Neuroprotective and Neurotherapeutic Effects of Tetrahedral Framework Nucleic Acids on Parkinson’s Disease in Vitro

Revitalizing Ancient Mitochondria with Nano-Strategies: Mitochondria-Remedying Nanodrugs Concentrate on Disease Control

Mitochondria, widely known as the energy factories of eukaryotic cells, have a myriad of vital functions across diverse cellular processes. Dysfunctions within mitochondria serve as catalysts for various diseases, prompting widespread cellular demise. Mounting research on remedying damaged mitochondria indicates that mitochondria constitute a valuable target for therapeutic intervention against diseases. But the less clinical practice and lower recovery rate imply the limitation of traditional drugs, which need a further breakthrough. Nanotechnology has approached favorable regiospecific biodistribution and high efficacy by capitalizing on excellent nanomaterials and targeting drug delivery. Mitochondria-remedying nanodrugs have achieved ideal therapeutic effects. This review elucidates the significance of mitochondria in various cells and organs, while also compiling mortality data for related diseases. Correspondingly, nanodrug-mediate therapeutic strategies and applicable mitochondria-remedying nanodrugs in disease are detailed, with a full understanding of the roles of mitochondria dysfunction and the advantages of nanodrugs. In addition, the future challenges and directions are widely discussed. In conclusion, this review provides comprehensive insights into the design and development of mitochondria-remedying nanodrugs, aiming to help scientists who desire to extend their research fields and engage in this interdisciplinary subject.

Framework nucleic acids as promising reactive oxygen species scavengers for anti-inflammatory therapy

Reactive oxygen species (ROS) are an array of derivatives of molecular oxygen that participate in multiple physiological processes under the control of redox homeostasis. However, under pathological conditions, the over-production of ROS often leads to oxidative stress and inflammatory reactions, indicating a potential therapeutic target. With the rapid development of nucleic acid nanotechnology, scientists have exploited various DNA nanostructures with remarkable biocompatibility, programmability, and structural stability. Among these novel organic nanomaterials, a group of skeleton-like framework nucleic acid (FNA) nanostructures attracts the most interest due to their outstanding self-assembly, cellular endocytosis, addressability, and functionality. Surprisingly, different FNAs manifest similarly satisfactory antioxidative and anti-inflammatory effects during their biomedical application process. First, they are intrinsically endowed with the ability to neutralize ROS due to their DNA nature. Therefore, they are extensively involved in the complicated inflammatory signaling network. Moreover, the outstanding editability of FNAs also allows for flexible modifications with nucleic acids, aptamers, peptides, antibodies, low-molecular-weight drugs, and so on, thus further strengthening the targeting and therapeutic ability. This review focuses on the ROS-scavenging potential of three representative FNAs, including tetrahedral framework nucleic acids (tFNAs), DNA origami, and DNA hydrogels, to summarize the recent advances in their anti-inflammatory therapy applications. Although FNAs exhibit great potential in treating inflammatory diseases as promising ROS scavengers, massive efforts still need to be made to overcome the emerging challenges in their clinical translation.

Tetrahedral framework nucleic acids for improving wound healing

Wounds are one of the most common health issues, and the cost of wound care and healing has continued to increase over the past decade. In recent years, there has been growing interest in developing innovative strategies to enhance the efficacy of wound healing. Tetrahedral framework nucleic acids (tFNAs) have emerged as a promising tool for wound healing applications due to their unique structural and functional properties. Therefore, it is of great significance to summarize the applications of tFNAs for wound healing. This review article provides a comprehensive overview of the potential of tFNAs as a novel therapeutic approach for wound healing. In this review, we discuss the possible mechanisms of tFNAs in wound healing and highlight the role of tFNAs in modulating key processes involved in wound healing, such as cell proliferation and migration, angiogenesis, and tissue regeneration. The targeted delivery and controlled release capabilities of tFNAs offer advantages in terms of localized and sustained delivery of therapeutic agents to the wound site. In addition, the latest research progress on tFNAs in wound healing is systematically introduced. We also discuss the biocompatibility and biosafety of tFNAs, along with their potential applications and future directions for research. Finally, the current challenges and prospects of tFNAs are briefly discussed to promote wider applications.

Neuroprotective effects of morroniside from Cornus officinalis sieb. Et zucc against Parkinson's disease via inhibiting oxidative stress and ferroptosis

Parkinson's disease (PD) is the second most common neurodegenera-tive disorder after Alzheimer disease accompanied by the death of dopaminergic neurons and brain nigrostriatal mitochondrial damage in the elderly population. The features of the disease include tremor, rigidity, postural instability, and motor retardation. The pathogenesis of Parkinson's disease is complex, and abnormal lipid metabolism resulting in ferroptosis due to the excessive accumulation of free radicals from oxidative stress in the substantia nigra of the brain was thought to be one of the factors causing the disease. Morroniside has been reported to have significant neuroprotective effects, although it has not been studied in PD. Therefore, this study focused on determining the neuroprotective effects of morroniside (25, 50, and 100 mg/kg) on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg)-induced mice models of PD and explored 1-methyl-4-phenylpyridinium MPP+-induced ferroptosis in PC12 cells. Morroniside restored impaired motor function in the PD mice models while reducing neuronal injury. The activation of nuclear factor erythroid 2-related factor 2/antioxidant response elements (Nrf2/ARE) by morroniside promoted antioxidation, the content of reducing agent glutathione (GSH) increased, and the level of the lipid metabolite malondialdehyde (MDA) decreased. Notably, morroniside inhibited ferroptosis in substantia nigra of the brain and PC12 cells, reduced iron levels, and upregulated the expression of the iron-regulated proteins glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), ferritin heavy chain 1 (FTH-1), and ferroportin (FPN). More importantly, morroniside repaired the mitochondrial damage, restored the mitochondrial respiratory chain, and inhibited the production of reactive oxygen species (ROS). These data indicated that morroniside could activate the Nrf2/ARE signaling pathway to increase the antioxidant capacity, thereby inhibiting abnormal lipid metabolism and protecting dopaminergic neurons from ferroptosis in PD.

Tetrahedral framework nucleic acids inhibit pathological neovascularization and vaso-obliteration in ischaemic retinopathy via PI3K/AKT/mTOR signalling pathway

This study aimed to explore the effect and the molecular mechanism of tetrahedral framework nucleic acids (tFNAs), a novel self-assembled nanomaterial with excellent biocompatibility and superior endocytosis ability, in inhibition of pathological retinal neovascularization (RNV) and more importantly, in amelioration of vaso-obliteration (VO) in ischaemic retinopathy. tFNAs were synthesized from four single-stranded DNAs (ssDNAs). Cell proliferation, wound healing and tube formation assays were performed to explore cellular angiogenic functions in vitro. The effects of tFNAs on reducing angiogenesis and inhibiting VO were explored by oxygen-induced retinopathy (OIR) model in vivo. In vitro, tFNAs were capable to enter endothelial cells (ECs), inhibit cell proliferation, tube formation and migration under hypoxic conditions. In vivo, tFNAs successfully reduce RNV and inhibit VO in OIR model via the PI3K/AKT/mTOR/S6K pathway, while vascular endothelial growth factor fusion protein, Aflibercept, could reduce RNV but not inhibit VO. This study provides a theoretical basis for the further understanding of RNV and suggests that tFNAs might be a novel promising candidate for the treatment of blind-causing RNV.

The PI3K-AKT pathway: A plausible therapeutic target in Parkinson's disease

Parkinson's disease is a common progressive and multifactorial neurodegenerative disease, characterized by the loss of midbrain dopaminergic neurons. Numerous pathological processes including, inflammation, oxidative stress, mitochondrial dysfunction, neurotransmitter imbalance, and apoptosis as well as genetic factors may lead to neuronal degeneration. With the emergence of aging population, the health problem and economic burden caused by PD also increase. Phosphatidylinositol 3-kinases-protein kinase B (PI3K-AKT) signaling pathway regulates signal transduction and biological processes such as cell proliferation, apoptosis and metabolism. According to reports, it regulates neurotoxicity and mediates the survival of neurons. Accumulating evidences indicate that some natural products can play a neuroprotective role by activating PI3K-AKT pathway, providing an effective resource for the discovery of potential therapeutic drugs. The current review provides an overview of the PI3K-AKT signaling pathway and review the relationship between this signaling pathway and PD.

Advances in regenerative medicine applications of tetrahedral framework nucleic acid-based nanomaterials: an expert consensus recommendation

With the emergence of DNA nanotechnology in the 1980s, self-assembled DNA nanostructures have attracted considerable attention worldwide due to their inherent biocompatibility, unsurpassed programmability, and versatile functions. Especially promising nanostructures are tetrahedral framework nucleic acids (tFNAs), first proposed by Turberfield with the use of a one-step annealing approach. Benefiting from their various merits, such as simple synthesis, high reproducibility, structural stability, cellular internalization, tissue permeability, and editable functionality, tFNAs have been widely applied in the biomedical field as three-dimensional DNA nanomaterials. Surprisingly, tFNAs exhibit positive effects on cellular biological behaviors and tissue regeneration, which may be used to treat inflammatory and degenerative diseases. According to their intended application and carrying capacity, tFNAs could carry functional nucleic acids or therapeutic molecules through extended sequences, sticky-end hybridization, intercalation, and encapsulation based on the Watson and Crick principle. Additionally, dynamic tFNAs also have potential applications in controlled and targeted therapies. This review summarized the latest progress in pure/modified/dynamic tFNAs and demonstrated their regenerative medicine applications. These applications include promoting the regeneration of the bone, cartilage, nerve, skin, vasculature, or muscle and treating diseases such as bone defects, neurological disorders, joint-related inflammatory diseases, periodontitis, and immune diseases.

Applications of tetrahedral DNA nanostructures in wound repair and tissue regeneration

Tetrahedral DNA nanostructures (TDNs) are molecules with a pyramidal structure formed by folding four single strands of DNA based on the principle of base pairing. Although DNA has polyanionic properties, the special spatial structure of TDNs allows them to penetrate the cell membrane without the aid of transfection agents in a caveolin-dependent manner and enables them to participate in the regulation of cellular processes without obvious toxic side effects. Because of their stable spatial structure, TDNs resist the limitations imposed by nuclease activity and innate immune responses to DNA. In addition, TDNs have good editability and biocompatibility, giving them great advantages for biomedical applications. Previous studies have found that TDNs have a variety of biological properties, including promoting cell migration, proliferation and differentiation, as well as having anti-inflammatory, antioxidant, anti-infective and immune regulation capabilities. Moreover, we confirmed that TDNs can promote the regeneration and repair of skin, blood vessels, muscles and bone tissues. Based on these findings, we believe that TDNs have broad prospects for application in wound repair and regeneration. This article reviews recent progress in TDN research and its applications.

Therapeutic Applications of Programmable DNA Nanostructures

Deoxyribonucleic acid (DNA) nanotechnology, a frontier in biomedical engineering, is an emerging field that has enabled the engineering of molecular-scale DNA materials with applications in biomedicine such as bioimaging, biodetection, and drug delivery over the past decades. The programmability of DNA nanostructures allows the precise engineering of DNA nanocarriers with controllable shapes, sizes, surface chemistries, and functions to deliver therapeutic and functional payloads to target cells with higher efficiency and enhanced specificity. Programmability and control over design also allow the creation of dynamic devices, such as DNA nanorobots, that can react to external stimuli and execute programmed tasks. This review focuses on the current findings and progress in the field, mainly on the employment of DNA nanostructures such as DNA origami nanorobots, DNA nanotubes, DNA tetrahedra, DNA boxes, and DNA nanoflowers in the biomedical field for therapeutic purposes. We will also discuss the fate of DNA nanostructures in living cells, the major obstacles to overcome, that is, the stability of DNA nanostructures in biomedical applications, and the opportunities for DNA nanostructure-based drug delivery in the future.

Tetrahedral Framework Nucleic Acids Can Alleviate Taurocholate-Induced Severe Acute Pancreatitis and Its Subsequent Multiorgan Injury in Mice

Severe acute pancreatitis (SAP) is an inflammatory disease of the pancreas accompanied by tissue injury and necrosis. It not only affects the pancreas but also triggers a systemic inflammatory response that leads to multiorgan failure or even death. Moreover, there is no effective treatment currently that can reverse the disease progression. In this study, tetrahedral framework nucleic acids (tFNAs) were utilized to treat SAP in mice for the first time and proved to be effective in suppressing inflammation and preventing pathological cell death. Serum levels of pancreatitis-related biomarkers witnessed significant changes after tFNAs treatment. Reduction in the expression of certain cytokines involved in local and systemic inflammatory response were observed, together with alteration in proteins related to cell death and apoptosis. Collectively, our results demonstrate that tFNAs could both alleviate SAP and its subsequent multiorgan injury in mice, thus offering a novel and effective option to deal with SAP in the future.

Nanomaterials for the delivery of bioactive factors to enhance angiogenesis of dermal substitutes during wound healing

Dermal substitutes provide a template for dermal regeneration and reconstruction. They constitutes an ideal clinical treatment for deep skin defects. However, rapid vascularization remains as a major hurdle to the development and application of dermal substitutes. Several bioactive factors play an important regulatory role in the process of angiogenesis and an understanding of the mechanism of achieving their effective delivery and sustained function is vital. Nanomaterials have great potential for tissue engineering. Effective delivery of bioactive factors (including growth factors, peptides and nucleic acids) by nanomaterials is of increasing research interest. This paper discusses the process of dermal substitute angiogenesis and the roles of related bioactive factors in this process. The application of nanomaterials for the delivery of bioactive factors to enhance angiogenesis and accelerate wound healing is also reviewed. We focus on new systems and approaches for delivering bioactive factors for enhancing angiogenesis in dermal substitutes.

A DNA Nanostructure-Based Neuroprotectant against Neuronal Apoptosis via Inhibiting Toll-like Receptor 2 Signaling Pathway in Acute Ischemic Stroke

Ischemic stroke is a main cause of cognitive neurological deficits and disability worldwide due to a plethora of neuronal apoptosis. Unfortunately, numerous neuroprotectants for neurons have failed because of biological toxicity, severe side effects, and poor efficacy. Tetrahedral framework nucleic acids (tFNAs) possess excellent biocompatibility and various biological functions. Here, we tested the efficacy of a tFNA for providing neuroprotection against neuronal apoptosis in ischemic stroke. The tFNA prevented apoptosis of neurons (SHSY-5Y cells) caused by oxygen-glucose deprivation/reoxygenation through interfering with ischemia cascades (excitotoxicity and oxidative stress) in vitro. It effectively ameliorated the microenvironment of the ischemic hemisphere by upregulating expression of erythropoietin and inhibiting inflammation, which reversed neuronal loss, alleviated cell apoptosis, significantly shrank the infarction volume from 33.9% to 2.7%, and attenuated neurological deficits in transient middle cerebral artery occlusion (tMCAo) rat models in vivo. In addition, blocking the TLR2-MyD88-NF-κB signaling pathway is a potential mechanism of the neuroprotection by tFNA in ischemic stroke. These findings indicate that tFNA is a safe pleiotropic nanoneuroprotectant and a promising therapeutic strategy for ischemic stroke.

Application of Programmable Tetrahedral Framework Nucleic Acid-Based Nanomaterials in Neurological Disorders: Progress and Prospects

Tetrahedral framework nucleic acid (tFNA), a special DNA nanodevice, is widely applied in diverse biomedical fields. Due to its high programmability, biocompatibility, tissue permeability as well as its capacity for cell proliferation and differentiation, tFNA presents a powerful tool that could overcome potential barriers in the treatment of neurological disorders. This review evaluates recent studies on the use and progress of tFNA-based nanomaterials in neurological disorders.

Functionalizing Framework Nucleic-Acid-Based Nanostructures for Biomedical Application

Strategies for functionalizing diverse tetrahedral framework nucleic acids (tFNAs) have been extensively explored since the first successful fabrication of tFNA by Turberfield. One-pot annealing of at least four DNA single strands is the most common method to prepare tFNA, as it optimizes the cost, yield, and speed of assembly. Herein, the focus is on four key merits of tFNAs and their potential for biomedical applications. The natural ability of tFNA to scavenge reactive oxygen species, along with remarkable enhancement in cellular endocytosis and tissue permeability based on its appropriate size and geometry, promotes cell-material interactions to direct or probe cell behavior, especially to treat inflammatory and degenerative diseases. Moreover, the structural programmability of tFNA enables the development of static tFNA-based nanomaterials via engineering of functional oligonucleotides or therapeutic molecules, and dynamic tFNAs via attachment of stimuli-responsive DNA apparatuses, leading to potential applications in targeted therapies, tissue regeneration, antitumor strategies, and antibacterial treatment. Although there are impressive performance and significant progress, the challenges and prospects of functionalizing tFNA-based nanostructures are still indicated in this review.

The biological applications of DNA nanomaterials: current challenges and future directions

DNA, a genetic material, has been employed in different scientific directions for various biological applications as driven by DNA nanotechnology in the past decades, including tissue regeneration, disease prevention, inflammation inhibition, bioimaging, biosensing, diagnosis, antitumor drug delivery, and therapeutics. With the rapid progress in DNA nanotechnology, multitudinous DNA nanomaterials have been designed with different shape and size based on the classic Watson-Crick base-pairing for molecular self-assembly. Some DNA materials could functionally change cell biological behaviors, such as cell migration, cell proliferation, cell differentiation, autophagy, and anti-inflammatory effects. Some single-stranded DNAs (ssDNAs) or RNAs with secondary structures via self-pairing, named aptamer, possess the ability of targeting, which are selected by systematic evolution of ligands by exponential enrichment (SELEX) and applied for tumor targeted diagnosis and treatment. Some DNA nanomaterials with three-dimensional (3D) nanostructures and stable structures are investigated as drug carrier systems to delivery multiple antitumor medicine or gene therapeutic agents. While the functional DNA nanostructures have promoted the development of the DNA nanotechnology with innovative designs and preparation strategies, and also proved with great potential in the biological and medical use, there is still a long way to go for the eventual application of DNA materials in real life. Here in this review, we conducted a comprehensive survey of the structural development history of various DNA nanomaterials, introduced the principles of different DNA nanomaterials, summarized their biological applications in different fields, and discussed the current challenges and further directions that could help to achieve their applications in the future.

Tetrahedral framework nucleic acids facilitate neurorestoration of facial nerves by activating the NGF/PI3K/AKT pathway

The facial nerve is a crucial nerve in the maxillofacial region and is vulnerable to damage. As a consequence of the complications during nerve restoration, existing remedies have certain limitations, thus the treatment of facial nerve injury is always a perplexing task for people. Regulation of Schwann cells is always the breakpoint of neurorestoration since Schwann cells count a great deal in injured nerve repair. In this study, we presented proof that tetrahedral framework nucleic acids (tFNAs), a kind of nucleic acid nanomaterial, were capable of regulating the neurorestorative pathway NGF/PI3 K/AKT, resulting in the activation of a series of cell behaviors related to injured nerve restoration such as proliferation and migration. In vivo experiments also proved that tFNAs enhanced the expressions of axon and myelin marker proteins, impelled histological recovery, promoted the efficient restoration of nerve conduction and muscle movement. Additionally, tFNAs possessed excellent biocompatibility and superior endocytosis ability. Thus, there is good potential for tFNAs to be applied in the therapy of facial nerve injury or even peripheral nerve injury.

Tetrahedral Framework Nucleic Acids Ameliorate Insulin Resistance in Type 2 Diabetes Mellitus via the PI3K/Akt Pathway

Insulin resistance (IR) is one of the essential conditions in the development of type 2 diabetes mellitus (T2DM). IR occurs in hepatic cells when the insulin receptor substrate-1 (IRS-1)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway is downregulated; thus, activating this pathway can significantly improve insulin sensitivity and ameliorate T2DM. Tetrahedral framework nucleic acids (tFNAs), a DNA nanomaterial, are synthesized from four single-stranded DNA molecules. tFNAs possess excellent biocompatibility and good water solubility and stability. tFNAs can promote cell proliferation, cell autophagy, wound healing, and nerve regeneration by activating the PI3K/Akt pathway. Herein, we explore the effects and underlying mechanisms of tFNAs on IR. The results displayed that tFNAs could increase glucose uptake and ameliorate IR by activating the IRS-1/PI3K/Akt pathway in glucosamine (GlcN)-stimulated HepG2 cells. By employing a PI3K inhibitor, we confirmed that tFNAs reduce IR through the PI3K/Akt pathway. Moreover, tFNAs can promote hepatic cell proliferation and inhibit GlcN-induced cell apoptosis. In a T2DM mouse model, tFNAs reduce blood glucose levels and ameliorate hepatic IR via the PI3K/Akt pathway. Taken together, tFNAs can improve hepatic IR and alleviate T2DM through the PI3K/Akt pathway, making contribution to the potential application of tFNAs in T2DM.

Preventive effect of tetrahedral framework nucleic acids on bisphosphonate-related osteonecrosis of the jaw

Zoledronic acid (ZA) is a bisphosphonate (BP) drug that has been widely used in clinical treatments as a potent bone resorption inhibitor. In recent years, an increasing number of cases of bisphosphonate-associated osteonecrosis of the jaw (BRONJ) have been reported. This is a severe maxillofacial complication characterized clinically by bone exposure, necrosis, pain, and halitosis. Its pathogenesis is still not clear, and there is no effective clinical treatment known. Therefore, prevention of BRONJ is especially important. To provide a new research direction for the treatment of BRONJ, this study used a new tetrahedral framework nucleic acid (TFNA), which can antagonize the inhibitory effect of ZA on the differentiation and maturation of osteoclasts (OCs). In vivo and in vitro experiments showed that TFNAs at a specific concentration exhibited no cytotoxicity and could reverse the inhibition of ZA on OC differentiation and maturation, effectively inhibiting the formation of BRONJ.

Tetrahedral Framework Nucleic Acids Induce Immune Tolerance and Prevent the Onset of Type 1 Diabetes

A failure in immune tolerance leads to autoimmune destruction of insulin-producing β-cells, leading to type 1 diabetes (T1D). Inhibiting autoreactive T cells and inducing regulatory T cells (Tregs) to re-establish immune tolerance are promising approaches to prevent the onset of T1D. Here, we investigated the ability of tetrahedral framework nucleic acids (tFNAs) to induce immune tolerance and prevent T1D in nonobese diabetic (NOD) mice. In prediabetic NOD mice, tFNAs treatment led to maintenance of normoglycemia and reduced incidence of diabetes. Moreover, the tFNAs (250 nM) treatment preserved the mass and function of β-cells, increased the frequency of Tregs, and suppressed autoreactive T cells, leading to immune tolerance. Collectively, our results demonstrate that tFNAs treatment aids glycemic control, provides β-cell protection, and prevents the onset of T1D in NOD mice by immunomodulation. These results highlight the potential of tFNAs for the prevention of autoimmune T1D.

Rationally Programming Nanomaterials with DNA for Biomedical Applications

DNA is not only a carrier of genetic information, but also a versatile structural tool for the engineering and self-assembling of nanostructures. In this regard, the DNA template has dramatically enhanced the scalability, programmability, and functionality of the self-assembled DNA nanostructures. These capabilities provide opportunities for a wide range of biomedical applications in biosensing, bioimaging, drug delivery, and disease therapy. In this review, the importance and advantages of DNA for programming and fabricating of DNA nanostructures are first highlighted. The recent progress in design and construction of DNA nanostructures are then summarized, including DNA conjugated nanoparticle systems, DNA-based clusters and extended organizations, and DNA origami-templated assemblies. An overview on biomedical applications of the self-assembled DNA nanostructures is provided. Finally, the conclusion and perspectives on the self-assembled DNA nanostructures are presented.

The protective effect of tetrahedral framework nucleic acids on periodontium under inflammatory conditions

Periodontitis is a common disease that causes periodontium defects and tooth loss. Controlling inflammation and tissue regeneration are two key strategies in the treatment of periodontitis. Tetrahedral framework nucleic acids can modulate multiple biological behaviors, and thus, their biological applications have been widely explored. In this study, we investigated the effect of tFNAs on periodontium under inflammatory conditions. Lipopolysaccharide and silk ligature were used to induce inflammation in vivo and in vitro. The results displayed that tFNAs decreased the release of pro-inflammatory cytokines and levels of cellular reactive oxygen species in periodontal ligament stem cells, which promoted osteogenic differentiation. Furthermore, animal experiments showed that tFNAs ameliorated the inflammation of the periodontium and protect periodontal tissue, especially reducing alveolar bone absorption by decreasing inflammatory infiltration and inhibiting osteoclast formation. These findings suggest that tFNAs can significantly improve the therapeutic effect of periodontitis and have the great potential significance in the field of periodontal tissue regeneration.

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tFNAs decreased the release of pro-inflammatory cytokines and promoted osteogenic differentiation.

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tFNAs ameliorated the inflammation of the periodontium and protect periodontal tissue.

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tFNAs can significantly improve the therapeutic effect of periodontitis.

Progress in Biomedical Applications of Tetrahedral Framework Nucleic Acid-Based Functional Systems

The past decades have witnessed the development of DNA nanotechnology and the emergence of various spatial DNA nanostructures, from two-dimensions to three-dimensions. The typical example is the tetrahedral framework nucleic acid (tFNA). In this review, we summarize the progress in fabrication, modification of tFNA-based functional systems and their potentials in biomedical applications. Through a one-step assembly process, tFNA is synthesized via four single stranded DNAs with three short sequences complementary to the other sequence of another single strand. Characterizations including polyacrylamide gel electrophoresis, atomic force microscopy, and dynamic light scattering measurement show tFNA as a pyramid-like nanostructure with the size of around 10 nm. Feathered with intrinsic biocompatibility and satisfactory cellular membrane permeability, the first generation of tFNA shows promising capacities in regulating cell biological behavior, promoting tissue regeneration, and immunomodulation. Along with excellent editability and relative biostability in complicated conditions, tFNA could be modified via hanging functional domains on the vertex or side arm and incorporating small-molecular-weight drugs to form the second generation, for reversing multidrug resistance in tumor cells or microorganisms, target therapy, anticancer and antibacterial treatments. The third generation of tFNA is currently tried via a multistep assembly process for stimuli-response and precise drug release. Although tFNAs show promising potentials in cargo delivery, massive efforts still need to be made to improve biostability, maximal load, and structural controllability.

Tetrahedral framework nucleic acids promote scarless healing of cutaneous wounds via the AKT-signaling pathway

While the skin is considered the first line of defense in the human body, there are some vulnerabilities that render it susceptible to certain threats, which is an issue that is recognized by both patients and doctors. Cutaneous wound healing is a series of complex processes that involve many types of cells, such as fibroblasts and keratinocytes. This study showed that tetrahedral framework nucleic acids (tFNAs), a type of self-assembled nucleic-acid material, have the ability to promote keratinocyte(HaCaT cell line) and fibroblast(HSF cell line) proliferation and migration in vitro. In addition, tFNAs increased the secretion of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in HSF cells and reduced the production of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) in HaCaT cells by activating the AKT-signaling pathway. During in vivo experiments, tFNA treatments accelerated the healing process in skin wounds and decreased the development of scars, compared with the control treatment that did not use tFNAs. This is the first study to demonstrate that nanophase materials with the biological features of nucleic acids accelerate the healing of cutaneous wounds and reduce scarring, which indicates the potential application of tFNAs in skin tissue regeneration.

Effects of the tetrahedral framework nucleic acids on the skeletal muscle regeneration in vitro and in vivo

The challenges associated with muscle degenerative diseases and volumetric muscle loss (VML) emphasizes the prospects of muscle tissue regeneration.