Self-Assembly of Dendritic DNA into a Hydrogel: Application in Three-Dimensional Cell Culture

From leaf to lab-on-cloth: Spatial DNA nanorobotics and 2D graphyne synergy enable ultra-precise electrochemical tracking of sugarcane pokkah boeng disease

As a vital cash crop and bioenergy feedstock, sugarcane plays a pivotal role in global agriculture and renewable energy systems. The emergence of pokkah boeng disease has become a critical threat to sugarcane productivity. Current diagnostic methods face challenges in field-applicable early detection due to time-consuming procedures and insufficient sensitivity. This study pioneers a "Lab-on-Cloth" electrochemical biosensor that synergizes DNA nanorobotics with 2D graphyne for ultra-precise detecting of pathogen. The biosensor integrates three synergistic innovation mechanisms: a spatially confined DNA Walker system enabling programmable strand displacement cascades upon target recognition, sulfur-doped graphyne (S-GDY) nanoarrays providing enhanced electron transfer efficiency and catalytic current density, and a dual-signal readout strategy for self-verifying detection accuracy. The biosensor fabrication involves in fixing of AuNPs/S-GDY heterostructures on flexible carbon cloth, creating a hierarchical 3D conductive network. Upon pathogen DNA binding, the DNA Walker initiates dual strand displacement amplification cycles, generating distinct current responses through potential-resolved signal decoupling. This dual-signal readout achieves an ultra-low limit of detection (16.6 aM, S/N = 3) with a dynamic range spanning six orders of magnitude (0.1 fM-10 nM), outperforming conventional qPCR in field tests. This spatial DNA nanorobotics-graphyne synergy establishes a new paradigm for plant disease monitoring, providing real-time phyto-diagnostic capabilities. The technology's cost-effectiveness and operational simplicity position it as a transformative tool for precision agriculture and sustainable bioenergy production.

DNA as a promising biomaterial for bone regeneration and potential mechanisms of action

DNA nanotechnology has created new possibilities for the use of DNA in tissue regeneration - an important advance for DNA use beyond its paradigmatic role as the hereditary biomacromolecule. Biomaterials containing synthetic or natural DNA have been proposed for several applications including drug and gene delivery, and more recently, as osteoconductive biomaterials. This review provides an in-depth discussion of studies that have used DNA-based materials for biomineralization and/or bone repair, with expansion on the topic of DNA hydrogels specifically, and the advantages they offer for advancing the field of bone regeneration. Four mechanisms of action for the osteoconductive capabilities of DNA-based materials are discussed, and a proposed model for degradation of these materials and its link to their osteoconductive properties is later presented. Finally, the review considers current limitations of DNA-based materials and summarizes important aspects that need to be addressed for future application of DNA nanotechnology in tissue repair. STATEMENT OF SIGNIFICANCE: Herein we summarize the developing field of DNA-based materials for biomineralization and bone repair, with a focus on DNA hydrogels. We first provide a comprehensive review of different forms of DNA-based materials described thus far which have been shown to enhance bone repair and mineralization (namely DNA coatings, DNA-containing pastes, DNA nanostructures and DNA hydrogels). Next, we describe four different mechanisms by which DNA-based materials could be exerting their osteogenic effect. Then, we propose a novel model that links DNA degradation and osteoconductivity. Lastly, we suggest possible research directions to enhance DNA-based materials for future clinical application. The suggested mechanisms and the proposed model can guide future research to better understand how DNA functions as a mineral- and bone-promoting molecule.

DNA Hydrogels in Tissue Engineering: From Molecular Design to Next-Generation Biomedical Applications

DNA hydrogels have emerged as promising materials in tissue engineering due to their biocompatibility, programmability, and responsiveness to stimuli. Synthesized through physical and chemical crosslinking, these hydrogels can be categorized into functionalized types, such as those based on aptamers, and stimuli-responsive types that react to pH, temperature, and light. This review highlights their applications in tissue engineering, including drug delivery, cell culture, biosensing, and gene editing. DNA hydrogels can encapsulate therapeutic agents, support cell growth, and respond dynamically to environmental changes, making them ideal for tissue engineering. A comprehensive bibliometric analysis is included, identifying key research trends and emerging areas of interest in DNA hydrogel design, synthesis, and biomedical applications. The analysis provides a deeper understanding of the field's development and future research directions. Challenges such as mechanical strength, stability, and biosafety persist, but the integration of AI in hydrogel design shows promise for advancing their functionality in clinical applications.

DNA-encoded dynamic hydrogels for 3D bioprinted cartilage organoids

Articular cartilage, composed of chondrocytes within a dynamic viscoelastic matrix, has limited self-repair capacity, posing a significant challenge for regeneration. Constructing high-fidelity cartilage organoids through three-dimensional (3D) bioprinting to replicate the structure and physiological functions of cartilage is crucial for regenerative medicine, drug screening, and disease modeling. However, commonly used matrix bioinks lack reversible cross-linking and precise controllability, hindering dynamic cellular regulation. Thus, encoding bioinks adaptive for cultivating cartilage organoids is an attractive idea. DNA, with its ability to be intricately encoded and reversibly cross-linked into hydrogels, offers precise manipulation at both molecular and spatial structural levels. This endows the hydrogels with viscoelasticity, printability, cell recognition, and stimuli responsiveness. This paper elaborates on strategies to encode bioink via DNA, emphasizing the regulation of predictable dynamic properties and the resulting interactions with cell behavior. The significance of these interactions for the construction of cartilage organoids is highlighted. Finally, we discuss the challenges and future prospects of using DNA-encoded hydrogels for 3D bioprinted cartilage organoids, underscoring their potential impact on advancing biomedical applications.

Clickable immune-microenvironment modulated hydrogels for spinal cord injury repair

Spinal cord injury (SCI) is a devastating condition without effective therapy currently available. The inflammatory cascade following SCI leads to neuronal apoptosis and glial cell activation. The utilization of local injectable hydrogels with immunotherapy drugs directly into injured nerve tissues represents a promising therapeutic strategy. Herein, injectable hydrogels grafted with clickable methylprednisolone (MP) and cellular adhesion peptide were developed using free radical polymerization for promoting nerve regeneration following SCI. MP conjugated hydrogels could modulate the immunoinflammatory microenvironment of SCI and sustain neuron survival. The multi-stiffness hydrogels were fabricated by adjusting concentration ratios to evaluate appropriate mechanical stimuli. In a model of dorsal root ganglion, MP grafted hydrogels with mechanical signals similar to those of adult rat spinal cords demonstrated superior efficacy in promoting dorsal root ganglion growth. MP grafted hydrogels could regulate the immune-inflammatory microenvironment, promote recovery of both motor function and sensory functions. The positive findings suggested that the interplay between immunomodulation and mechanical signals plays a crucial role in promoting nerve regeneration, indicating significant potential for hydrogels as a therapeutic approach for repairing SCI.

Enhancing efficiency and control in DNA hydrogel synthesis: A dual rolling circle amplification approach and parameter optimization study

DNA hydrogels are a focus of current research in the realm of cutting-edge functional biomaterials. Rolling circle amplification (RCA) technology has surfaced as a flexible approach for producing functional DNA hydrogels in a one-pot manner, owing to its effectiveness and ease of use. This study introduces a simple dual RCA approach for producing DNA hydrogels. Our research delves into the impacts of different reaction parameters, such as reaction buffer, ethylenediaminetetraacetic acid (EDTA) concentration, base pair types and ratios, circular DNA template concentration, and RCA temperature, on the yield, morphology, and rheological characteristics of the resulting DNA hydrogels. Our findings demonstrate that DNA hydrogels prepared with TE buffer containing 1 mM EDTA, higher concentrations of circular DNA templates, and an RCA reaction temperature of 30 °C exhibited improved morphological characteristics and favorable mechanical properties. Furthermore, while G-C base pairs significantly enhance the mechanical properties of the hydrogel at lower concentrations, their excessive presence may negatively impact both the formation and mechanical integrity of the hydrogel. The findings from this study are crucial for boosting the efficiency and cost-effectiveness of DNA hydrogel synthesis, enhancing their quality, and broadening their range of applications.

Programmable soft DNA hydrogels stimulate cellular endocytic pathways and proliferation

Hydrogels are pivotal in tissue engineering, regenerative medicine, and drug delivery applications. Existing hydrogel platforms are not easily customizable and often lack precise programmability, making them less suited for 3D tissue culture and programming of cells. DNA molecules stand out among other promising biomaterials due to their unparalleled precision, programmability, and customization. In this study, we introduced a palette of novel cellular scaffolding platforms made of pure DNA-based hydrogel systems while improving the shortcomings of the existing platforms. We showed a quick and easy one step synthesis of DNA hydrogels using thermal annealing based on sequence specific hybridization strategy. We also demonstrated the formation of multi-armed branched supramolecular scaffolds with custom mechanical stiffness, porosity, and network density by increasing or decreasing the number of branching arms. These mechanically tuneable DNA hydrogels proved to be a suitable suitable platform for modulating the physiological processes of retinal pigment epithelial cells (RPE1). In-vitro studies showed dynamic changes at multiple levels, ranging from a change in morphology to protein expression patterns, enhanced membrane traffic, and proliferation. The soft DNA hydrogels explored here are mechanically compliant and pliable, thus excellently suited for applications in cellular programming and reprogramming. This research lays the groundwork for developing a DNA hydrogel system with a higher dynamic range of stiffness, which will open exciting avenues for tissue engineering and beyond.

Programmable Artificial Skins Accomplish Antiscar Healing with Multiple Appendage Regeneration

Functional appendage regeneration is essential for skin rehabilitation, but it has always failed by current existing healing approaches, owing to their inefficacy in preventing disfiguring scars. In this study, a novel regeneration-directing artificial skin (RDAS) system is presented, which is based on the rational design of multi-layered hydrogels that closely mimic natural skin matrices. By leveraging the programmability and architectural rigidity of DNA components, without the need for exogenous cell transplantation, such RDAS effectively minimizes tissue fibrosis by accurately guiding the regenerative process in wound fibroblasts, enabling rapid scarless wound repair, restoration of dermal function, and successful in situ regeneration of multiple appendages, such as hair follicles (HFs), sebaceous glands (SGs), and sweat glands (SwGs). Therefore, the RDAS offers a cell-free antiscarring therapeutic strategy for regenerative wound healing, resulting in improved outcomes. This innovative approach holds great potential for future clinical applications and burn rehabilitation.

Synthetic Nanoassemblies for Regulating Organelles: From Molecular Design to Precision Therapeutics

Each organelle referring to a complex multiorder architecture executes respective biological processes via its distinct spatial organization and internal microenvironment. As the assembly of biomolecules is the structural basis of living cells, creating synthetic nanoassemblies with specific physicochemical and morphological properties in living cells to interfere or couple with the natural organelle architectures has attracted great attention in precision therapeutics of cancers. In this review, we give an overview of the latest advances in the synthetic nanoassemblies for precise organelle regulation, including the formation mechanisms, triggering strategies, and biomedical applications in precision therapeutics. We summarize the emerging material systems, including polymers, peptides, and deoxyribonucleic acids (DNAs), and their respective intermolecular interactions for intercellular synthetic nanoassemblies, and highlight their design principles in constructing precursors that assemble into synthetic nanoassemblies targeting specific organelles in the complex cellular environment. We further showcase the developed intracellular synthetic nanoassemblies targeting specific organelles including mitochondria, the endoplasmic reticulum, lysosome, Golgi apparatus, and nucleus and describe their underlying mechanisms for organelle regulation and precision therapeutics for cancer. Last, the essential challenges in this field and prospects for future precision therapeutics of synthetic nanoassemblies are discussed. This review should facilitate the rational design of organelle-targeting synthetic nanoassemblies and the comprehensive recognition of organelles by materials and contribute to the deep understanding and application of the synthetic nanoassemblies for precision therapeutics.

Advancing Synthetic Hydrogels through Nature-Inspired Materials Chemistry

Synthetic extracellular matrix (ECM) mimics that can recapitulate the complex biochemical and mechanical nature of native tissues are needed for advanced models of development and disease. Biomedical research has heavily relied on the use of animal-derived biomaterials, which is now impeding their translational potential and convoluting the biological insights gleaned from in vitro tissue models. Natural hydrogels have long served as a convenient and effective cell culture tool, but advances in materials chemistry and fabrication techniques now present promising new avenues for creating xenogenic-free ECM substitutes appropriate for organotypic models and microphysiological systems. However, significant challenges remain in creating synthetic matrices that can approximate the structural sophistication, biochemical complexity, and dynamic functionality of native tissues. This review summarizes key properties of the native ECM, and discusses recent approaches used to systematically decouple and tune these properties in synthetic matrices. The importance of dynamic ECM mechanics, such as viscoelasticity and matrix plasticity, is also discussed, particularly within the context of organoid and engineered tissue matrices. Emerging design strategies to mimic these dynamic mechanical properties are reviewed, such as multi-network hydrogels, supramolecular chemistry, and hydrogels assembled from biological monomers.

Responsive DNA hydrogels: design strategies and prospects for biosensing

Hydrogels, water-filled networks that can adapt to external stimuli by altering their volume, are known for their high flexibility and biocompatibility. DNA, a critical biomolecule renowned for its exceptional characteristics including information transmission, molecular recognition, and editability, has found widespread applications in the biosensing field as well. The integration of these two biomaterials offers promising opportunities for the development of novel biosensors with enhanced sensitivity, specificity, and adaptability. Therefore, by virtue of the collective features, researchers have recently focused on the construction of responsive DNA hydrogel systems. This feature article describes recent developments in fabricating DNA hydrogels and their applications in the biosensing area. Initially, it focuses on the design strategies employed in preparing DNA hydrogels, encompassing both pure DNA hydrogels and hybridized DNA hydrogels. Subsequently, it summarizes the use of DNA hydrogels in biosensing applications, highlighting their applications in visual detection, electrochemical sensing, and optical biosensing analyses. Furthermore, the underlying responsive mechanisms within these biosensing systems are also described. Lastly, this article presents a comprehensive discussion on the existing challenges and prospects of responsive DNA hydrogels, offering insights into their potential to revolutionize the field of biosensing.

Acrylate-Based PEG Hydrogels with Ultrafast Biodegradability for 3D Cell Culture

Poly(ethylene glycol) (PEG)-based hydrogels are particularly challenging to degrade, which hinders efficient cell harvesting within the gel matrix. Here, highly branched copolymers of PEG methyl ether acrylate (PEGMA) and disulfide diacrylate (DSDA) (PEG-DS) with short primary chains and multiple pendent vinyl groups were synthesized by a "vinyl oligomer combination" approach. PEG-DS readily cross-links with thiolated gelatin (Gel-SH) to form hydrogels. Results demonstrate that shortening the primary chains of PEG-DS significantly enhances the viability of bone marrow mesenchymal stem cells (BMSCs) by up to 193.2%. Importantly, DS junctions can be easily cleaved into short primary chains using dithiothreitol (DTT), triggering ultrafast degradation of PEG-DS/Gel-SH hydrogels within 2 min under mild conditions and release of the encapsulated BMSCs. This study establishes a novel strategy to enhance the degradation of acrylate-based PEG hydrogels for three-dimensional (3D) cell culture and harvesting. These findings expand the potential applications of such hydrogels in various biomedical fields.

Harnessing the potential of hydrogels for advanced therapeutic applications: current achievements and future directions

The applications of hydrogels have expanded significantly due to their versatile, highly tunable properties and breakthroughs in biomaterial technologies. In this review, we cover the major achievements and the potential of hydrogels in therapeutic applications, focusing primarily on two areas: emerging cell-based therapies and promising non-cell therapeutic modalities. Within the context of cell therapy, we discuss the capacity of hydrogels to overcome the existing translational challenges faced by mainstream cell therapy paradigms, provide a detailed discussion on the advantages and principal design considerations of hydrogels for boosting the efficacy of cell therapy, as well as list specific examples of their applications in different disease scenarios. We then explore the potential of hydrogels in drug delivery, physical intervention therapies, and other non-cell therapeutic areas (e.g., bioadhesives, artificial tissues, and biosensors), emphasizing their utility beyond mere delivery vehicles. Additionally, we complement our discussion on the latest progress and challenges in the clinical application of hydrogels and outline future research directions, particularly in terms of integration with advanced biomanufacturing technologies. This review aims to present a comprehensive view and critical insights into the design and selection of hydrogels for both cell therapy and non-cell therapies, tailored to meet the therapeutic requirements of diverse diseases and situations.

DNA Polymerase-Endonuclease Efficiently Synthesizes DNA to Prepare DNA Materials and Develop Novel Signal Amplification System

DNA biosynthesis, a focus of fundamental and applied research, typically involves DNA polymerases by using templates, primers, and dNTPs. Some polymerases can polymerize dNTPs for DNA de novo synthesis, although this is generally to occur randomly. This novel synthesis method has garnered our attention and practical use. Herein, we observed that the addition of endonuclease significantly enhances the efficiency of the de novo synthesis reaction catalyzed by the DNA polymerase. We further investigated the reaction conditions that influence this efficiency. Building on the optimal reaction conditions, we developed a rapid and efficient strategy for preparing DNA hydrogel. Further, coupled with the CRISPR-Cas system, we developed a nucleic acid signal amplification system characterized by versatility, sensitivity, specificity, and no risk of aerosol contamination. We successfully detected viral nucleic acids in clinical samples. In summary, our study demonstrates the significant potential of DNA polymerase- and endonuclease-catalyzed DNA de novo synthesis in diverse applications.

Exploring the Landscape of Hydrogel Therapy for Spinal Cord Injury: A Bibliometric and Visual Analysis (1991-2023)

BACKGROUND

This study aimed to conduct a bibliometric analysis of the literature on hydrogel therapy for spinal cord injury to visualize the research status, identify hotspots, and explore the development trends in this field.

METHODS

Web of science Core Collection database was searched for relevant studies published between January 1991 and December 2023. Data such as journal title, author information, institutional affiliation, country, citation, and keywords were extracted. Bibliometrix, CiteSpace, and VOSviewer were used to perform bibliometric analysis of the retrieved data.

RESULTS

A total of 1099 articles pertaining to hydrogel therapy for spinal cord injury were retrieved, revealing an upward trajectory in both annual publication volume and cumulative publication volume. Biomaterials emerged as the journal with the highest number of publications and the most rapid cumulative publication growth, contributing 84 articles. Among authors, Shoichet MS stood out with the highest number of publications and citations, totaling 66 articles. The University of Toronto led in institutional contributions with 65 publications, while China dominated in country-specific publications, accounting for 374 articles. However, to foster significant academic achievements, it is imperative for diverse authors, institutions, and countries to enhance collaboration. Current research in this field concentrates on scaffold architecture, nerve growth factor, the fibrotic microenvironment, and guidance channels. Simultaneously, upcoming research directions prioritize 3D bioprinting, injectable hydrogel, inflammation, and nanoparticles within the realm of hydrogel therapy for spinal cord injuries.

CONCLUSIONS

In summary, this study provided a comprehensive analysis of the current research status and frontiers of hydrogel therapy for spinal cord injury. The findings provide a foundation for future research and clinical translation efforts of hydrogel therapy in this field.

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.

Dual-functional DNA nanogels for anticancer drug delivery

DNA hydrogels with unique sequence programmability on nucleic acid framework manifest remarkable attributes, such as high payload capacities, biocompatibility and biosafety. The availability of DNA nanogels with multimodal functionalities remains limited due to the absence of facile gelation methods applicable at the nanometer scale. Here, we developed a one-step assembly of DNA dendrimers into nanogels (DNG) with couple hundred nanometers size. DNG showed robust stability against physical forces and biological degradation for easy purification and sustainable drug release. Long-term stability either in powder or aqueous solution endows DNG easy for shipping, handling and storage. By encoding dual functionalities into separate branches on DNA dendrimers, DNG can accommodate chemodrugs and aptamers with distinctive loading moduli. DNG significantly enhanced the drug efficacy against cancerous cells while minimizing cytotoxicity towards somatic cells, as demonstrated in vitro and in xenografted mice models of breast cancer. Thus, due to their facile assembly and storage, bi-entity encoding, and inherent biocompatibility, DNG exhibits immense prospects as nanoscale vesicles for the synergistic delivery of multimodal theranostics in anticancer treatments. STATEMENT OF SIGNIFICANCE: DNA nanogels were self-assembled via a facile protocol utilizing a DNA dendrimer structure. These nanogels displayed robust stability against physical forces, permitting long term storage in concentrated solutions or as a powder. Furthermore, they exhibited resilience to biological degradation, facilitating sustained drug release. The bi-entity encoded dendritic branches conferred dual functionalities, enabling both chemodrug encapsulation and the presentation of aptamers as targeting motifs. In vivo investigations confirmed the nanogels provide high efficacy in tumor targeting and chemotherapy with enhanced drug efficacy and reduced side effects.

Photo-Controllable Smart Hydrogels for Biomedical Application: A Review

Nowadays, smart hydrogels are being widely studied by researchers because of their advantages such as simple preparation, stable performance, response to external stimuli, and easy control of response behavior. Photo-controllable smart hydrogels (PCHs) are a class of responsive hydrogels whose physical and chemical properties can be changed when stimulated by light at specific wavelengths. Since the light source is safe, clean, simple to operate, and easy to control, PCHs have broad application prospects in the biomedical field. Therefore, this review timely summarizes the latest progress in the PCHs field, with an emphasis on the design principles of typical PCHs and their multiple biomedical applications in tissue regeneration, tumor therapy, antibacterial therapy, diseases diagnosis and monitoring, etc. Meanwhile, the challenges and perspectives of widespread practical implementation of PCHs are presented in biomedical applications. This study hopes that PCHs will flourish in the biomedical field and this review will provide useful information for interested researchers.

Exo I signal amplification of a DNA hydrogel film combined with capillary self-driven action for EpCAM detection

Target-responsive aptamer hydrogels are increasingly used in the field of analytical sensing with different morphologies developed by various strategies. Herein, we developed a DNA hydrogel film combined with capillary self-driven action for the specific detection of the tumor marker EpCAM and further introduced Exo I for signal amplification. EpCAM aptamer was used as a crosslinking agent to construct the DNA hydrogel film. When EpCAM was present, it competed for binding with the EpCAM aptamer, resulting in a permeability change of the DNA hydrogel film attached to one end of the capillary, and leading to different solution flow rates through the capillaries that can be utilized for the quantitative detection of EpCAM. This method did not require any instrument and was easy to use. The distance the solution travelled through the capillary was quantified as the concentration of EpCAM, and only a small amount of DNA hydrogel was required for each detection. The detection limit of EpCAM was as low as 0.018 ng mL-1, while offering the advantages of good stability and specificity, and showing great potential in point-of-care testing.

Programmable DNA Hydrogel Provides Suitable Microenvironment for Enhancing TSPCS Therapy in Healing of Tendinopathy

Tendon stem/progenitor cells (TSPCs) therapy is a promising strategy for enhancing cell matrix and collagen synthesis, and regulating the metabolism of the tendon microenvironment during tendon injury repair. Nevertheless, the barren microenvironment and gliding shear of tendon cause insufficient nutrition supply, damage, and aggregation of injected TSPCs around tendon tissues, which severely hinders their clinical application in tendinopathy. In this study, a TSPCs delivery system is developed by encapsulating TSPCs within a DNA hydrogel (TSPCs-Gel) as the DNA hydrogel offers an excellent artificial extracellular matrix (ECM) microenvironment by providing nutrition for proliferation and protection against shear forces. This delivery method restricts TSPCs to the tendons, significantly extending their retention time. It is also found that TSPCs-Gel injections can promote the healing of rat tendinopathy in vivo, where cross-sectional area and load to failure of injured tendons in rats are significantly improved compared to the free TSPCs treatment group at 8 weeks. Furthermore, the potential healing mechanism of TSPCs-Gel is investigated by RNA-sequencing to identify a series of potential gene and signaling pathway targets for further clinical treatment strategies. These findings suggest the potential pathways of using DNA hydrogels as artificial ECMs to promote cell proliferation and protect TSPCs in TSPC therapy.

Implementation of blood-brain barrier on microfluidic chip: recent advance and future prospects

The complex structure of the blood-brain barrier (BBB) hinders its modeling and the treatment of brain diseases. The microfluidic technology promotes the development of BBB-on-a-chip platforms, which can be used to reproduce the complex brain microenvironment and physiological reactions. Compared with traditional transwell technology, microfluidic BBB-on-a-chip shows great technical advantages in terms of flexible control of fluid shear stress in the chip and fabrication efficiency of the chip system, which can be enhanced by the development of lithography and three-dimensional (3D) printing. It is convenient to accurately monitor the dynamic changes of biochemical parameters of individual cells in the model by integrating an automatic super-resolution imaging sensing platform. In addition, biomaterials, especially hydrogels and conductive polymers, solve the limitations of microfluidic BBB-on-a-chip by compounding onto microfluidic chip to provide a 3D space and special performance on the microfluidic chip. The microfluidic BBB-on-a-chip promotes the development of basic research, including cell migration, mechanism exploration of neurodegenerative diseases, drug barrier permeability, SARS-CoV-2 pathology. This study summarizes the recent advances, challenges and future prospects of microfluidic BBB-on-a-chip, which can help to promote the development of personalized medicine and drug discovery.

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.

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.

Inhibition of Bacteria In Vitro and In Vivo by Self-Assembled DNA-Silver Nanocluster Structures

Antimicrobial nanomaterials hold great promise for bacteria-infected wound healing. However, it remains a challenge to balance antimicrobial efficacy and biocompatibility for these artificial antimicrobials. Here we employed biocompatible genetic molecule DNA as a building material to fabricate antimicrobial materials, including self-assembled Y-shaped DNA-silver nanocluster composite (Y-Ag) and Y-Ag hydrogel (Y-Ag-gel). We demonstrate that macroscopic and microcosmic DNA-Ag composites can effectively inhibit bacterial growth but do not affect cell proliferation in vitro. In particular, Y-Ag spray can speed up the process of wound healing in vivo. Considering the efficacy and advantages of DNA-based materials, our findings provide a promising route to fabricate a novel wound dressing such as spray and hydrogel for therapeutic wound healing.

Application of aptamers in regenerative medicine

Regenerative medicine is a discipline that studies how to use biological and engineering principles and operation methods to repair and regenerate damaged tissues and organs. Until now, regenerative medicine has focused mainly on the in-depth study of the pathological mechanism of diseases, the further development and application of new drugs, and tissue engineering technology strategies. The emergence of aptamers has supplemented the development methods and types of new drugs and enriched the application elements of tissue engineering technology, injecting new vitality into regenerative medicine. The role and application status of aptamers screened in recent years in various tissue regeneration and repair are reviewed, and the prospects and challenges of aptamer technology are discussed, providing a basis for the design and application of aptamers in long-term transformation.

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.

DNA Hydrogels in the Perspective of Mechanical Properties

Tailoring the mechanical properties has always been a key to the field of hydrogels in terms of different applications. Particularly, deoxyribonucleic acid (DNA) hydrogels offer an unambiguous way to precisely tune the mechanical properties, largely on account of their programmable sequences, abundant responding toolbox, and various ligation approaches. In this review, DNA hydrogels from the perspective of mechanical properties, from synthetic standpoint to different applications are introduced. The relationship between the structure and their mechanical properties in DNA hydrogels and the methods of regulating the mechanical properties of DNA hydrogels are specifically summarized. Furthermore, several recent applications of DNA hydrogels in relation to their mechanical properties are discussed. Benefiting from the tunability and flexibility, rational design of mechanical properties in DNA hydrogels provided unheralded interest from fundamental science to extensive applications. This article is protected by copyright. All rights reserved.

DNA Nanotechnology-Based Supramolecular Assemblies for Targeted Biomedical Applications

DNA is a polyanionic, hydrophilic, and natural biopolymer that offers properties such as biodegradability, biocompatibility, non-toxicity, and non-immunogenicity. These properties of DNA as an ideal biopolymer offer modern-day researchers' reasons to exploit these to form high-order supramolecular assemblies. These structures could range from simple to complex and provide various applications. Among them, supramolecular assemblies like DNA hydrogels (DNA-HG) and DNA dendrimers (DNA-DS) show massive growth potential in the areas of biomedical applications such as cell biology, medical stream, molecular biology, pharmacology, and healthcare product manufacturing. The application of both of these assemblies has seen enormous growth in recent years. In this focused review on DNA-based supramolecular assemblies like hydrogels and dendrimers, we present the principles of synthesis and characterization, key developments with examples and applications, and conclude with a brief perspective on challenges and future outlook for such devices and their subsequent applications.

Strategies to Modulate the Redifferentiation of Chondrocytes

Because of the low self-healing capacity of articular cartilage, cartilage injuries and degenerations triggered by various diseases are almost irreversible. Previous studies have suggested that human chondrocytes cultured in vitro tend to dedifferentiate during the cell-amplification phase and lose the physiological properties and functions of the cartilage itself, which is currently a critical limitation in the cultivation of cartilage for tissue engineering. Recently, numerous studies have focused on the modulation of chondrocyte redifferentiation. Researchers discovered the effect of various conditions (extracellular environment, cell sources, growth factors and redifferentiation inducers, and gene silencing and overexpression) on the redifferentiation of chondrocytes during the in vitro expansion of cells, and obtained cartilage tissue cultured in vitro that exhibited physiological characteristics and functions that were similar to those of human cartilage tissue. Encouragingly, several studies reported positive results regarding the modulation of the redifferentiation of chondrocytes in specific conditions. Here, the various factors and conditions that modulate the redifferentiation of chondrocytes, as well as their limitations and potential applications and challenges are reviewed. We expect to inspire research in the field of cartilage repair toward the future treatment of arthropathy.