine into micrometer-sized nanotubes. The self-assembled nanotubes disassemble spontaneously over time by the reduced agent, with nitrogen as the only waste product. Our mechanosensitive dissipative system can be extended to fabricate a chiral transient supramolecular helix by introducing chiral-charged small molecules. Moreover, we show that shaking induces transient fluorescence enhancement or quenching depending on substitution of viologens. Ultrasound is introduced as a specific shaking way to generate template-free reproducible patterns. Additionally, the shake-driven transient polymerization of amphiphilic naphthalenetetracarboxylic diimide serves as further evidence of the versatility of our mechanosensitive non-equilibrium system.

Dynamic Transcription Machineries Guide the Synthesis of Temporally Operating DNAzymes, Gated and Cascaded DNAzyme Catalysis

Transient transcription machineries play important roles in the dynamic modulation of gene expression and the sequestered regulation of cellular networks. The present study emulates such processes by designing artificial reaction modules consisting of transcription machineries that guide the transient synthesis of catalytic DNAzymes, the transient operation of gated DNAzymes, and the temporal activation of an intercommunicated DNAzyme cascade. The reaction modules rely on functional constituents that lead to the triggered activation of transcription machineries in the presence of the nucleoside triphosphates oligonucleotide fuel, yielding the transient formation and dissipative depletion of the intermediate DNAzyme(s) products. The kinetics of the transient DNAzyme networks are computationally simulated, allowing to predict and experimentally validate the performance of the systems under different auxiliary conditions. The study advances the field of systems chemistry by introducing transcription machinery-based networks for the dynamic control over transient catalysis─a primary step toward life-like cellular assemblies.

Programming Non-Nucleic Acid Molecules into Computational Nucleic Acid Systems

Nucleic acid (NA) computation has been widely developed in the past years to solve kinds of logic and mathematic issues in both information technologies and biomedical analysis. However, the difficulty to integrate non-NA molecules limits its power as a universal platform for molecular computation. Here, we report a versatile prototype of hybridized computation integrated with both nucleic acids and non-NA molecules. Employing the conformationally controlled ligand converters, we demonstrate that non-NA molecules, including both small molecules and proteins, can be computed as nucleic acid strands to construct the circuitry with increased complexity and scalability, and can be even programmed to solve arithmetical calculations within the computational nucleic acid system. This study opens a new door for molecular computation in which all-NA circuits can be expanded with integration of various ligands, and meanwhile, ligands can be precisely programmed by the nuclei acid computation.

Communication and Cross-Regulation between Chemically Fueled Sender and Receiver Reaction Networks

Nature connects multiple fuel-driven chemical/enzymatic reaction networks (CRNs/ERNs) via cross-regulation to hierarchically control biofunctions for a tailored adaption in complex sensory landscapes. Herein, we introduce a facile example of communication and cross-regulation among two fuel-driven DNA-based ERNs regulated by a concatenated RNA transcription regulator. ERN1 ("sender") is designed for the fuel-driven promoter formation for T7 RNA polymerase, which activates RNA transcription. The produced RNA can deactivate or activate DNA in ERN2 ("receiver") by toehold-mediated strand displacement, leading to a communication between two ERNs. The RNA from ERN1 can repress or promote the fuel-driven state of ERN2; ERN2 in turn feedbacks to regulate the lifetime of ERN1. Furthermore, the incorporation of RNase H allows for RNA degradation and enables the autonomous recovery of ERN2. We believe that concatenation of multiple CRNs/ERNs provides a basis for the design of more elaborate autonomous regulatory mechanisms in systems chemistry and synthetic biology.

Regulating DNA-Hybridization Using a Chemically Fueled Reaction Cycle

Molecular machines, such as ATPases or motor proteins, couple the catalysis of a chemical reaction, most commonly hydrolysis of nucleotide triphosphates, to their conformational change. In essence, they continuously convert a chemical fuel to drive their motion. An outstanding goal of nanotechnology remains to synthesize a nanomachine with similar functions, precision, and speed. The field of DNA nanotechnology has given rise to the engineering precision required for such a device. Simultaneously, the field of systems chemistry developed fast chemical reaction cycles that convert fuel to change the function of molecules. In this work, we thus combined a chemical reaction cycle with the precision of DNA nanotechnology to yield kinetic control over the conformational state of a DNA hairpin. Future work on such systems will result in out-of-equilibrium DNA nanodevices with precise functions.

Design, Mechanical Properties, and Dynamics of Synthetic DNA Filaments

Over the past 40 years, structural and dynamic DNA nanotechnologies have undoubtedly demonstrated to be effective means for organizing matter at the nanoscale and reconfiguring equilibrium structures, in a predictable fashion and with an accuracy of a few nanometers. Recently, novel concepts and methodologies have been developed to integrate nonequilibrium dynamics into DNA nanostructures, opening the way to the construction of synthetic materials that can adapt to environmental changes and thus acquire new properties. In this Review, we summarize the strategies currently applied for the construction of synthetic DNA filaments and conclude by reporting some recent and most relevant examples of DNA filaments that can emulate typical structural and dynamic features of the cytoskeleton, such as compartmentalization in cell-like vesicles, support for active transport of cargos, sustained or transient growth, and responsiveness to external stimuli.

Programming Dissipation Systems by DNA Timer for Temporally Regulating Enzyme Catalysis and Nanostructure Assembly

Live cells precisely control their temporal pattern in energy dissipative processes such as catalysis and assembly. Here, we demonstrate a DNA-based artificial dissipative nonequilibrium system where the transient state is controlled by the processive digestion of λ-exonuclease (λ Exo). This enzyme reaction serves as an orthogonal and independent molecular timer allowing for the programmable regulation of the transient-state lifetime. This dissipation system is concatenated to enzyme catalysis and nanostructure assembly networks. Dynamic activation of enzyme catalysis and dynamic disassembly of DNA nanotubes (DNT) are realized, and the state lifetimes of these systems are accurately encoded by the DNA timer. This work demonstrates nontrivial dissipation systems with built-in molecular timers, which can be a useful tool for developing artificial reaction networks and nanostructures with enhanced complexities and intelligence.

Dissipative DNA nanotechnology

DNA nanotechnology has emerged as a powerful tool to precisely design and control molecular circuits, machines and nanostructures. A major goal in this field is to build devices with life-like properties, such as directional motion, transport, communication and adaptation. Here we provide an overview of the nascent field of dissipative DNA nanotechnology, which aims at developing life-like systems by combining programmable nucleic-acid reactions with energy-dissipating processes. We first delineate the notions, terminology and characteristic features of dissipative DNA-based systems and then we survey DNA-based circuits, devices and materials whose functions are controlled by chemical fuels. We emphasize how energy consumption enables these systems to perform work and cyclical tasks, in contrast with DNA devices that operate without dissipative processes. The ability to take advantage of chemical fuel molecules brings dissipative DNA systems closer to the active molecular devices that exist in nature.

1D Colloidal chains: recent progress from formation to emergent properties and applications

Integrating nanoscale building blocks of low dimensionality (0D; i.e., spheres) into higher dimensional structures endows them and their corresponding materials with emergent properties non-existent or only weakly existent in the individual building blocks. Constructing 1D chains, 2D arrays and 3D superlattices using nanoparticles and colloids therefore continues to be one of the grand goals in colloid and nanomaterial science. Amongst these higher order structures, 1D colloidal chains are of particular interest, as they possess unique anisotropic properties. In recent years, the most relevant advances in 1D colloidal chain research have been made in novel synthetic methodologies and applications. In this review, we first address a comprehensive description of the research progress concerning various synthetic strategies developed to construct 1D colloidal chains. Following this, we highlight the amplified and emergent properties of the resulting materials, originating from the assembly of the individual building blocks and their collective behavior, and discuss relevant applications in advanced materials. In the discussion of synthetic strategies, properties, and applications, particular attention will be paid to overarching concepts, fresh trends, and potential areas of future research. We believe that this comprehensive review will be a driver to guide the interdisciplinary field of 1D colloidal chains, where nanomaterial synthesis, self-assembly, physical property studies, and material applications meet, to a higher level, and open up new research opportunities at the interface of classical disciplines.

Self-Regulating Colloidal Co-Assemblies That Accelerate Their Own Destruction via Chemo-Structural Feedback

Biological self‐assemblies self‐ and cross‐regulate each other via chemical reaction networks (CRNs) and feedback. Although artificial transient self‐assemblies have been realized via activation/deactivation CRNs, the transient structures themselves do mostly not engage in the CRN. We introduce a rational design approach for chemo‐structural feedback, and present a transient colloidal co‐assembly system, where the formed co‐assemblies accelerate their destruction autonomously. We achieve this by immobilizing enzymes of a deactivating acid‐producing enzymatic cascade on pH‐switchable microgels that can form co‐assemblies at high pH. Since the enzyme partners are immobilized on individual microgels, the co‐assembled state brings them close enough for enhanced acid generation. The amplified deactivator production (acid) leads to an almost two‐fold reduction in the lifetime of the transiently formed pH‐state. Our study thus introduces versatile mechanisms for chemo‐structural feedback.

Dissipative Organization of DNA Oligomers for Transient Catalytic Function

The development of synthetic non-equilibrium systems opens doors for man-made life-like materials. Yet, creating distinct transient functions from artificial fuel-driven structures remains a challenge. Building on our ATP-driven dynamic covalent DNA assembly in an enzymatic reaction network of concurrent ATP-powered ligation and restriction, we introduce ATP-fueled transient organization of functional subunits for various functions. The programmability of the ligation/restriction site allows to precisely organize multiple sticky-end-encoded oligo segments into double-stranded (ds) DNA complexes. We demonstrate principles of ATP-driven organization into sequence-defined oligomers by sensing barcode-embedded targets with different defects. Furthermore, ATP-fueled DNAzymes for substrate cleavage are achieved by transiently ligating two DNAzyme subunits into a dsDNA complex, rendering ATP-fueled transient catalytic function.

Multifunctional Hyphae Carbon Powering Lithium-Sulfur Batteries

Biotechnology can bring new breakthroughs on design and fabrication of energy materials and devices. In this work, a novel and facile biological self-assembly technology to fabricate multifunctional Rhizopus hyphae carbon fiber (RHCF) and its derivatives on a large scale for electrochemical energy storage is proposed. Crosslinked hollow carbon fibers are successfully prepared by conversion of Rhizopus hyphae, and macroscopic production of centimeter-level carbon balls consisting of hollow RHCFs is further realized. Moreover, the self-assembled RHCF balls show strong adsorption characteristics on metal ions and can be converted into a series of derivatives such as RHCF/metal oxides. Notably, the designed RHCF derivatives are demonstrated with powerful multifunctionability as cathode, anode, and separator for lithium-sulfur batteries (LSBs). The RHCF can act as the host material to combine with metal oxide (CoO) and S, Li metal, and a polypropylene (PP) separator to form a new RHCF/CoO-S cathode, an RHCF/Li anode, and an RHCF/PP separator, respectively. Consequently, the optimized LSB full cell presents excellent cycling performance and superior high-rate capacity (881.3 mA h g^-1 at 1 C). This work provides a new method for large-scale preparation of hollow carbon fibers and derivatives for advanced energy storage and conversion.

pH-responsive aggregate consisted of oligodeoxynucleotides bearing nitrophenol group that deliver drugs into acidic cells

A decrease in pH is observed in most solid tumors, thus, the development of drug delivery systems that respond to slightly acidic extracellular pH environment is important in providing tumor-targeted therapies. DNA aggregates can act as useful drug delivery agents, and therefore, we designed an artificial oligodeoxynucleotides (ODNs) that form an aggregate only under acidic conditions in this study. In other words, we expected that if we could make DNA aggregates that form only in an acidic environment and that encapsulate drugs, it would be possible to transport drugs to tumor tissues selectively. Nitrophenol derivatives, which undergo protonation and deprotonation in response to pH changes, was introduced into ODNs. The ODNs formed aggregates under weakly acidic conditions because of expression of amphiphilicity, which was induced by protonation of nitrophenol unit, and were smoothly taken up into cells. We also found that the aggregates transport anticancer drug, 5FU, into acidified cells to show cytotoxic effects.

Spontaneous Reorganization of DNA-Based Polymers in Higher Ordered Structures Fueled by RNA

We demonstrate a strategy that allows for the spontaneous reconfiguration of self-assembled DNA polymers exploiting RNA as chemical fuel. To do this, we have rationally designed orthogonally addressable DNA building blocks that can be transiently deactivated by RNA fuels and subtracted temporarily from participation in the self-assembly process. Through a fine modulation of the rate at which the building blocks are reactivated we can carefully control the final composition of the polymer and convert a disordered polymer in a higher order polymer, which is disfavored from a thermodynamic point of view. We measure the dynamic reconfiguration via fluorescent signals and confocal microscopy, and we derive a kinetic model that captures the experimental results. Our approach suggests a novel route toward the development of biomolecular materials in which engineered chemical reactions support the autonomous spatial reorganization of multiple components.