T Lymphocyte-Captured DNA Network for Localized Immunotherapy

High-content tailoring strategy to improve the multifunctionality of functional nucleic acids

Functional nucleic acids (FNAs) have attracted increasing attention in recent years due to their diverse physiological functions. The understanding of their conformational recognition mechanisms has advanced through nucleic acid tailoring strategies and sequence optimization. With the development of the FNA tailoring techniques, they have become a methodological guide for nucleic acid repurposing. Therefore, it is necessary to systematize the relationship between FNA tailoring strategies and the development of nucleic acid multifunctionality. This review systematically categorizes eight types of FNA multifunctionality, and introduces the traditional FNA tailoring strategy from five aspects, including deletion, substitution, splitting, fusion and elongation. Based on the current state of FNA modification, a new generation of FNA tailoring strategy, called the high-content tailoring strategy, was unprecedentedly proposed to improve FNA multifunctionality. In addition, the multiple applications of rational tailoring-driven FNA performance enhancement in various fields were comprehensively summarized. The limitations and potential of FNA tailoring and repurposing in the future are also explored in this review. In summary, this review introduces a novel tailoring theory, systematically summarizes eight FNA performance enhancements, and provides a systematic overview of tailoring applications across all categories of FNAs. The high-content tailoring strategy is expected to expand the application scenarios of FNAs in biosensing, biomedicine and materials science, thus promoting the synergistic development of various fields.

Microfluidic-Assisted Self-Assembly of Molecular Hydrogelator at Water-Water Interfaces for Continuous Fabrication of Supramolecular Microcapsules

Control over the self-assembly of small molecules at specific areas is of great interest for many high-tech applications, yet remains a formidable challenge. Here, how the self-assembly of hydrazone-based molecular hydrogelators can be specifically triggered at water-water interfaces for the continuous fabrication of supramolecular microcapsules by virtue of the microfluidic technique is demonstrated. The non-assembling hydrazide- and aldehyde-based hydrogelator precursors are distributed in two immiscible aqueous polymer solutions, respectively, through spontaneous phase separation. In the presence of catalysts, hydrazone-based hydrogelators rapidly form and self-assemble into hydrogel networks at the generated water-water interfaces. Relying on the microfluidic technique, microcapsules bearing a shell of supramolecular hydrogel are continuously produced. The obtained microcapsules can effectively load enzymes, enabling localized enzymatic growth of supramolecular fibrous supramolecular structures, reminiscent of the self-assembly of biological filaments within living cells. This work may contribute to the development of biomimetic supramolecular carriers for applications in biomedicine and fundamental research, for instance, the construction of protocells.

Self-Assembled DNA Microflowers for Platelet-Derived Extracellular Vesicle Isolation and Infected Wound Healing

Platelet-derived extracellular vesicles (PEVs) showing great potential in wound healing have attracted increasing attention recently. Nondestructive isolation and effective utilization strategies are highly conducive for PEVs developing into recognized therapeutic entities. Here, we present an efficient strategy for PEV isolation and bacterial infected wound healing based on self-assembled DNA microflowers. First, DNA microflowers are prepared using rolling circle amplification. Then, the hydrophobic interaction between cholesteryl modified on DNA microflowers and the phospholipid bilayer membrane of PEVs leads to the formation of a network structure with improved mechanical strength and the separation of PEVs from biological samples. Finally, controlled release of PEVs is achieved through bacterial-induced hydrogel degradation. In vitro experiments demonstrate the obtained DNA hydrogel with good cytocompatibility and therapeutic potential. Taken together, the DNA microflower-based hydrogels with bioadhesive, self-healing, tunable mechanical properties and bacteria-responsive behavior offer substantial potential for EV isolation and wound healing.

Near-Infrared Light-Activatable DNA Tentacles for Efficient Inhibition of Tumor Metastasis by Bio-Orthogonal Cell Assembly

Tumor metastasis remains a major challenge in cancer management. Among various treatment strategies, immune cell-based cancer therapy holds a great potential for inhibiting metastasis. However, its wide application in cancer therapy is restricted by complex preparations, as well as inadequate homing and controllability. Herein, we present a groundbreaking approach for bioorthogonally manipulating tumor-NK (natural killer) cell assembly to inhibit tumor metastasis. Multiple dibenzocyclootyne (DBCO) groups decorated long single-stranded DNA were tail-modified on core-shell upconversion nanoparticles (CSUCNPs) and condensed by photosensitive chemical linker (PC-Linker) DNA to shield most of the DBCO groups. On the one hand, the light-triggered DNA scaffolds formed a cross-linked network by click chemistry, effectively impeding tumor cell migration. On the other hand, the efficient cellular assembly facilitated the effective communication between tumor cells and NK-92 cells, leading to enhanced immune response against tumors and further suppression of tumor metastasis. These features make our strategy highly applicable to a wide range of metastatic cancers.

A DNA/Poly-(L-lysine) Hydrogel with Long Shelf-Time for 3D Cell Culture

Deoxyribonucleic acid (DNA)-based hydrogels are emerging as promising functional materials for biomedical applications. However, the shelf-time of DNA hydrogels in biological media is severely shortened by nucleases, which limit the application of DNA hydrogels. Herein, a DNA hydrogel with long shelf-time is reported for 3D cell culture. Poly-(L-lysine) (PLL) is introduced as both a cross-linker and a protectant. The electrostatic interaction between PLL and DNA drove the formation of hydrogel. PLL coating on DNA increased the steric hindrance between DNA and nucleases, thus weakening the digestion of nucleases toward phosphodiester bond. As a result, the shelf-time of DNA/PLL hydrogel for 3D cell culture is extended from generally 1 day to longer than 15 days, which has not been achieved previously. Notably, poly-AS1411-aptamers are integrated to DNA/PLL hydrogels for anchoring U87 cells, and the cell encapsulation efficiency of the DNA/PLL hydrogels with aptamer is 4-time higher than that of the hydrogels without aptamer. DNA/PLL hydrogel provided a favorable microenvironment to support the proliferation of cells, which formed cell spheroid in 15 days. This protective coating strategy solves the long-standing problem on the shelf-time of DNA hydrogel, and is envisioned to promote the development of DNA hydrogel in more biomedical applications.

Engineered Bio-Based Hydrogels for Cancer Immunotherapy

Immunotherapy represents a revolutionary paradigm in cancer management, showcasing its potential to impede tumor metastasis and recurrence. Nonetheless, challenges including limited therapeutic efficacy and severe immune-related side effects are frequently encountered, especially in solid tumors. Hydrogels, a class of versatile materials featuring well-hydrated structures widely used in biomedicine, offer a promising platform for encapsulating and releasing small molecule drugs, biomacromolecules, and cells in a controlled manner. Immunomodulatory hydrogels present a unique capability for augmenting immune activation and mitigating systemic toxicity through encapsulation of multiple components and localized administration. Notably, hydrogels based on biopolymers have gained significant interest owing to their biocompatibility, environmental friendliness, and ease of production. This review delves into the recent advances in bio-based hydrogels in cancer immunotherapy and synergistic combinatorial approaches, highlighting their diverse applications. It is anticipated that this review will guide the rational design of hydrogels in the field of cancer immunotherapy, fostering clinical translation and ultimately benefiting patients.

Recent advances in functional nucleic acid decorated nanomaterials for cancer imaging and therapy

Nanomaterials possess unusual physicochemical properties including unique optical, magnetic, electronic properties, and large surface-to-volume ratio. However, nanomaterials face some challenges when they were applied in the field of biomedicine. For example, some nanomaterials suffer from the limitations such as poor selectivity and biocompatibility, low stability, and solubility. To address the above-mentioned obstacles, functional nucleic acid has been widely served as a powerful and versatile ligand for modifying nanomaterials because of their unique characteristics, such as ease of modification, excellent biocompatibility, high stability, predictable intermolecular interaction and recognition ability. The functionally integrating functional nucleic acid with nanomaterials has produced various kinds of nanocomposites and recent advances in applications of functional nucleic acid decorated nanomaterials for cancer imaging and therapy were summarized in this review. Further, we offer an insight into the future challenges and perspectives of functional nucleic acid decorated nanomaterials.

Directing the Encapsulation of Single Cells with DNA Framework Nucleator-Based Hydrogel Growth

Encapsulating individual mammalian cells with biomimetic materials holds potential in ex vivo cell culture and engineering. However, current methodologies often present tradeoffs between homogeneity, stability, and cell compatibility. Here, inspired by bacteria that use proteins stably anchored on their outer membranes to nucleate biofilm growth, we develop a single-cell encapsulation strategy by using a DNA framework structure as a nucleator (DFN) to initiate the growth of DNA hydrogels under cell-friendly conditions. We find that among the tested structures, the tetrahedral DFN can evenly and stably reside on cell membranes, effectively initiating hybridization chain reactions which generate homogeneously dense yet flexible single-cell encapsulation for diverse cell lines. The encapsulation persists for up to 72 hours in a serum-containing cell culture environment, representing a ~70-fold improvement compared to encapsulations mediated by single-stranded DNA nucleators. The metabolism and proliferation of the encapsulated cells are suppressed, but can be restored to the original efficiencies upon release, suggesting the superior cell compatibility of the encapsulation. We also find that compared to naked cells, the encapsulated cells exhibit a lower autophagy level after undergoing mechanical stress, suggesting the protective effect of the DNA encapsulation. This method may provide a new tool for ex vivo cell engineering.

A Smart DNA Hydrogel Enables Synergistic Immunotherapy and Photodynamic Therapy of Melanoma

Immunotherapy faces insufficient immune activation and limited immune effectiveness. Herein, we report a smart DNA hydrogel that enables the release of multivalent functional units at the tumor site to enhance the efficacy of immunotherapy. The smart DNA hydrogel was assembled from two types of ultra-long DNA chains synthesized via rolling circle amplification. One DNA chain contained immune adjuvant CpG oligonucleotides and polyaptamers for loading natural killer cell-derived exosomes; the other chain contained multivalent G-quadruplex for loading photodynamic agents. DNA chains formed DNA hydrogel through base-pairing. HhaI restriction endonuclease sites were designed between functional units. Upon stimuli in the tumor sites, the hydrogel was effectively cleaved by the released HhaI and disassembled into functional units. Natural killer cell-derived exosomes played an anti-tumor role, and the CpG oligonucleotide activated antigen-presenting cells to enhance the immunotherapy. Besides the tumor-killing effect of photodynamic therapy, the generated cellular debris acted as an immune antigen to further enhance the immunotherapeutic effect. In a mouse melanoma orthotopic model, the smart DNA hydrogel as a localized therapeutic agent, achieved a remarkable tumor suppression rate of 91.2 %. The smart DNA hydrogel exhibited enhanced efficacy of synergistic immunotherapy and photodynamic therapy, expanding the application of DNA materials in biomedicine.

Recent advances in the synthesis of single-stranded DNA in vitro

Single-stranded DNA (ssDNA) is the foundation of modern biology, with wide applications in gene editing, sequencing, DNA information storage, and materials science. However, synthesizing ssDNA with high efficiency, high throughput, and low error rate in vitro remains a major challenge. Various methods have been developed for ssDNA synthesis, and some significant results have been achieved. In this review, six main methods were introduced, including solid-phase oligonucleotide synthesis, terminal deoxynucleotidyl transferase-based ssDNA synthesis, reverse transcription, primer exchange reaction, asymmetric polymerase chain reaction, and rolling circle amplification. The advantages and limitations of each method were compared, as well as illustrate their representative achievements and applications. Especially, rolling circle amplification has received significant attention, including ssDNA synthesis, assembly, and application based on recent work. Finally, the future challenges and opportunities of ssDNA synthesis were summarized and discussed. Envisioning the development of new methods and significant progress will be made in the near future with the efforts of scientists around the world.

Rational Design of DNA Hydrogels Based on Molecular Dynamics of Polymers

In recent years, DNA has emerged as a fascinating building material to engineer hydrogel due to its excellent programmability, which has gained considerable attention in biomedical applications. Understanding the structure-property relationship and underlying molecular determinants of DNA hydrogel is essential to precisely tailor its macroscopic properties at molecular level. In this review, the rational design principles of DNA molecular networks based on molecular dynamics of polymers on the temporal scale, which can be engineered via the backbone rigidity and crosslinking kinetics, are highlighted. By elucidating the underlying molecular mechanisms and theories, it is aimed to provide a comprehensive overview of how the tunable DNA backbone rigidity and the crosslinking kinetics lead to desirable macroscopic properties of DNA hydrogels, including mechanical properties, diffusive permeability, swelling behaviors, and dynamic features. Furthermore, it is also discussed how the tunable macroscopic properties make DNA hydrogels promising candidates for biomedical applications, such as cell culture, tissue engineering, bio-sensing, and drug delivery.

Bimodal DNA self-origami material with nucleic acid function enhancement

BACKGROUND

The design of DNA materials with specific nanostructures for biomedical tissue engineering applications remains a challenge. High-dimensional DNA nanomaterials are difficult to prepare and are unstable; moreover, their synthesis relies on heavy metal ions. Herein, we developed a bimodal DNA self-origami material with good biocompatibility and differing functions using a simple synthesis method. We simulated and characterized this material using a combination of oxDNA, freeze-fracture electron microscopy, and atomic force microscopy. Subsequently, we optimized the synthesis procedure to fix the morphology of this material.

RESULTS

Using molecular dynamics simulation, we found that the bimodal DNA self-origami material exhibited properties of spontaneous stretching and curling and could be fixed in a single morphology via synthesis control. The application of different functional nucleic acids enabled the achievement of various biological functions, and the performance of functional nucleic acids was significantly enhanced in the material. Consequently, leveraging the various functional nucleic acids enhanced by this material will facilitate the attainment of diverse biological functions.

CONCLUSION

The developed design can comprehensively reveal the morphology and dynamics of DNA materials. We thus report a novel strategy for the construction of high-dimensional DNA materials and the application of functional nucleic acid-enhancing materials.

Functional Nucleic Acid-Based Immunomodulation for T Cell-Mediated Cancer Therapy

T cell-mediated immunity plays a pivotal role in cancer immunotherapy. The anticancer actions of T cells are coordinated by a sequence of biological processes, including the capture and presentation of antigens by antigen-presenting cells (APCs), the activation of T cells by APCs, and the subsequent killing of cancer cells by activated T cells. However, cancer cells have various means to evade immune responses. Meanwhile, these vulnerabilities provide potential targets for cancer treatments. Functional nucleic acids (FNAs) make up a class of synthetic nucleic acids with specific biological functions. With their diverse functionality, good biocompatibility, and high programmability, FNAs have attracted widespread interest in cancer immunotherapy. This Review focuses on recent research progress in employing FNAs as molecular tools for T cell-mediated cancer immunotherapy, including corresponding challenges and prospects.

A NIR Programmable In Vivo miRNA Magnifier for NIR-II Imaging of Early Stage Cancer

Aberrant expressions of biomolecules occur much earlier than tumor visualized size and morphology change, but their common measurement strategies such as biopsy suffer from invasive sampling process. In vivo imaging of slight biomolecule expression difference is urgently needed for early cancer detection. Fluorescence of rare earth nanoparticles (RENPs) in second near-infrared (NIR-II) region makes them appropriate tool for in vivo imaging. However, the incapacity to couple with signal amplification strategies, especially programmable signal amplification strategies, limited their application in lowly expressed biomarkers imaging. Here we develop a 980/808 nm NIR programmed in vivo microRNAs (miRNAs) magnifier by conjugating activatable DNAzyme walker set to RENPs, which achieves more effective NIR-II imaging of early stage tumor than size monitoring imaging technique. Dye FD1080 (FD1080) modified substrate DNA quenches NIR-II downconversion emission of RENPs under 808 nm excitation. The miRNA recognition region in DNAzyme walker is sealed by a photo-cleavable strand to avoid "false positive" signal in systemic circulation. Upconversion emission of RENPs under 980 nm irradiation activates DNAzyme walker for miRNA recognition and amplifies NIR-II fluorescence recovery of RENPs via DNAzyme catalytic reaction to achieve in vivo miRNA imaging. This strategy demonstrates good application potential in the field of early cancer detection.

Rational design of genotyping nanodevice for HPV subtype distinction

There are more than 200 subtypes of human papillomavirus (HPV), and high-risk HPVs are a leading cause of cervical cancer. Identifying the genotypes of HPV is significant for clinical diagnosis and cancer control. Herein, we used programmable and modified DNA as the backbone to construct fluorescent genotyping nanodevice for HPV subtype distinction. In our strategy, the dye-labeled single-stranded recognize-DNA (R-DNA) was hybridized with Black Hole Quencher (BHQ) labeled single-stranded link-DNA (L-DNA) to form three functionalized DNA (RL-DNA). Through the extension of polycytosine (poly-C) in L-DNA, three RL-DNAs can be more firmly adsorbed on graphene oxide to construct reliable genotyping nanodevice. The genotyping nanodevice had low background noise since the dual energy transfer, including Förster resonance energy transfer (FRET) from dye to BHQ and the resonance energy transfer (RET) from dye to graphene oxide. Meanwhile, the programmability of DNA allows the proposed strategy to simultaneously and selectively distinguish several HPV subtypes in solution using DNA labeled with different dyes. To demonstrate clinical potential, we show multiplexed assay of HPV subtypes in cervical scrapes, and it has been successfully applied in HPV-DNA analysis in cervical scrapes samples. The genotyping nanodevice could be developed for simultaneous and multiplex analysis of several oligonucleotides in a homogeneous solution by adjusting the recognition sequence, demonstrating its potential application in the rapid screening of multiple biomarkers.

A Smart DNA-Based Nanosystem Containing Ribosome-Regulating siRNA for Enhanced mRNA Transfection

Messenger RNA (mRNA) transfection is the prerequisite for the application of mRNA-based therapeutics. In hard-to-transfect cells, such as macrophages, the effective transfection of mRNA remains a long-standing challenge. Herein, a smart DNA-based nanosystem is reported containing ribosome biogenesis-promoting siRNA, realizing efficient mRNA transfection in macrophages. Four monomers are copolymerized to form a nanoframework (NF), including N-isopropylacrylamide (NIPAM) as the skeleton and acrydite-DNA as the initiator to trigger the cascade assembly of DNA hairpins (H1-polyT and H2-siRNA). By virtue of the phase transition characteristic of polymeric NIPAM, below the lower critical solution temperature (LCST, ≈34 °C), the NF swells to expose polyT sequences to hybridize with the polyA tail of mRNA. Above the LCST, the NF deswells to encapsulate mRNA. The disulfide bond in the NF responds to glutathione, triggering the disassembly of the nanosystem; the siRNA and mRNA are released in response to triphosadenine and RNase H. The siRNA down-regulates the expression of heat shock protein 27, which up-regulates the expression of phosphorylated ribosomal protein S6. The nanosystem shows satisfactory mRNA transfection and translation efficiency in a mouse model. It is envisioned that the DNA-based nanosystem will provide a promising carrier to deliver mRNA in hard-to-transfect cells and promote the development of mRNA-based therapeutics.

Supramolecular Modulation of Tumor Microenvironment through Pillar[5]arene-Based Host-Guest Recognition to Synergize Cancer Immunotherapy

Despite the tremendous breakthrough of immunotherapy, the low response rate and resistance of immune checkpoint inhibitors (ICIs) toward solid tumors occur frequently. A highly hypoxic tumor microenvironment (TME) provides tumor cells with high concentrations of HIF-1α and polyamines to evade immune cell destruction. Reprogramming of an immunogenic TME has exhibited a brilliant future to boost immunotherapeutic performances. Herein, a supramolecular nanomedicine (TAPP) is developed on the basis of host-guest molecular recognition and metal coordination, showing the capability to remodel the immunosuppressive TME. Tamoxifen (Tmx) and Fe3+ are encapsulated into TAPP to achieve the combination of chemotherapy and chemodynamic therapy (CDT). Tmx directly downregulates HIF-1α, and a pillar[5]arene-based macrocyclic host successfully eliminates polyamines in tumors. Enhanced immunogenic cell death is achieved by Tmx and Fe3+, and the therapeutic efficacy is further synergized by immune checkpoint blockade (ICB) therapy. This supramolecular reprogramming modality encourages cytotoxic T lymphocyte infiltration, achieving pre-eminent immune response and long-term tumor suppression.

Controllable mitochondrial aggregation and fusion by a programmable DNA binder

DNA nanodevices have been feasibly applied for various chemo-biological applications, but their functions as precise regulators of intracellular organelles are still limited. Here, we report a synthetic DNA binder that can artificially induce mitochondrial aggregation and fusion in living cells. The rationally designed DNA binder consists of a long DNA chain, which is grafted with multiple mitochondria-targeting modules. Our results indicated that the DNA binder-induced in situ self-assembly of mitochondria can be used to successfully repair ROS-stressed neuron cells. Meanwhile, this DNA binder design is highly programmable. Customized molecular switches can be easily implanted to further achieve stimuli-triggered mitochondrial aggregation and fusion inside living cells. We believe this new type of DNA regulator system will become a powerful chemo-biological tool for subcellular manipulation and precision therapy.

A DNA-based hydrogel for exosome separation and biomedical applications

Exosomes (EXOs) have been proven as biomarkers for disease diagnosis and agents for therapeutics. Great challenge remains in the separation of EXOs with high-purity and low-damage from complex biological media, which is critical for the downstream applications. Herein, we report a DNA-based hydrogel to realize the specific and nondestructive separation of EXOs from complex biological media. The separated EXOs were directly utilized in the detection of human breast cancer in clinical samples, as well as applied in the therapeutics of myocardial infarction in rat models. The materials chemistry basis of this strategy involved the synthesis of ultralong DNA chains via an enzymatic amplification, and the formation of DNA hydrogels through complementary base-pairing. These ultralong DNA chains that contained polyvalent aptamers were able to recognize and bind with the receptors on EXOs, and the specific and efficient binding ensured the selective separation of EXOs from media into the further formed networked DNA hydrogel. Based on this DNA hydrogel, rationally designed optical modules were introduced for the detection of exosomal pathogenic microRNA, which achieved the classification of breast cancer patients versus healthy donors with 100% precision. Furthermore, the DNA hydrogel that contained mesenchymal stem cell-derived EXOs was proved with significant therapeutic efficacy in repairing infarcted myocardium of rat models. We envision that this DNA hydrogel-based bioseparation system is promising as a powerful biotechnology, which will promote the development of extracellular vesicles in nanobiomedicine.

DNA hydrogels and nanogels for diagnostics, therapeutics, and theragnostics of various cancers

As an efficient class of hydrogel-based therapeutic drug delivery systems, deoxyribonucleic acid (DNA) hydrogels (particularly DNA nanogels) have attracted massive attention in the last five years. The main contributor to this is the programmability of these 3-dimensional (3D) scaffolds that creates fundamental effects, especially in treating cancer diseases. Like other active biological ingredients (ABIs), DNA hydrogels can be functionalized with other active agents that play a role in targeting drug delivery and modifying the half-life of the therapeutic cargoes in the body's internal environment. Considering the brilliant advantages of DNA hydrogels, in this survey, we intend to submit an informative collection of feasible methods for the design and preparation of DNA hydrogels and nanogels, and the responsivity of the immune system to these therapeutic cargoes. Moreover, the interactions of DNA hydrogels with cancer biomarkers are discussed in this account. Theragnostic DNA nanogels as an advanced species for both detection and therapeutic purposes are also briefly reviewed.

DNA Nanomaterials-Based Platforms for Cancer Immunotherapy

The past few decades have witnessed the evolving paradigm for cancer therapy from nonspecific cytotoxic agents to selective, mechanism-based therapeutics, especially immunotherapy. In particular, the integration of nanomaterials with immunotherapy is proven to improve the therapeutic outcome and minimize off-target toxicity in the treatment. As a novel nanomaterial, DNA-based self-assemblies featuring uniform geometries, feasible modifications, programmability, surface addressability, versatility, and intrinsic biocompatibility, are extensively exploited for innovative and effective cancer immunotherapy. In this review, the successful employment of DNA nanoplatforms for cancer immunotherapy, including the delivery of immunogenic cell death inducers, adjuvants and vaccines, immune checkpoint blockers as well as the application in immune cell engineering and adoptive cell therapy is summarized. The remaining challenges and future perspectives regarding the pharmacokinetics/pharmacodynamics, in vivo fate and immunogenicity of DNA materials, and the design of intelligent DNA nanomedicine for individualized cancer immunotherapy are also discussed.

A Smart Nano-Theranostic Platform Based on Dual-microRNAs Guided Self-Feedback Tetrahedral Entropy-Driven DNA Circuit

MicroRNAs (miRNAs) can act as oncogenes or tumor suppressors, capable of up or down-regulating gene expression during tumorigenesis; they are diagnostic biomarkers or therapeutic targets for tumors. To detect low abundance of intracellular oncogenic miRNAs (onco-miRNAs) and realize synergistic gene therapy of onco-miRNAs and tumor suppressors, a smart nano-theranostic platform based on dual-miRNAs guided self-feedback tetrahedral entropy-driven DNA circuit is created. The platform as a delivery vehicle is a DNA tetrahedral framework, in which the entropy-driven DNA circuit achieves a dual-miRNAs guided self-feedback, between an in situ amplification of the onco-miRNAs and activation of suppressor miRNAs release. To test this platform, dual-miRNAs are selected, miRNA-155, an up-regulated miRNA, as cancer indicators, and miRNA-122, a down-regulated miRNA as therapy targets in hepatocellular carcinoma, respectively. Through the circuit, the platform to detect onco-miRNAs at femtomolar level as well as visualized miRNAs inside cells, fixed tissues, and mice is programmed. Furthermore, triggered by miRNA-155, preloaded miRNA-122 is amplified via the self-feedback and released into target cells; the sudden increase of miRNA-122 and simultaneous decrease of miRNA-155 synergistically served as therapeutic drugs for gene regulation with enhanced antitumor efficacy and superior biosafety. It is envisioned that this nano-theranostic platform will initiate an essential step toward tumor theranostics in personalized/precise medicine.

Polymeric DNA Hydrogels and Their Applications in Drug Delivery for Cancer Therapy

The biomolecule deoxyribonucleic acid (DNA), which acts as the carrier of genetic information, is also regarded as a block copolymer for the construction of biomaterials. DNA hydrogels, composed of three-dimensional networks of DNA chains, have received considerable attention as a promising biomaterial due to their good biocompatibility and biodegradability. DNA hydrogels with specific functions can be prepared via assembly of various functional sequences containing DNA modules. In recent years, DNA hydrogels have been widely used for drug delivery, particularly in cancer therapy. Benefiting from the sequence programmability and molecular recognition ability of DNA molecules, DNA hydrogels prepared using functional DNA modules can achieve efficient loading of anti-cancer drugs and integration of specific DNA sequences with cancer therapeutic effects, thus achieving targeted drug delivery and controlled drug release, which are conducive to cancer therapy. In this review, we summarized the assembly strategies for the preparation of DNA hydrogels on the basis of branched DNA modules, hybrid chain reaction (HCR)-synthesized DNA networks and rolling circle amplification (RCA)-produced DNA chains, respectively. The application of DNA hydrogels as drug delivery carriers in cancer therapy has been discussed. Finally, the future development directions of DNA hydrogels in cancer therapy are prospected.

Assembly of Rolling Circle Amplification-Produced Ultralong Single-Stranded DNA to Construct Biofunctional DNA Materials

The Review by Yang, Yao and colleagues (DOI: 10.1002/chem.202202673) describes recent developments in biofunctional DNA hydrogels and DNA nanocomplexes based on rolling circle amplification (RCA) and introduces assembly strategies and functionalization methods of the ultralong single-strand DNA produced by RCA to construct biofunctional materials.

Stimuli-Responsive Self-Degradable DNA Hydrogels: Design, Synthesis, and Applications

DNA hydrogels play an increasingly important role in biomedicine and bioanalysis applications. Due to their high programmability, multifunctionality and biocompatibility, they are often used as effective carriers for packing drugs, cells, or other bioactive cargoes in vitro and in vivo. However, the stability of the DNA hydrogels prevents their in-demand rapid release of cargoes to achieve a full therapeutic effect in time. For bioanalysis, the generation of signals sometimes needs the DNA hydrogel to be rapidly degraded when sensing target molecules. To meet these requirements, stimulus-responsive DNA hydrogels are designed. By responding to different stimuli, self-degradable DNA hydrogels can switch from gel to solution for quantitative bioanalysis and precision cargo delivery. This review summarizes the recently developed innovative methods for designing stimuli-responsive self-degradable DNA hydrogels and showed their applications in the bioanalysis and biomedicines fields. Challenges, as well as prospects, are also discussed.

Advances in DNA Supramolecular Hydrogels for Tissue Engineering

Deoxyribonucleic acid (DNA) is a biological macromolecule that plays a genetic role in cells. DNA molecules with specific recognition, self-assembly capabilities, and sequence programmability have become an excellent construction material for micro- and nanostructures. Based on DNA self-assembly technology, a series of molecular devices and materials are constructed. Among them, DNA hydrogels with the advantages of good biocompatibility, biodegradability, and containing designable stimuli-responsive units have attracted much attention. This review introduces the formation strategy of DNA supramolecular hydrogels, and focuses on its applications in tissue engineering, including cell encapsulation, cell culture, cell capture and release, wound dressings, and tissue growth. The unique properties and application prospects of DNA supramolecular hydrogels in tissue engineering are also discussed.

Hydrogel-guided strategies to stimulate an effective immune response for vaccine-based cancer immunotherapy

Cancer vaccines have attracted widespread interest in tumor therapy because of the potential to induce an effective antitumor immune response. However, many challenges including weak immunogenicity, off-target effects, and immunosuppressive microenvironments have prevented their broad clinical translation. To overcome these difficulties, effective delivery systems have been designed for cancer vaccines. As carriers in cancer vaccine delivery systems, hydrogels have gained substantial attention because they can encapsulate a variety of antigens/immunomodulators and protect them from degradation. This enables hydrogels to simultaneously reverse immunosuppression and stimulate the immune response. Meanwhile, the controlled release properties of hydrogels allow for precise temporal and spatial release of loads in situ to further enhance the immune response of cancer vaccines. Therefore, this review summarizes the classification of cancer vaccines, highlights the strategies of hydrogel-based cancer vaccines, and provides some insights into the future development of hydrogel-based cancer vaccines.

Steering DNA Condensation on Engineered Nanointerfaces

DNA has received increasing attention in nanotechnology due to its ability to fold into prescribed structures. Different from the commonly adopted base-pairing strategy, an emerging class of amorphous DNA materials are formed by DNA's abiological interactions. Despite the great successes, a lack of nanoscale nucleation/growth control disables more advanced considerations. This work aims at harnessing the heterogeneous nucleation of metal-ion-glued DNA condensates on nanointerfaces. Upon unveiling key orthogonal factors including solution pH, ionic cross-linkers, and surface functionalities, chemically programmable DNA condensation on nanoparticle seeds is achieved, resembling a famous Stöber process for silica coating. The nucleation rules discovered on individual nanoseeds can be passed on to their dimeric assemblies, where broken spherical symmetry and the existence of interparticle gaps help a regiospecific DNA gelation. The steerable DNA condensation, and the multifunctions from DNA, metal ions, and nanocores, hold a great promise in noncanonical DNA nanotechnology toward novel applications.

Applications of Functional DNA Materials in Immunomodulatory Therapy

In recent years, nanoscale or microscale functional materials derived from DNA have shown great potential for immunotherapy as superior delivery carriers. DNA nanostructures with excellent programmability and addressability enable the precise assembly of molecules or nanoparticles. DNA hydrogels have predictable structures and adjustable mechanical strength, thus being advantageous in controllable release of cargos. In addition, utilizing systematic evolution of ligands by exponential enrichment technology, a variety of DNA aptamers have been screened for specific recognition of ions, molecules, and even cells. Moreover, a wide variety of chemical modifications can further enrich the function of DNA. The unique advantages of functional DNA materials make them extremely attractive in immunomodulation. Recently, functional DNA materials-based immunotherapy has shown great potential in fighting against many diseases like cancer, viral infection, and inflammation. Therefore, in this review, we focus on discussing the progress of the applications of functional DNA materials in immunotherapy; before that, we also summarize the characteristics of the functional DNA materials descried above. Finally, we discuss the challenges and future opportunities of functional DNA materials in immunomodulatory therapy.

Programmable DNA Hydrogels as Artificial Extracellular Matrix

The cell microenvironment plays a crucial role in regulating cell behavior and fate in physiological and pathological processes. As the fundamental component of the cell microenvironment, extracellular matrix (ECM) typically possesses complex ordered structures and provides essential physical and chemical cues to the cells. Hydrogels have attracted much attention in recapitulating the ECM. Compared to natural and synthetic polymer hydrogels, DNA hydrogels have unique programmable capability, which endows the material precise structural customization and tunable properties. This review focuses on recent advances in programmable DNA hydrogels as artificial extracellular matrix, particularly the pure DNA hydrogels. It introduces the classification, design, and assembly of DNA hydrogels, and then summarizes the state-of-the-art achievements in cell encapsulation, cell culture, and tissue engineering with DNA hydrogels. Ultimately, the challenges and prospects for cellular applications of DNA hydrogels are delivered.

A Biostable l-DNA Hydrogel with Improved Stability for Biomedical Applications

DNA hydrogels have attracted increasing attention owing to their excellent permeability and high mechanical strength, together with thixotropy, versatile programmability and good biocompatibility. However, the moderate biostability and immune stimulation of DNA have arisen as big concerns for future potential clinical applications. Herein, we report the self-assembly of a novel l-DNA hydrogel, which inherited the extraordinary physical properties of a d-DNA hydrogel. With the mirror-isomer deoxyribose, this hydrogel exhibited improved biostability, withstanding fetal bovine serum (FBS) for at least 1 month without evident decay of its mechanical properties. The low inflammatory response of the l-DNA hydrogel has been verified both in vitro and in vivo. Hence, this l-DNA hydrogel with outstanding biostability and biocompatibility can be anticipated to serve as an ideal 3D cell-culture matrix and implanted bio-scaffold for long-term biomedical applications.

DNA Supramolecular Assembly on Micro/Nanointerfaces for Bioanalysis

ConspectusFacing increasing demand for precision medicine, materials chemistry systems for bioanalysis with accurate molecular design, controllable structure, and adjustable biological activity are required. As a genetic biomacromolecule, deoxyribonucleic acid (DNA) is created via precise, efficient, and mild processes in life systems and can in turn precisely regulate life activities. From the perspective of materials chemistry, DNA possesses the characteristics of sequence programmability and can be endowed with customized functions by the rational design of sequences. In recent years, DNA has been considered to be a potential biomaterial for analysis and has been applied in the fields of bioseparation, biosensing, and detection imaging. To further improve the precision of bioanalysis, the supramolecular assembly of DNA on micro/nanointerfaces is an effective strategy to concentrate functional DNA modules, and thus the functions of DNA molecules for bioanalysis can be enriched and enhanced. Moreover, the new modes of DNA supramolecular assembly on micro/nanointerfaces enable the integration of DNA with the introduced components, breaking the restriction of limited functions of DNA materials and achieving more precise regulation and manipulation in bioanalysis. In this Account, we summarize our recent work on DNA supramolecular assembly on micro/nanointerfaces for bioanalysis from two main aspects. In the first part, we describe DNA supramolecular assembly on the interfaces of microscale living cells. The synthesis strategy of DNA is based on rolling-circle amplification (RCA), which generates ultralong DNA strands according to circular DNA templates. The templates can be designed with complementary sequences of functional modules such as aptamers, which allow DNA to specifically bind with cellular interfaces and achieve efficient cell separation. In the second part, we describe DNA supramolecular assembly on the interfaces of nanoscale particles. DNA sequences are designed with functional modules such as targeting, drug loading, and gene expression and then are assembled on interfaces of particles including upconversion nanoparticles (UCNPs), gold nanoparticles (AuNPs), and magnetic nanoparticle (MNPs). The integration of DNA with these functional particles achieves cell manipulation, targeted tumor imaging, and cellular regulation. The processes of interfacial assembly are well controlled, and the functions of the obtained bioanalytical materials can be flexibly regulated. We envision that the work on DNA supramolecular assembly on micro/nanointerfaces will be a typical paradigm for the construction of more bioanalytical materials, which we hope will facilitate the development of precision medicine.

The interactions between DNA nanostructures and cells: A critical overview from a cell biology perspective

DNA nanotechnology has yielded remarkable advances in  composite materials with diverse applications in biomedicine. The specificity and predictability of building 3D structures at the nanometer scale make DNA nanotechnology a promising tool for uses in biosensing, drug delivery, cell modulation, and bioimaging. However, for successful translation of DNA nanostructures to real-world applications, it is crucial to understand how they interact with living cells, and the consequences of such interactions. In this review, we summarize the current state of knowledge on the interactions of DNA nanostructures with cells. We identify key challenges, from a cell biology perspective, that influence progress towards the clinical translation of DNA nanostructures. We close by providing an outlook on what questions must be addressed to accelerate the clinical translation of DNA nanostructures. STATEMENT OF SIGNIFICANCE: Self-assembled DNA nanostructures (DNs) offers unique opportunities to overcome persistent challenges in the nanobiotechnology field. However, the interactions between engineered DNs and living cells are still not well defined. Critical systematization of current cellular models and biological responses triggered by DNs is a crucial foundation for the successful clinical translation of DNA nanostructures. Moreover, such an analysis will identify the pitfalls and challenges that are present in the field, and provide a basis for overcoming those challenges.

Injectable DNA Hydrogel-Based Local Drug Delivery and Immunotherapy

Regulated drug delivery is an important direction in the field of medicine and healthcare research. In recent years, injectable hydrogels with good biocompatibility and biodegradability have attracted extensive attention due to their promising application in controlled drug release. Among them, DNA hydrogel has shown great potentials in local drug delivery and immunotherapy. DNA hydrogel is a three-dimensional network formed by cross-linking of hydrophilic DNA strands with extremely good biocompatibility. Benefiting from the special properties of DNA, including editable sequence and specificity of hybridization reactions, the mechanical properties and functions of DNA hydrogels can be precisely designed according to specific applications. In addition, other functional materials, including peptides, proteins and synthetic organic polymers can be easily integrated with DNA hydrogels, thereby enriching the functions of the hydrogels. In this review, we first summarize the types and synthesis methods of DNA hydrogels, and then review the recent research progress of injectable DNA hydrogels in local drug delivery, especially in immunotherapy. Finally, we discuss the challenges facing DNA hydrogels and future development directions.

A high-integrated DNA biocomputing platform for MicroRNA sensing in living cells

DNA logic computing has captured increasing interest due to its ability to assemble programmable DNA computing elements for disease diagnosis, gene regulation, and targeted therapy. In this work, we developed an aptamer-equipped high-integrated DNA biocomputing platform (HIDBP-A) with a dual-recognition function that enabled cancer cell targeting. Dual microRNAs were the input signals and can perform AND logic operations. Compared to the free DNA biocomputing platform (FDBP), the integration of all computing elements into the same DNA tetrahedron greatly improved logic computing speed and efficiency owing to the confinement effect reflected by the high local concentration of computing elements. As a proof of concept, the utilization of microRNA as the input signal was beneficial for improving the scalability and flexibility of the sequence design of the logic nano-platform. Given that the different microRNAs were over-expressed in cancer cells, this new HIDBP-A has great promise in accurate diagnosis and logic-controlled disease treatment.

Application of Nucleic Acid Frameworks in the Construction of Nanostructures and Cascade Biocatalysts: Recent Progress and Perspective

Nucleic acids underlie the storage and retrieval of genetic information literally in all living organisms, and also provide us excellent materials for making artificial nanostructures and scaffolds for constructing multi-enzyme systems with outstanding performance in catalyzing various cascade reactions, due to their highly diverse and yet controllable structures, which are well determined by their sequences. The introduction of unnatural moieties into nucleic acids dramatically increased the diversity of sequences, structures, and properties of the nucleic acids, which undoubtedly expanded the toolbox for making nanomaterials and scaffolds of multi-enzyme systems. In this article, we first introduce the molecular structures and properties of nucleic acids and their unnatural derivatives. Then we summarized representative artificial nanomaterials made of nucleic acids, as well as their properties, functions, and application. We next review recent progress on constructing multi-enzyme systems with nucleic acid structures as scaffolds for cascade biocatalyst. Finally, we discuss the future direction of applying nucleic acid frameworks in the construction of nanomaterials and multi-enzyme molecular machines, with the potential contribution that unnatural nucleic acids may make to this field highlighted.

A CRISPR/Cas12a-responsive dual-aptamer DNA network for specific capture and controllable release of circulating tumor cells

The separation and detection of circulating tumor cells (CTCs) have a significant impact on clinical diagnosis and treatment by providing a predictive diagnosis of primary tumors and tumor metastasis.