Designer DNA nanocages modulate anti-oxidative and anti-inflammatory responses in tumor associated macrophages

Cancer is a complex disease, with multiple treatment modalities, but no definitive cure. The tumor microenvironment contributes to the complexity of the disease by forming a niche of multiple cell types supporting each other to carry out various cellular functions. Tumor associated macrophages are one such kind of cells which support the tumor microenvironment via immunosuppression. DNA tetrahedron (TD), a widely explored DNA nanocage, has shown a lot of potential in therapeutics. However, the role of TD still remains quite unexplored in immunology. Here, we first establish the anti-oxidative and anti-inflammatory role of TD. We then proceed with using TD as a therapeutic agent in tumor associated macrophages by modulating the response of PD-L1. The findings of this work create a base for TD in biological applications such as cancer immunotherapy.

DNA origami-based composite nanosandwich for iteratively potentiated chemo-immunotherapy

Developing effective nanoplatforms for chemo-immunotherapy to achieve enhanced tumor suppression and systemic antitumor immunity has recently received extensive attention. Herein, we formulated a multifunctional DNA sandwich nanodevice, DSWAC/siPD-L1, based on triangular DNA origami, to implement enhanced cancer chemo-immunotherapy. Taking advantage of the tumor-targeting ability of the AS1411 aptamer, DSWAC/siPD-L1 efficiently delivered doxorubicin (DOX), CpG, and siPD-L1 into tumor cells. Moreover, the sandwich cavity spatially protects siPD-L1 from degradation, and the featured design of the DNA/RNA duplex linkers ensures effective intracellular release of siPD-L1. The pH-responsive release of cytotoxic DOX induces apoptosis and initial mild immunogenic cell death of tumor cells, presenting antigens to enhance the maturation of dendritic cells (DCs) with the assistance of the immune adjuvant CpG, thereby activating cytotoxic T lymphocytes to amplify antitumor immunity. Simultaneously, siPD-L1 downregulated the endogenous expression of PD-L1 to inhibit adaptive tumor immune escape. DSWAC/siPD-L1 initiated the iterative revolution of the cancer-immunity cycle, leading to the inhibition of primary and metastatic tumors, as demonstrated by DC maturation and T-cell infiltration in established subcutaneous primary tumor model and metastatic lung tumor model. Furthermore, the superior antitumor effect of DSWAC/siPD-L1 resulted in approximately 91 % inhibition of primary tumor growth and 93 % prevention of lung metastasis. Collectively, this study describes a siPD-L1-based sandwich DNA nanodevice functionalized with AS1411/CpG for enhanced cancer chemo-immunotherapy, inspiring the creation of more innovative drug nanocarriers and the exploitation of novel cancer therapies.

Folding an RCA Scaffold into an Intelligent Coiled Nanosnake for Precise/Synergistic RNAi-/Chemotherapy of Cancer

An RCA product is a promising scaffold for the construction of DNA nanostructures, but so far, there is no RCA scaffold-based dynamic reconfigurable nanorobot for biological applications. In this contribution, we develop an intracellular stimuli-responsive reconfigurable coiled DNA nanosnake (N-Snake) by using incomplete aptamer-functionalized (A) DNA tetrahedrons (T) to fold a long tandemly repetitive DNA strand synthesized by rolling circle amplification reaction (R) with the help of palindromic fragment (P). A DNA-assembled product, ARTP, including spiked aptamers, can retain the structural integrity even if exposed to fetal bovine serum (FBS) for 24 h and displays substantially enhanced target molecule-dependent cellular internalization efficiency. ARTP contains tetrahedral containers and linear containers, so that there are 500 doxorubicins (DOXs) and 12.5 siRNAs per ARTP. Moreover, ARTP can precisely transport anticancer drugs to cancerous sites and controllably release via the structural reconfiguration upon intracellular stimuli, almost 100% inhibiting tumor growth without detectable systemic toxicity owing to the synergistic RNAi-/Chemotherapy. Apparently, coiled N-snake, DOX/siPlk1-loaded ARTP, can specifically enter tumor cells, uncoil upon intracellular stimuli, and attack the cells from the inside, exerting precise cancer therapy.

Revolutionizing head and neck squamous cell carcinoma treatment with nanomedicine in the era of immunotherapy

Head and neck squamous cell carcinoma (HNSCC) is a prevalent malignant tumor globally. Despite advancements in treatment methods, the overall survival rate remains low due to limitations such as poor targeting and low bioavailability, which result in the limited efficacy of traditional drug therapies. Nanomedicine is considered to be a promising strategy in tumor therapy, offering the potential for maximal anti-tumor effects. Nanocarriers can overcome biological barriers, enhance drug delivery efficiency to targeted sites, and minimize damage to normal tissues. Currently, various nano-carriers for drug delivery have been developed to construct new nanomedicine. This review aims to provide an overview of the current status of HNSCC treatment and the necessity of nanomedicine in improving treatment outcomes. Moreover, it delves into the research progress of nanomedicine in HNSCC treatment, with a focus on enhancing radiation sensitivity, improving the efficacy of tumor immunotherapy, effectively delivering chemotherapy drugs, and utilizing small molecule inhibitors. Finally, this article discussed the challenges and prospects of applying nanomedicine in cancer treatment.

Mapping Endocytic Vesicular Acidification with a pH-Responsive DNA Nanomachine

Mapping the endocytic vesicular acidification process is of prior importance to better understand the health and pathological processes of cells. Herein, by integrating a pH-sensitive i-motif and a pair of fluorescence resonance energy transfer (FRET) into a tetrahedral DNA framework (TDF), we develop a pH-responsive DNA nanomachine, allowing for efficient sensing of pH from 7.0 to 5.5 via the pH-triggered spatial proximity modulation of FRET. The inheriting endo-lysosome-targeting ability of TDF enables spatiotemporal tracking of endocytic vesicle acidification during the endosomal maturation process. Analysis of pH-dependent FRET response at single fluorescent spot level reveals the significant difference of endocytic vesicular acidification between normal and cancer cells. The performance of pH-responsive DNA nanomachine underlines its potential for studies on vesicle acidification-related pathologies as a universal platform.

A splice-switch oligonucleotide loaded self-cleavable DNA nanogel

A self-cleavable DNA nanogel loaded with splice-switch oligonucleotide (SSO) has been developed. Under acidic conditions (pH 5.0), cleavage of the acid-labile chemical linker and generation of the i-motif structure led to the disintegration of the DNA nanogel and efficient release of SSO in its unaltered native state.

DNA Tetrahedra as Functional Nanostructures: From Basic Principles to Applications

Self-assembled supramolecular DNA tetrahedra composed of programmed sequence-engineered complementary base-paired strands represent elusive nanostructures having key contributions to the development and diverse applications of DNA nanotechnology. By appropriate engineering of the strands, DNA tetrahedra of tuneable sizes and chemical functionalities were designed. Programmed functionalities for diverse applications were integrated into tetrahedra structures including sequence-specific recognition strands (aptamers), catalytic DNAzymes, nanoparticles, proteins, or fluorophore. The article presents a comprehensive review addressing methods to assemble and characterize the DNA tetrahedra nanostructures, and diverse applications of DNA tetrahedra framework are discussed. Topics being addressed include the application of structurally functionalized DNA tetrahedra nanostructure for the assembly of diverse optical or electrochemical sensing platforms and functionalized intracellular sensing and imaging modules. In addition, the triggered reconfiguration of DNA tetrahedra nanostructures and dynamic networks and circuits emulating biological transformations are introduced. Moreover, the functionalization of DNA tetrahedra frameworks with nanoparticles provides building units for the assembly of optical devices and for the programmed crystallization of nanoparticle superlattices. Finally, diverse applications of DNA tetrahedra in the field of nanomedicine are addressed. These include the DNA tetrahedra-assisted permeation of nanocarriers into cells for imaging, controlled drug release, active chemodynamic/photodynamic treatment of target tissues, and regenerative medicine.

Nanosized DNA Hydrogel Functionalized with a DNAzyme Tetrahedron for Highly Efficient Gene Silencing

DNAzymes are DNA oligonucleotides that have catalytic activity without the assistance of protein enzymes. In particular, RNA-cleaving DNAzymes were considered as ideal candidates for gene therapy due to their unique characteristics. Nevertheless, efforts to use DNAzyme as a gene therapeutic agent are limited by issues such as their low physiological stability in serum and intracellular delivery efficiency. In this study, we developed a nanosized synthetic DNA hydrogel functionalized with a DNAzyme tetrahedron (TDz Dgel) to overcome these limitations. We observed remarkable improvement in the gene-silencing effect as well as intracellular uptake without the support of gene transfection reagents using TDz Dgel. The improved catalytic activity of the DNAzyme resulted from the combination of the cell-penetrating DNA tetrahedron structure and high stability of DNA hydrogel. We envision that this approach will become a convenient and efficient strategy for gene-silencing therapy using DNAzyme in the future.

Functionalizing tetrahedral framework nucleic acids-based nanostructures for tumor in situ imaging and treatment

Timely in situ imaging and effective treatment are efficient strategies in improving the therapeutic effect and survival rate of tumor patients. In recent years, there has been rapid progress in the development of DNA nanomaterials for tumor in situ imaging and treatment, due to their unsurpassed structural stability, excellent material editability, excellent biocompatibility and individual endocytic pathway. Tetrahedral framework nucleic acids (tFNAs), are a typical example of DNA nanostructures demonstrating superior stability, biocompatibility, cell-entry performance, and flexible drug-loading ability. tFNAs have been shown to be effective in achieving timely tumor in situ imaging and precise treatment. Therefore, the progress in the fabrication, characterization, modification and cellular internalization pathway of tFNAs-based functional systems and their potential in tumor in situ imaging and treatment applications were systematically reviewed in this article. In addition, challenges and future prospects of tFNAs in tumor in situ imaging and treatment as well as potential clinical applications were discussed.

Revolutionizing cancer therapy using tetrahedral DNA nanostructures as intelligent drug delivery systems

DNA nanostructures have surfaced as intriguing entities with vast potential in biomedicine, notably in the drug delivery area. Tetrahedral DNA nanostructures (TDNs) have received worldwide attention from among an array of different DNA nanostructures due to their extraordinary stability, great biocompatibility, and ease of functionalization. TDNs could be readily synthesized, making them attractive carriers for chemotherapeutic medicines, nucleic acid therapeutics, and imaging probes. Their varied uses encompass medication delivery, molecular diagnostics, biological imaging, and theranostics. This review extensively highlights the mechanisms of functional modification of TDNs and their applications in cancer therapy. Additionally, it discusses critical concerns and unanswered problems that require attention to increase the future application of TDNs in developing cancer treatment.

Supramolecular DNA nanogels through host-guest interaction for targeted drug delivery

DNA hydrogels have been demonstrated with the advantages of good stability, easy modification, and extraordinary biocompatibility, which enables their great application prospects in biosensing, tissue engineering, and biomedicine. Based on the host-guest recognition properties of cucurbit[8]uril (CB[8]), we proposed a general method for constructing functional supramolecular DNA nanogels. Guest molecules have been conjugated into the DNA building units, which could be further crosslinked with CB[8] to construct supramolecular DNA nanogels. At the same time, the aptamer has also been modified into the hydrogel network to achieve cell targeting. These supramolecular DNA nanogels have been demonstrated with a controllable size and multiple stimuli responses, in addition to the excellent biocompatibility, stability and good targeting drug transport ability. Such a host-guest based strategy will provide a molecular library as a "toolbox" for the functionalization of DNA nanogels.

DNA-based nanostructures for RNA delivery

RNA-based therapeutics have emerged as a promising approach for the treatment of various diseases, including cancer, genetic disorders, and infectious diseases. However, the delivery of RNA molecules into target cells has been a major challenge due to their susceptibility to degradation and inefficient cellular uptake. To overcome these hurdles, DNA-based nano technology offers an unprecedented opportunity as a potential delivery platform for RNA therapeutics. Due to its excellent characteristics such as programmability and biocompatibility, these DNA-based nanostructures, composed of DNA molecules assembled into precise and programmable structures, have garnered significant attention as ideal building materials for protecting and delivering RNA payloads to the desired cellular destinations. In this review, we highlight the current progress in the design and application of three DNA-based nanostructures: DNA origami, lipid-nanoparticle (LNP) technology related to frame guided assembly (FGA), and DNA hydrogel for the delivery of RNA molecules. Their biomedical applications are briefly discussed and the challenges and future perspectives in this field are also highlighted.

Oligonucleotide based nanogels for cancer therapeutics

Oligonucleotide-based nanogels, as nascent biomaterials, possess several unique functional, structural, and physicochemical features with excellent drug-loading capacity and high potential for cancer gene therapy. Ongoing studies utilizing oligonucleotide-based nanogels hold great promise, as these cutting-edge nanoplatforms can be elegantly developed with predesigned oligonucleotide sequences and complementary strands which are self-assembled or chemically crosslinked leading to the development of nanogels with predictable shape and tunable size with the desired functional properties. Current paper provides a summary of the properties, preparation methods, and applications of oligonucleotide-based nanogels in cancer therapy. The review is focused on both conventional and modified forms of oligonucleotide-based nanogels, including targeted nanogels, smart release nanogels (responsive to stimuli such as pH, temperature, and enzymes), as well as nanogels used for gene delivery. Their application in cancer immunotherapy and vaccination, photodynamic therapy, and diagnostic applications when combined with other nanoparticles is further discussed. Despite emerging designs in the development of oligonucleotide based nanogels, this field of study is still in its infancy, and clinical translation of these versatile nano-vehicles might face challenges. Hence, extensive research must be performed on in vivo behavior of such platforms determining their biodistribution, biological fate, and acute/subacute toxicity.

Recent Advances in Engineering Carriers for siRNA Delivery

RNA interference (RNAi) technology has been a promising treatment strategy for combating intractable diseases. However, the applications of RNAi in clinical are hampered by extracellular and intracellular barriers. To overcome these barriers, various siRNA delivery systems have been developed in the past two decades. The first approved RNAi therapeutic, Patisiran (ONPATTRO) using lipids as the carrier, for the treatment of amyloidosis is one of the most important milestones. This has greatly encouraged researchers to work on creating new functional siRNA carriers. In this review, the recent advances in siRNA carriers consisting of lipids, polymers, and polymer-modified inorganic particles for cancer therapy are summarized. Representative examples are presented to show the structural design of the carriers in order to overcome the delivery hurdles associated with RNAi therapies. Finally, the existing challenges and future perspective for developing RNAi as a clinical modality will be discussed and proposed. It is believed that the addressed contributions in this review will promote the development of siRNA delivery systems for future clinical applications.

Persistent Targeting DNA Nanocarrier Made of 3D Structural Unit Assembled from Only One Basic Multi-Palindromic Oligonucleotide for Precise Gene Cancer Therapy

Construction of a simple, reconfigurable, and stimuli-responsive DNA nanocarrier remains a technical challenge. In this contribution, by designing three palindromic fragments, a simplest four-sticky end-contained 3D structural unit (PS-unit) made of two same DNA components is proposed. Via regulating the rotation angle of central longitudinal axis of PS-unit, the oriented assembly of one-component spherical architecture is accomplished with high efficiency. Introduction of an aptamer and sticky tail warehouse into one component creates a size-change-reversible targeted siRNA delivery nanovehicle. Volume swelling of 20 nm allows one carrier to load 1987 siPLK1s. Once entering cancer cells and responding to glutathione (GSH) stimuli, siPLK1s are almost 100% released and original size of nanovehicle is restored, inhibiting the expression of PLK1 protein and substantially suppressing tumor growth (superior to commercial transfection agents) in tumor-bearing mice without systemic toxicity.

Nanogels: Smart tools to enlarge the therapeutic window of gene therapy

Gene therapy can potentially treat a great number of diseases, from cancer to rare genetic disorders. Very recently, the development and emergency approval of nucleic acid-based COVID-19 vaccines confirmed its strength and versatility. However, gene therapy encounters limitations due to the lack of suitable carriers to vectorize therapeutic genetic material inside target cells. Nanogels are highly hydrated nano-size crosslinked polymeric networks that have been used in many biomedical applications, from drug delivery to tissue engineering and diagnostics. Due to their easy production, tunability, and swelling properties they have called the attention as promising vectors for gene delivery. In this review, nanogels are discussed as vectors for nucleic acid delivery aiming to enlarge gene therapy's therapeutic window. Recent works highlighting the optimization of inherent transfection efficiency and biocompatibility are reviewed here. The importance of the monomer choice, along with the internal structure, surface decoration, and responsive features are outlined for the different transfection modalities. The possible sources of toxicological endpoints in nanogels are analyzed, and the strategies to limit them are compared. Finally, perspectives are discussed to identify the remining challenges for the nanogels before their translation to the market as transfection agents.

A Self-Immolative DNA Nanogel Vaccine toward Cancer Immunotherapy

The development of precisely engineered vehicles for intracellular delivery and the controlled release of payloads remains a challenge. DNA-based nanomaterials offer a promising solution based on the A-T-G-C alphabet-dictated predictable assembly and high programmability. Herein, we present a self-immolative DNA nanogel vaccine, which can be tracelessly released in the intracellular compartments and activate the immune response. Three building blocks with cytosine-rich overhang domains are designed to self-assemble into a DNA nanogel framework with a controlled size. Two oligo agonists and one antigen peptide are conjugated to the building blocks via an acid-labile chemical linker. Upon internalization into acidic endosomes, the formation of i-motif configurations leads to dissociation of the DNA nanogel vaccine. The acid-labile chemical linker is cleaved, releasing the agonists and antigen in their traceless original form to activate antigen-presenting cells and an immune response. This study presents a novel strategy for constructing delivery platforms for intracellularly stimuli-triggered traceless release of therapeutics.

A pH-Responsive DNA Tetrahedron/Methotrexate Drug Delivery System Used for Rheumatoid Arthritis Treatment

Rheumatoid arthritis (RA) is a chronic autoimmune disorder that leads to progressive and aggressive joint inflammation. The disease process is characterized by the activation of macrophages, which then release tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), accelerating tissue damage. Tackling tissue damage is a crucial target in the treatment of RA. In this study, a macrophage-targeted and pH-response DNA tetrahedron/methotrexate drug delivery system was constructed by loading methotrexate (MTX) onto a DNA duplex. MTX was used as a drug model, and a pH-response DNA tetrahedron (TET) was used as the drug carrier, which was modified with hyaluronic acid (HA) to target macrophages. The aim of this study was to evaluate the potential of TET as an effective drug carrier for the treatment of RA. On this basis, we successfully prepared TETs loaded with MTX, and in vitro assays showed that the MTX-TET treatment could successfully target macrophages and induce macrophages to polarize to M1 phenotype. At the same time, we also injected MTX-TET intravenously into collagen-induced arthritis (CIA) model mice, and the redness and swelling of the paws of mice were significantly alleviated, proving that the MTX-TET could successfully target inflamed joints and release MTX to treat joint swelling. In addition, the histochemical results showed that the MTX-TET could reduce synovitis and joint swelling in CIA mice, reduce the level of inflammatory factors in vivo, and improve the disease status while maintaining a good biosafety profile. This study showed that the MTX-TET treatment has beneficial therapeutic effects on RA, providing a new strategy for the clinical treatment of RA.

Advanced applications of DNA nanostructures dominated by DNA origami in antitumor drug delivery

DNA origami is a cutting-edge DNA self-assembly technique that neatly folds DNA strands and creates specific structures based on the complementary base pairing principle. These innovative DNA origami nanostructures provide numerous benefits, including lower biotoxicity, increased stability, and superior adaptability, making them an excellent choice for transporting anti-tumor agents. Furthermore, they can considerably reduce side effects and improve therapy success by offering precise, targeted, and multifunctional drug delivery system. This comprehensive review looks into the principles and design strategies of DNA origami, providing valuable insights into this technology's latest research achievements and development trends in the field of anti-tumor drug delivery. Additionally, we review the key function and major benefits of DNA origami in cancer treatment, some of these approaches also involve aspects related to DNA tetrahedra, aiming to provide novel ideas and effective solutions to address drug delivery challenges in cancer therapy.

Cation-free siRNA-cored nanocapsules for tumor-targeted RNAi therapy

Cation-associated cytotoxicity limits the systemic administration of RNA delivery in vivo, demanding the development of non-cationic nanosystems. In this study, cation-free polymer-siRNA nanocapsules with disulfide-crosslinked interlayer, namely T-SS(-), were prepared via the following steps: 1) complexation of siRNA with a cationic block polymer cRGD-poly(ethylene glycol)-b-poly[(2-aminoethanethiol)aspartamide]-b-poly{N'-[N-(2-aminoethyl)-2-ethylimino-1-aminomethyl]aspartamide}, abbreviated as cRGD-PEG-PAsp(MEA)-PAsp(C=N-DETA), 2) interlayer crosslinking via disulfide bond in pH 7.4 solution, and 3) removal of cationic DETA pendant at pH 5.0 via breakage of imide bond. The cationic-free nanocapsules with siRNA cores not only showed great performance (such as efficient siRNA encapsulation, high stability in serum, cancer cell targeting via cRGD modification, and GSH-triggered siRNA release), but also achieved tumor-targeted gene silencing in vivo. Moreover, the nanocapsules loaded with siRNA against polo-like kinase 1 (siRNA-PLK1) significantly inhibited tumor growth without showing cation-associated toxicity side effects and remarkably improved the survival rate of PC-3 tumor-bearing mice. The cation-free nanocapsules could potentially serve as a safe and effective platform for siRNA delivery. STATEMENT OF SIGNIFICANCE: Cation-associated toxicity limits the clinical translation of cationic carriers for siRNA delivery. Recently, several non-cationic carriers, such as siRNA micelles, DNA-based nanogels, and bottlebrush-architectured poly(ethylene glycol), have been developed to deliver siRNA. However, in these designs, siRNA as a hydrophilic macromolecule was attached to the nanoparticle surface instead of being encapsulated. Thus, it was easily degraded by serum nuclease and often induced immunogenicity. Herein, we demonstrate a new type of cation-free siRNA-cored polymeric nanocapsules. The developed nanocapsules not only showed capacities including efficient siRNA encapsulation, high stability in serum, and cancer cell targeting via cRGD modification, but also achieved an efficient tumor-targeted gene silencing in vivo. Importantly, unlike cationic carriers, the nanocapsules exhibited no cation-associated side effects.

Cucurbit[7]uril-Based Supramolecular DNA Nanogel for Targeted Codelivery of Chemo/Photodynamic Drugs

Nanodrug delivery systems for the delivery of combination therapeutics have shown their exceptionally potential clinical application by facilitating better synergistic anticancer effects. Herein, we developed a universal strategy to fabricate supramolecular DNA nanogels from DNA tetrahedron skeleton and cucurbit[7]uril-based host-guest interaction for codelivery the chemo and photodynamic therapy drugs. The constructed supramolecular DNA nanogels showed the size tunability, host-guest competition and DNA enzyme responsibility. The cell uptake and MTT experiments demonstrated that the nanogel has excellent biocompatibility and specificity, and achieved the enrichment and slow release of drug in cells. Finally, the combined chemo/photodynamic therapy was realized by coloading doxorubicin hydrochloride and methylene blue. It was proven to be a better stragety to promote apoptosis of cancer cells compared to single chemotherapy or photodynamic therapy. These results suggest that our proposed supramolecular nanogels have provided an effective nanoplatform for drug delivery in the combinational therapy for cancer.

A Thermal and Enzymatic Dual-Stimuli Responsive DNA-Based Nanomachine for Controlled mRNA Delivery

The extreme instability of mRNA makes the practical application of mRNA-based vaccines heavily rely on efficient delivery system and cold chain transportation. Herein, a DNA-based nanomachine, which achieves programmed capture, long-term storage without cryopreservation, and efficient delivery of mRNA in cells, is developed. The polythymidine acid (Poly-T) functionalized poly(N-isopropylacrylamide) (DNA-PNIPAM) is synthesized and assembled as the central compartment of the nanomachine. The DNA-PNIPAM nano-assembly exhibits reversible thermal-responsive dynamic property: when lower than the low critical solution temperature (LCST, ≈32 °C) of PNIPAM, the DNA-PNIPAM transforms into extension state to expose the poly-T, facilitating the hybridization with polyadenylic acid (Poly-A) tail of mRNA; when higher than LCST, DNA-PNIPAM re-assembles and achieves an efficient encapsulation of mRNA. It is remarkable that the DNA-PNIPAM nano-assembly realizes long-term storage of mRNA (≈7 days) at 37 °C. Biodegradable 2-hydroxypropyltrimethyl ammonium chloride chitosan is assembled on the outside of DNA-PNIPAM to facilitate the endocytosis of mRNA, RNase-H mediating mRNA release occurs in cytoplasm, and efficient mRNA translation is achieved. This work provides a new disign principle of nanosystem for mRNA delivery.

Biomedicine Innovations and Its Nanohydrogel Classifications

As one of the most cutting-edge and promising polymer crosslinked network nanoparticle systems. Polymer nano-sized hydrogels (nanogels) have been a hot topic in the biomedical field over the last few decades. Due to their unique characteristics, which include their relatively high drug encapsulation efficiency, ease of preparation, high tunability, low toxicity, high stability in serum and responsive behavior to a range of stimuli to facilitate drug release. Nanogels are thought to be the next generation of drug delivery systems that can completely change the way that drug delivery systems have an impact on patients' lives. Nanogels have demonstrated significant potential in a variety of fields, including chemotherapy, diagnosis, organ targeting, and delivery of bioactive molecules of different dimensions. However, the lack of substantial clinical data from nanogels becomes one of the major barriers to translating the nanogel concept into a practical therapeutic application for many disease conditions. In addition, nanogel safety profiles have been the major concern that hinders it advancement to the clinical trial phase. This review aims to emphasize the unique properties of nanogels as delivery systems for a variety of bioactive molecules over other nano-delivery systems. Also, this review attempts to give insight into the recent progress in nanogels as a carrier in the field of nanomedicine to overcome complex biological barriers. Relevant scientific data and clinical rationale for the development and the potential use of nanogel as a carrier for targeted therapeutic interventions are discussed. Finally, the concluding points of this review highlight the importance of understanding the long-term toxicity profile of nanogel within the biological system to fully understand their biocompatibility.

A Tetrahedral Framework DNA-Based Bioswitchable miRNA Inhibitor Delivery System: Application to Skin Anti-Aging

MicroRNA (miR)-based therapy shows strong potential; however, structural limitations pose a challenge in fully exploiting its biomedical functionality. Tetrahedral framework DNA (tFNA) has proven to be an ideal vehicle for miR therapy. Inspired by the ancient Chinese myth "Sun and Immortal Birds," a novel bioswitchable miR inhibitor delivery system (BiRDS) is designed with three miR inhibitors (the three immortal birds) and a nucleic acid core (the central sun). The BiRDS fuses miR inhibitors within the framework, maximizing their loading capacity, while allowing the system to retain the characteristics of small-sized tFNA and avoiding uncertainty associated with RNA exposure in traditional loading protocols. The RNase H-responsive sequence at the tail of each "immortal bird" enables the BiRDS to transform from a 3D to a 2D structure upon entering cells, promoting the delivery of miR inhibitors. To confirm the application potential, the BiRDS is used to deliver the miR-31 inhibitor, with antiaging effects on hair follicle stem cells, into a skin aging model. Superior skin penetration ability and RNA delivery are observed with significant anti-aging effects. These findings demonstrate the capability and editability of the BiRDS to improve the stability and delivery efficacy of miRs for future innovations.

Spatio-Temporal Controlled Gene-Chemo Drug Delivery in a DNA Nanocomplex to Overcome Multidrug Resistance of Cancer Cells

Multidrug resistance (MDR) in cancer cells is a substantial limitation to the success of chemotherapy. The spatio-temporal controlled gene-chemo therapeutics strategy is expected to surmount the limitation of MDR. We herein develop a DNA nanocomplex to achieve intrinsic stimuli-responsive spatio-temporal controlled gene-chemo drug delivery, overcoming MDR of cancer cells. The drug delivery system consisted of a restriction endonuclease (HhaI)-degradable DNA hydrogel layer, an acid-responsive HhaI nanocapsule (HhaI-GDA), and a glutathione (GSH)-sensitive dendritic mesoporous organosilica nanoparticle (DMON). The DNA hydrogel layer consisted of a DNA network formed through interfacial assembly from ultralong single-stranded DNA (ssDNA), which contained multiple tandem repeated antisense oligonucleotides (ASOs). DMON had dendritic mesopores for enhanced loading of anti-tumor drug doxorubicin (DOX). Upon cellular uptake of the DNA nanocomplex, the GDA shell was degraded at a lysosomal microenvironment, and the activity of HhaI was activated, leading to accurate cleavage ultralong ssDNA to release ASO as gene drugs, which down-regulated the expression of MDR-related P glycoprotein. Spatio-temporal sequentially, DMONs containing disulfide bonds responded to intracellular GSH to release DOX for enhanced chemotherapy.

Molecular Visualization of Early-Stage Acute Kidney Injury with a DNA Framework Nanodevice

DNA nanomachines with artificial intelligence have attracted great interest, which may open a new era of precision medicine. However, their in vivo behavior, including early diagnosis and therapeutic effect are limited by their targeting efficiency. Here, a tetrahedral DNA framework (TDF)-based nanodevice for in vivo near-infrared (NIR) diagnosis of early-stage AKI is developed. This nanodevice comprises three functional modules: a size-tunable TDF nanostructure as kidney-targeting vehicle, a binding module for the biomarker kidney injury molecule-1 (Kim-1), and a NIR signaling module. The cooperation of these modules allows the nanodevice to be selectively accumulated in injured kidney tissues with high Kim-1 level, generating strong NIR fluorescence; whereas the nanodevice with the proper size can be rapidly cleared in healthy kidneys to minimize the background. By using this nanodevice, the early diagnosis of AKI onset is demonstrated at least 6 h ahead of Kim-1 urinalysis, or 12 h ahead of blood detection. It is envisioned that this TDF-based nanodevice may have implications for the early diagnosis of AKI and other kidney diseases.

Prospects and challenges of dynamic DNA nanostructures in biomedical applications

The physicochemical nature of DNA allows the assembly of highly predictable structures via several fabrication strategies, which have been applied to make breakthroughs in various fields. Moreover, DNA nanostructures are regarded as materials with excellent editability and biocompatibility for biomedical applications. The ongoing maintenance and release of new DNA structure design tools ease the work and make large and arbitrary DNA structures feasible for different applications. However, the nature of DNA nanostructures endows them with several stimulus-responsive mechanisms capable of responding to biomolecules, such as nucleic acids and proteins, as well as biophysical environmental parameters, such as temperature and pH. Via these mechanisms, stimulus-responsive dynamic DNA nanostructures have been applied in several biomedical settings, including basic research, active drug delivery, biosensor development, and tissue engineering. These applications have shown the versatility of dynamic DNA nanostructures, with unignorable merits that exceed those of their traditional counterparts, such as polymers and metal particles. However, there are stability, yield, exogenous DNA, and ethical considerations regarding their clinical translation. In this review, we first introduce the recent efforts and discoveries in DNA nanotechnology, highlighting the uses of dynamic DNA nanostructures in biomedical applications. Then, several dynamic DNA nanostructures are presented, and their typical biomedical applications, including their use as DNA aptamers, ion concentration/pH-sensitive DNA molecules, DNA nanostructures capable of strand displacement reactions, and protein-based dynamic DNA nanostructures, are discussed. Finally, the challenges regarding the biomedical applications of dynamic DNA nanostructures are discussed.

Copackaging photosensitizer and PD-L1 siRNA in a nucleic acid nanogel for synergistic cancer photoimmunotherapy

Packaging multiple drugs into a nanocarrier with rational design to achieve synergistic cancer therapy remains a challenge due to the intrinsically varied pharmacodynamics of therapeutic agents. Especially difficult is combining small-molecule drugs and macromolecular biologics. Here, we successfully graft pheophorbide A (PPA) photosensitizers on DNA backbone at predesigned phosphorothioate modification sites. The synthesized four PPA-grafted DNAs are assembled into a tetrahedron framework, which further associates with a programmed death ligand-1 (PD-L1) small interfering RNA (siRNA) linker through supramolecular self-assembly to form an siRNA and PPA copackaged nanogel. With dual therapeutic agents inside, the nanogel can photodynamically kill tumor cells and induce remarkable immunogenic cell death. Also, it simultaneously silences the PD-L1 expression of the tumor cells, which substantially promotes the antitumor immune response and leads to an enhanced antitumor efficacy in a synergistic fashion.

DNA origami nanocalipers for pH sensing at the nanoscale

A DNA origami nanocaliper is employed as a shape-resolved nanomechanical device, with pH-responsive triplex DNA integrated into the two arms. The shape transition of the nanocaliper results in a subtle difference depending on the local pH that is visible via TEM imaging, demonstrating the potential of these nanocalipers to act as a universal platform for pH sensing at the nanoscale.

Self-assembled tetrahedral framework nucleic acid mediates tumor-associated macrophage reprogramming and restores antitumor immunity

There is increasing interest in depleting or repolarizing tumor-associated macrophages (TAMs) to generate a proinflammatory effect. However, TAMs usually display an immunosuppressive M2-like phenotype in the tumor microenvironment. Apparently, developing a macrophage-targeting delivery system with immunomodulatory agents is urgent. In this study, an efficient siRNA and CpG ODNs delivery system (CpG-siRNA-tFNA) was prepared with nucleic acid stepwise self-assembled. The tFNA composed of CpG ODNs and siRNA showed a higher stability and an enhanced cellular uptake efficiency. Moreover, the CpG-siRNA-tFNA effectively reprogrammed TAMs toward M1 phenotype polarization with increased proinflammatory cytokine secretion and NF-κB signal pathway activation, which triggers dramatic antitumor immune responses. Additionally, the CpG-siRNA-tFNA exhibited superior antitumor efficacy in a breast cancer xenograft mouse model without obvious systemic side effects. Taken together, CpG-siRNA-tFNA displayed greatly antitumor effect by facilitating TAM polarization toward M1 phenotypes in favor of immunotherapy. Hence, we have developed an efficient therapeutic strategy with immunomodulatory agents for clinical 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.

Smart Drug Delivery Systems Based on DNA Nanotechnology

The development of DNA nanotechnology has attracted tremendous attention in biotechnological and biomedical fields involving biosensing, bioimaging and disease therapy. In particular, precise control over size and shape, easy modification, excellent programmability and inherent homology make the sophisticated DNA nanostructures vital for constructing intelligent drug carriers. Recent advances in the design of multifunctional DNA-based drug delivery systems (DDSs) have demonstrated the effectiveness and advantages of DNA nanostructures, showing the unique benefits and great potential in enhancing the delivery of pharmaceutical compounds and reducing systemic toxicity. This Review aims to overview the latest researches on DNA nanotechnology-enabled nanomedicine and give a perspective on their future opportunities.

RNA Drug Delivery Using Biogenic Nanovehicles for Cancer Therapy

RNA-based therapies have been promising method for treating all kinds of diseases, and four siRNA-based drugs and two mRNA-based drugs have been approved and are on the market now. However, none of them is applied for cancer treatment. This is not only because of the complexity of the tumor microenvironment, but also due to the intrinsic obstacles of RNAs. Until now, all kinds of strategies have been developed to improve the performance of RNAs for cancer therapy, especially the nanoparticle-based ones using biogenic materials. They are much more compatible with less toxicity compared to the ones using synthetic polymers, and the most widely studied biogenic materials are oligonucleotides, exosomes, and cell membranes. Particular characteristics make them show different capacities in internalization and endosomal escape as well as specific targeting. In this paper, we systematically summarize the RNA-based nano-delivery systems using biogenic materials for cancer therapy, and we believe this review will provide a valuable reference for researchers involved in the field of biogenic delivery and RNA-based therapies for cancer treatment.

Non-viral vectors for RNA delivery

RNA-based therapy is a promising and potential strategy for disease treatment by introducing exogenous nucleic acids such as messenger RNA (mRNA), small interfering RNA (siRNA), microRNA (miRNA) or antisense oligonucleotides (ASO) to modulate gene expression in specific cells. It is exciting that mRNA encoding the spike protein of COVID-19 (coronavirus disease 2019) delivered by lipid nanoparticles (LNPs) exhibits the efficient protection of lungs infection against the virus. In this review, we introduce the biological barriers to RNA delivery in vivo and discuss recent advances in non-viral delivery systems, such as lipid-based nanoparticles, polymeric nanoparticles, N-acetylgalactosamine (GalNAc)-siRNA conjugate, and biomimetic nanovectors, which can protect RNAs against degradation by ribonucleases, accumulate in specific tissue, facilitate cell internalization, and allow for the controlled release of the encapsulated therapeutics.

RNA interference (RNAi)-based plasmonic nanomaterials for cancer diagnosis and therapy

RNA interference (RNAi) is being extensively investigated as a potential therapeutic strategy for cancer treatment. However, RNAi-based therapeutics have not yet been used to treat cancer because of their instability and the difficulty of microRNA (miRNA) delivery. Plasmonic nanoparticle-based RNAi nanotherapeutics have been developed for accurate and sensitive diagnosis and a strong therapeutic effect on cancers by leveraging their ease-of-use and specific properties such as photothermal conversion. In this review, recent strategies and advances in plasmonic nanoparticle-based miRNA delivery are briefly presented to facilitate the detection and treatment of several cancers. The challenges and potential opportunities afforded by the RNAi-based theragnosis field are discussed. We expect that the RNAi-integrated plasmonic nanotherapeutics discussed in this review can provide insights for the early diagnosis and effective treatment of cancer.

Designer DNA Hydrogels Stimulate 3D Cell Invasion by Enhanced Receptor Expression and Membrane Endocytosis

DNA has emerged as one of the smartest biopolymers to bridge the gap between chemical science and biology to design scaffolds like hydrogels by physical entanglement or chemical bonding with remarkable properties. We present here a completely new application of DNA-based hydrogels in terms of their capacity to stimulate membrane endocytosis, leading to enhanced cell spreading and invasion for cells in ex vivo 3D spheroids models. Multiscale simulation studies along with DLS data showed that the hydrogel formation was enhanced at lower temperature and it converts to liquid with increase in temperature. DNA hydrogels induced cell spreading as observed by the increase in cellular area by almost two-fold followed by an increase in the receptor expression, the endocytosis, and the 3D invasion potential of migrating cells. Our first results lay the foundation for upcoming diverse applications of hydrogels to probe and program various cellular and physiological processes that can have lasting applications in stem cell programming and regenerative therapeutics.

Bioswitchable Delivery of microRNA by Framework Nucleic Acids: Application to Bone Regeneration

MicroRNAs (miRs) play an important role in regulating gene expression. Limited by their instabilities, miR therapeutics require delivery vehicles. Tetrahedral framework nucleic acids (tFNAs) are potentially applicable to drug delivery because they prominently penetrate tissue and are taken up by cells. However, tFNA-based miR delivery strategies have failed to separate the miRs after they enter cells, affecting miR efficiency. In this study, an RNase H-responsive sequence is applied to connect a sticky-end tFNA (stFNA) and miR-2861, which is a model miR, to target the expression of histone deacetylase 5 (HDAC5) in bone marrow mesenchymal stem cells. The resultant bioswitchable nanocomposite (stFNA-miR) enables efficient miR-2861 unloading and deployment after intracellular delivery, thereby inhibiting the expression of HDAC5 and promoting osteogenic differentiation. stFNA-miR also facilitated ideal bone repair via topical injection. In conclusion, a versatile miR delivery strategy is offered for various biomedical applications that necessitate modulation of gene expression.

Cyclic Peptide-Gadolinium Nanocomplexes as siRNA Delivery Tools

We have recently reported that a cyclic peptide containing five tryptophan, five arginine, and one cysteine amino acids [(WR)5C], was able to produce peptide-capped gadolinium nanoparticles, [(WR)5C]-GdNPs, in the range of 240 to 260 nm upon mixing with an aqueous solution of GdCl3. Herein, we report [(WR)5C]-GdNPs as an efficient siRNA delivery system. The peptide-based gadolinium nanoparticles (50 µM) did not exhibit significant cytotoxicity (~93% cell viability at 50 µM) in human leukemia T lymphoblast cells (CCRF-CEM) and triple-negative breast cancer cells (MDA-MB-231) after 48 h. Fluorescence-activated cell sorting (FACS) analysis indicated that the cellular uptakes of Alexa-488-labeled siRNA were found to be enhanced by more than 10 folds in the presence of [(WR)5C]-GdNPs compared with siRNA alone in CCRF-CEM and MDA-MB-231 cells after 6 h of incubation at 37 °C. The gene silencing efficacy of the nanoparticles was determined via the western blot technique using an over-expressed gene, STAT-3 protein, in MDA-MB-231 cells. The results showed ~62% reduction of STAT-3 was observed in MDA-MB-231 with [(WR)5C]-GdNPs at N/P 40. The integrity of the cellular membrane of CCRF-CEM cells was found to be intact when incubated with [(WR)5C]-Gd nanoparticles (50 µM) for 2 h. Confocal microscopy reveals higher internalization of siRNA in MDA-MB-231 cells using [(WR)5C]-GdNPs at N/P 40. These results provided insight about the use of the [(WR)5C]-GdNPs complex as a potent intracellular siRNA transporter that could be a nontoxic choice to be used as a transfection agent for nucleic-acid-based therapeutics.

An Aptamer-Modified DNA Tetrahedron-Based Nanogel for Combined Chemo/Gene Therapy of Multidrug-Resistant Tumors

DNA-based nanogels have attracted much attention in the biomedical research field. Herein, we report a universal strategy for the fabrication of an aptamer-modified DNA tetrahedron (TET)-based nanogel for combined chemo/gene therapy of multidrug-resistant tumors. In our design, terminal extended antisense oligonucleotides (ASOs) are employed as the linker to co-assemble with two kinds of three-vertex extended TETs for the efficient construction of the DNA-based nanogel. With the incorporation of an active cell-targeting group (aptamer in one vertex of TET) and a controlled-release element (disulfide bridges in the terminals of ASOs), the functional DNA-based nanogel can achieve targeted cellular internalization and stimuli-responsive release of embedded ASOs. After loading with the chemodrug (doxorubicin (DOX), an intercalator of double-stranded DNA), the multifunctional DOX/Nanogel elicits efficient chemo/gene therapy of human MCF-7 breast tumor cells with DOX resistance (MCF-7R). This aptamer-modified DNA tetrahedron-based nanogel provides another strategy for intelligent drug delivery and combined tumor therapy.

Multimodules integrated functional DNA nanomaterials for intelligent drug delivery

Deoxyribonucleic acid (DNA) has been an emerging building block to construct functional biomaterials. Due to their programmable sequences and rich responsiveness, DNA has attracted rising attention in the construction of intelligent nanomaterials with predicable nanostructure and adjustable functions, which has shown great potential in drug delivery. On the one hand, the DNA sequences with molecule recognition, responsiveness, and therapeutic efficacy can be easily integrated to the framework of DNA nanomaterials by sequence designing; on the other hand, the rich chemical groups on DNA molecules provide binding points for other functional units. In this review, we divided the functionalization modules in the construction of DNA nanomaterials into three types, including targeting modules, responsive modules, and therapeutic modules. Based on these modules, five DNA kinds of representative nanomaterials applied in drug delivery were introduced, including DNA nanogel, DNA origami, DNA framework, DNA nanoflower, and DNA hybrid nanosphere. Finally, we discussed the challenges in the transition of DNA materials to clinical applications. We expect that this review can help readers to obtain a deeper understanding of DNA materials, and further promote the development of these intelligent materials to real world's application. This article is categorized under: Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

DNA Nanotechnology-Based Biosensors and Therapeutics

Over the past few decades, DNA nanotechnology engenders a vast variety of programmable nanostructures utilizing Watson-Crick base pairing. Due to their precise engineering, unprecedented programmability, and intrinsic biocompatibility, DNA nanostructures cannot only interact with small molecules, nucleic acids, proteins, viruses, and cancer cells, but also can serve as nanocarriers to deliver different therapeutic agents. Such addressability innate to DNA nanostructures enables their use in various fields of biomedical applications such as biosensors and cancer therapy. This review is begun with a brief introduction of the development of DNA nanotechnology, followed by a summary of recent applications of DNA nanostructures in biosensors and therapeutics. Finally, challenges and opportunities for practical applications of DNA nanotechnology are discussed.

Smart and Functionalized Development of Nucleic Acid-Based Hydrogels: Assembly Strategies, Recent Advances, and Challenges

Nucleic acid-based hydrogels that integrate intrinsic biological properties of nucleic acids and mechanical behavior of their advanced assemblies are appealing bioanalysis and biomedical studies for the development of new-generation smart biomaterials. It is inseparable from development and incorporation of novel structural and functional units. This review highlights different functional units of nucleic acids, polymers, and novel nanomaterials in the order of structures, properties, and functions, and their assembly strategies for the fabrication of nucleic acid-based hydrogels. Also, recent advances in the design of multifunctional and stimuli-responsive nucleic acid-based hydrogels in bioanalysis and biomedical science are discussed, focusing on the applications of customized hydrogels for emerging directions, including 3D cell cultivation and 3D bioprinting. Finally, the key challenge and future perspectives are outlined.

Improved Antiviral Activity of Classical Swine Fever Virus-Targeted siRNA by Tetrahedral Framework Nucleic Acid-Enhanced Delivery

DNA self-assembled nanostructures have been considered as effective vehicles for biomolecule delivery because of their excellent biocompatibility, cellular permeability, noncytotoxicity, and small size. Here, we report an efficient antiviral strategy with self-assembled tetrahedral framework nucleic acids (tFNAs) delivering small interfering RNA (t-siRNA) to silence classical swine fever virus (CSFV) gene in porcine host cells. In this study, two previously reported siRNAs, C3 and C6, specifically targeting the CSFV genome were selected and modified on tFNAs, respectively, and termed t-C3 and t-C6. Results indicate that t-C3 and t-C6 can inhibit the viral proliferation of CSFV in kidney derived porcine cells, PK-15, effectively and that inhibition was markedly stronger than free siRNA-C3 or siRNA-C6 only. In addition, the DNA nanostructure also has high cargo-carrying capacity, allowing to deliver multiple functional groups. To improve the antiviral ability of tFNAs, a dual-targeting DNA nanostructure t-C3-C6 was constructed and used to silence the CSFV gene in porcine host cells. This study found that t-C3-C6 can inhibit the viral release and replication, exhibiting outstanding anti-CSFV capabilities. Therefore, these dual-targeting tFNAs have great potential in virus therapy. This strategy not only provides a novel method to inhibit CSFV replication in porcine cells but also verifies that tFNAs are effective tools for delivery of antiviral elements, which have great application potential.