DNA Origami Frameworks Enabled Self-Protective siRNA Delivery for Dual Enhancement of Chemo-Photothermal Combination Therapy

Multifunctional theranostic glyconanoprobes for synergistic eradication of breast cancer

Theranostic agents hold great promise for personalized medicine by combining diagnostic and therapeutic functions. Herein, two novel multifunctional theranostic glyconanoprobes targeting breast cancer were engineered for synergistic dual chemo-gene therapy and triple chemo-gene-photothermal therapy. Upconversion nanoparticles (UCNPs) were prepared and coated with a Dox-loaded glycopeptide polymer (P-Dox) to form UCNP@P-Dox for improving stability. UCNP@MP-Dox equipped for triple therapy was prepared by combining UCNP@P-Dox with magnetic (Fe3O4, M) nanoparticles with photothermal properties. To regulate the expression of the anti-apoptotic Bcl-2 protein, both UCNP@P-Dox and UCNP@MP-Dox were loaded with anti-Bcl-2 siRNA. Impressive photothermal efficiency and good MRI contrast were demonstrated in preliminary evaluations. Moreover, the UCNP@P-Dox/siRNA nanoprobe for dual therapy was shown in preclinical studies to significantly increase anti-tumor efficacy. In vivo experiments in tumor-induced mice showed nanoprobe accumulation in tumors and enhanced antitumor efficacy with combinatorial therapy over Dox and siRNA alone. This study demonstrates the tumor-targeting capability of multifunctional theranostic glyconanoprobes, establishing chemo-gene synergy as a potent therapeutic strategy for breast cancer.

Correlation of precisely fabricated geometric characteristics of DNA-origami nanostructures with their cellular entry in human lens epithelial cells

Human lens epithelial cells (hLECs) are critical for lens transparency, and their aberrant metabolic activity and gene expression can lead to cataract. Intracellular delivery to hLECs, especially to sub-cellular organelles (e.g., mitochondrion and nucleus), is a key step in engineering cells for cell- and gene- based therapies. Despite a broad variety of nano- and microparticles can enter cells, their spatial characteristics relevant to cellular uptake and localization remains elusive. To investigate cellular internalization of nanostructures in hLECs, herein, DNA nanotechnology was exploited to precisely fabricate four distinct, mass-controlled DNA-origami nanostructures (DONs) through computer-aided design. Ensembled DONs included the rods, ring, triangle, and octahedron with defined geometric parameters of accessible surface area, effective volume, compactness, aspect ratio, size and vertex number. Atomic force microscopy and agarose gel electrophoresis showed that four DONs self-assembled within 3.5h with up to 59% yield and exhibited structural intactness in cell culture medium for 4 h. Flow cytometry analysis of four Cy5-labelled DONs in hLECs HLE-B3 found time-dependent cellular uptake over 2 h, among which the octahedron and triangle had higher cellular accumulation than the rod and ring. More importantly, the vertex number among other geometric parameters was positively correlated with cellular entry. Confocal images further revealed that four DONs had preferential localization at mitochondria to nucleus at 2 h in HLE-B3 cells, and the degree of their biodistribution varied among DONs as evidenced by Manders' correlation coefficient. This study demonstrates the DONs dependent cellular uptake and intracellular compartment localization in hLECs, heralding the future design of structure-modulating delivery of nanomedicine for ocular therapy.

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.

A Targeted Octahedral DNA Nanostructure Co-delivers siME3 and Doxorubicin to Enhance Collateral Lethality in ME2-Deficient Pancreatic Cancer

The genetic characteristics of pancreatic cancer (PC) are being revealed, but treatment strategies based on these profiles are developing slowly. About one-third of PC patients harbor SMAD4 mutations, with its homozygous deletions often accompanied by deletions of the malic enzyme 2 (ME2) gene, leading to upregulation of malic enzyme 3 (ME3) to eliminate reactive oxygen species (ROS). We designed an aptamer-modified octahedral DNA nanostructure for targeted co-delivery of siRNA targeting ME3 (siME3) and doxorubicin (DOX). This nanostructure targets the epidermal growth factor receptor (EGFR) on the membrane of PC cells. Upon internalization, siME3 and DOX are released intracellularly. The siME3 effectively inhibited ME3 expression, diminishing the tumor cells' capacity to clear ROS. Moreover, DOX further increases the level of cellular ROS, and the sustained accumulation of ROS ultimately leads to apoptosis of ME2-deficient PC cells. This targeting nanostructure shows potential for enhancing collateral lethality in this PC subgroup.

Doxorubicin-loaded DNA origami nanostructures: stability in vitreous and their uptake and toxicity in ocular cells

Biocompatibility and precise control over their size and shape make DNA origami nanostructures (DONs) promising for drug delivery applications. Whilst many investigations have focused on cancer treatment, this might not be the best fit for DONs that get degraded by nucleases in blood. In comparison, an eye is a uniquely isolated target organ, which could benefit from DONs to achieve and maintain therapeutic concentrations in diseases that threaten the eyesight of millions of patients every year. We investigated the loading of doxorubicin (DOX) as a model drug into three distinct DONs and tested their stability upon storage. Further, we chose one structure (24HB) to probe its stability under physiological conditions in cell media and porcine vitreous, before examining the uptake and effect of DOX-loaded 24HB (24HB-DOX) on the cell viability in a retinal cell line (ARPE-19). Similar to previous reports, the tested low μM loading concentrations of DOX resulted in high drug loadings of up to 34% (m/m), and remained mostly intact in water for at least 2 months at 4 °C. In cell media and porcine vitreous at 37 °C, however, 24HB required additional Mg2+ supplementation to avoid degradation and the loss of the attached fluorophores. With added Mg2+, 24HB remained stable in vitreous for 7 days at 37 °C. The treatment with 24HB-DOX was well tolerated by ARPE-19 cells, compared to the observed higher toxicity of free DOX. Uptake studies revealed, however, that in contrast to free DOX, very little 24HB-DOX was taken up by the cells. Instead, the particles were observed to attach around the cells. Hence, our results suggest that since the uptake seems to be the bottleneck for therapies using DONs, further strategies such as adding ocular targeting moieties are necessary to increase the uptake and efficacy of doxorubicin-loaded DONs.

Homologous Tumor Cell-Derived Biomimetic Nano-Trojan Horse Integrating Chemotherapy with Genetherapy for Boosting Triple-Negative Breast Cancer Therapy

Triple-negative breast cancer (TNBC) is a subtype of breast cancer that carries the worst prognosis and lacks specific therapeutic targets. To achieve accurate "cargos" delivery at the TNBC site, we herein constructed a novel biomimetic nano-Trojan horse integrating chemotherapy with gene therapy for boosting TNBC treatment. Briefly, we initially introduce the diselenide-bond-containing organosilica moieties into the framework of mesoporous silica nanoparticles (MONs), thereby conferring biodegradability to intratumoral redox conditions in the obtained MONSe. Subsequently, doxorubicin (Dox) and therapeutic miR-34a are loaded into MONSe, thus achieving the combination of chemotherapy and gene-therapy. After homologous tumor cell membrane coating, the ultimate homologous tumor cell-derived biomimetic nano-Trojan horse (namely, MONSe@Dox@miR-34a@CM) can selectively enter the tumor cells in a stealth-like fashion. Notably, such a nanoplatform not only synergistically eradicated the tumor but also inhibited the proliferation of breast cancer stem-like cells (BCSCs) in vitro and in vivo. With the integration of homologous tumor cell membrane-facilitated intratumoral accumulation, excellent biodegradability, and synergistic gene-chemotherapy, our biomimetic nanocarriers hold tremendous promise for the cure of TNBC in the future.

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.

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.

The Emerging Landscape for Combating Resistance Associated with Energy-Based Therapies via Nanomedicine

Cancer represents a serious disease with significant implications for public health, imposing substantial economic burden and negative societal consequences. Compared to conventional cancer treatments, such as surgery and chemotherapy, energy-based therapies (ET) based on athermal and thermal ablation provide distinct advantages, including minimally invasive procedures and rapid postoperative recovery. Nevertheless, due to the complex pathophysiology of many solid tumors, the therapeutic effectiveness of ET is often limited. Nanotechnology offers unique opportunities by enabling facile material designs, tunable physicochemical properties, and excellent biocompatibility, thereby further augmenting the outcomes of ET. Numerous nanomaterials have demonstrated the ability to overcome intrinsic therapeutic resistance associated with ET, leading to improved antitumor responses. This comprehensive review systematically summarizes the underlying mechanisms of ET-associated resistance (ETR) and highlights representative applications of nanoplatforms used to mitigate ETR. Overall, this review emphasizes the recent advances in the field and presents a detailed account of novel nanomaterial designs in combating ETR, along with efforts aimed at facilitating their clinical translation.

SiRNF8 Delivered by DNA Framework Nucleic Acid Effectively Sensitizes Chemotherapy in Colon Cancer

Background

The evident side effects and decreased drug sensitivity significantly restrict the use of chemotherapy. However, nanoparticles based on biomaterials are anticipated to address this challenge.

Methods

Through bioinformatics analysis and colon cancer samples, we initially investigated the expression level of RNF8 in colon cancer. Next, we constructed nanocarrier for delivering siRNF8 based on DNA tetrahedron (si-Tet), and Doxorubicin (DOX) was further intercalated into the DNA structure (si-DOX-Tet) for combination therapy. Further, the effects and mechanism of RNF8 inhibition on the sensitivity of colon cancer cells to DOX chemotherapy have also been studied.

Results

RNF8 expression was increased in colon cancer. Agarose gel electrophoresis, transmission electron microscopy, and size distribution and potential analysis confirmed the successful preparation of the two nanoparticles, with particle sizes of 10.29 and 37.29 nm, respectively. Fluorescence imaging reveals that the carriers can be internalized into colon cancer cells and escape from lysosomes after 12 hours of treatment, effectively delivering siRNF8 and DOX. Importantly, Western blot analysis verified treatment with 50nM si-Tet silenced RNF8 expression by approximately 50% in colon cancer cells, and combined treatment significantly inhibited cell proliferation. Furthermore, the CCK-8 assay demonstrated that si-Tet treatment enhanced the sensitivity of colon cancer cells to the three chemotherapeutic drugs. Significant more DNA damage was detected after treatment with both si-Tet or si-DOX-Tet. Further flow cytometry analysis revealed that si-DOX-Tet treatment led to significantly more apoptosis, approximately 1.6-fold higher than treatment with DOX alone. Mechanistically, inhibiting RNF8 led to decreased ABCG2 expression and DOX efflux, but increased DNA damage, thereby enhancing the chemotherapeutic effect of DOX.

Conclusion

We have successfully constructed si-DOX-Tet. By inhibiting the expression of RNF8, it enhances the chemotherapy sensitivity of DOX. Therefore, this tetrahedral FNA nanocarrier offers a new approach for the combined treatment of colon cancer.

A Comprehensive Review of Small Interfering RNAs (siRNAs): Mechanism, Therapeutic Targets, and Delivery Strategies for Cancer Therapy

Small interfering RNA (siRNA) delivery by nanocarriers has been identified as a promising strategy in the study and treatment of cancer. Short nucleotide sequences are synthesized exogenously to create siRNA, which triggers RNA interference (RNAi) in cells and silences target gene expression in a sequence-specific way. As a nucleic acid-based medicine that has gained popularity recently, siRNA exhibits novel potential for the treatment of cancer. However, there are still many obstacles to overcome before clinical siRNA delivery devices can be developed. In this review, we discuss prospective targets for siRNA drug design, explain siRNA drug properties and benefits, and give an overview of the current clinical siRNA therapeutics for the treatment of cancer. Additionally, we introduce the siRNA chemical modifications and delivery systems that are clinically sophisticated and classify bioresponsive materials for siRNA release in a methodical manner. This review will serve as a reference for researchers in developing more precise and efficient targeted delivery systems, promoting ongoing advances in clinical applications.

The Creation of DNA Origami-Based Supramolecular Nanostructures for Cancer Therapy

DNA origami technology, a unique type of DNA nanotechnology, has attracted much attention from researchers and is applied in various fields. Through exquisite design and precise self-assembly of four kinds of deoxyribonucleotides, DNA origami nanostructures are endowed with excellent programmability and addressability and show outstanding biocompatibility in bio-related applications, especially in cancer treatment. In this review, nanomaterials based on DNA origami for cancer therapy are concluded, whereby chemotherapy and photo-assisted therapy are the main focus. Furthermore, the working mechanisms of the functional materials attached to the rigid DNA structures to enable targeted delivery and circumvent drug resistance are also discussed. DNA origami nanostructures are valuable carriers for delivering multifunctional therapeutic agents and demonstrate great potential in cancer treatment both in vitro and in vivo. It is undoubted that DNA origami technology is a promising strategy for constructing versatile nanodevices in biological fields and will excel in human healthcare.

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.

Addressing the in vivo delivery of nucleic-acid nanostructure therapeutics

DNA and RNA nanostructures are being investigated as therapeutics, vaccines, and drug delivery systems. These nanostructures can be functionalized with guests ranging from small molecules to proteins with precise spatial and stoichiometric control. This has enabled new strategies to manipulate drug activity and to engineer devices with novel therapeutic functionalities. Although existing studies have offered encouraging in vitro or pre-clinical proof-of-concepts, establishing mechanisms of in vivo delivery is the new frontier for nucleic-acid nanotechnologies. In this review, we first provide a summary of existing literature on the in vivo uses of DNA and RNA nanostructures. Based on their application areas, we discuss current models of nanoparticle delivery, and thereby highlight knowledge gaps on the in vivo interactions of nucleic-acid nanostructures. Finally, we describe techniques and strategies for investigating and engineering these interactions. Together, we propose a framework to establish in vivo design principles and advance the in vivo translation of nucleic-acid nanotechnologies.

NIR/pH-triggered aptamer-functionalized DNA origami nanovehicle for imaging-guided chemo-phototherapy

Targeted chemo-phototherapy has received widespread attention in cancer treatment for its advantages in reducing the side effects of chemotherapeutics and improving therapeutic effects. However, safe and efficient targeted-delivery of therapeutic agents remains a major obstacle. Herein, we successfully constructed an AS1411-functionalized triangle DNA origami (TOA) to codeliver chemotherapeutic drug (doxorubicin, DOX) and a photosensitizer (indocyanine green, ICG), denoted as TOADI (DOX/ICG-loaded TOA), for targeted synergistic chemo-phototherapy. In vitro studies show that AS1411 as an aptamer of nucleolin efficiently enhances the nanocarrier's endocytosis more than 3 times by tumor cells highly expressing nucleolin. Subsequently, TOADI controllably releases the DOX into the nucleus through the photothermal effect of ICG triggered by near-infrared (NIR) laser irradiation, and the acidic environment of lysosomes/endosomes facilitates the release. The downregulated Bcl-2 and upregulated Bax, Cyt c, and cleaved caspase-3 indicate that the synergistic chemo-phototherapeutic effect of TOADI induces the apoptosis of 4T1 cells, causing ~ 80% cell death. In 4T1 tumor-bearing mice, TOADI exhibits 2.5-fold targeted accumulation in tumor region than TODI without AS1411, and 4-fold higher than free ICG, demonstrating its excellent tumor targeting ability in vivo. With the synergetic treatment of DOX and ICG, TOADI shows a significant therapeutic effect of ~ 90% inhibition of tumor growth with negligible systemic toxicity. In addition, TOADI presents outstanding superiority in fluorescence and photothermal imaging. Taken together, this multifunctional DNA origami-based nanosystem with the advantages of specific tumor targeting and controllable drug release provides a new strategy for enhanced cancer therapy.

Customized Scaffolds for Direct Assembly of Functionalized DNA Origami

Functional DNA origami nanoparticles (DNA-NPs) are used as nanocarriers in a variety of biomedical applications including targeted drug delivery and vaccine development. DNA-NPs can be designed into a broad range of nanoarchitectures in one, two, and three dimensions with high structural fidelity. Moreover, the addressability of the DNA-NPs enables the precise organization of functional moieties, which improves targeting, actuation, and stability. DNA-NPs are usually functionalized via chemically modified staple strands, which can be further conjugated with additional polymers and proteins for the intended application. Although this method of functionalization is extremely efficient to control the stoichiometry and organization of functional moieties, fewer than half of the permissible sites are accessible through staple modifications. In addition, DNA-NP functionalization rapidly becomes expensive when a high number of functionalizations such as fluorophores for tracking and chemical modifications for stability that do not require spatially precise organization are used. To facilitate the synthesis of functional DNA-NPs, we propose a simple and robust strategy based on an asymmetric polymerase chain reaction (aPCR) protocol that allows direct synthesis of custom-length scaffolds that can be randomly modified and/or precisely modified via sequence design. We demonstrated the potential of our strategy by producing and characterizing heavily modified scaffold strands with amine groups for dye functionalization, phosphorothioate bonds for stability, and biotin for surface immobilization. We further validated our sequence design approach for precise conjugation of biomolecules by synthetizing scaffolds including binding loops and aptamer sequences that can be used for direct hybridization of nucleic acid tagged biomolecules or binding of protein targets.

DNA Nanomaterials-Based Platforms for Cancer Immunotherapy

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

Unravelling the Drug Encapsulation Ability of Functional DNA Origami Nanostructures: Current Understanding and Future Prospects on Targeted Drug Delivery

Rapid breakthroughs in nucleic acid nanotechnology have always driven the creation of nano-assemblies with programmable design, potent functionality, good biocompatibility, and remarkable biosafety during the last few decades. Researchers are constantly looking for more powerful techniques that provide enhanced accuracy with greater resolution. The self-assembly of rationally designed nanostructures is now possible because of bottom-up structural nucleic acid (DNA and RNA) nanotechnology, notably DNA origami. Because DNA origami nanostructures can be organized precisely with nanoscale accuracy, they serve as a solid foundation for the exact arrangement of other functional materials for use in a number of applications in structural biology, biophysics, renewable energy, photonics, electronics, medicine, etc. DNA origami facilitates the creation of next-generation drug vectors to help in the solving of the rising demand on disease detection and therapy, as well as other biomedicine-related strategies in the real world. These DNA nanostructures, generated using Watson-Crick base pairing, exhibit a wide variety of properties, including great adaptability, precise programmability, and exceptionally low cytotoxicity in vitro and in vivo. This paper summarizes the synthesis of DNA origami and the drug encapsulation ability of functionalized DNA origami nanostructures. Finally, the remaining obstacles and prospects for DNA origami nanostructures in biomedical sciences are also highlighted.

Virus Mimetic Framework DNA as a Non-LNP Gene Carrier for Modulated Cell Endocytosis and Apoptosis

Mimicking the size and shape of spherical viruses, we constructed a soccer-ball shaped virus-inspired DNA origami (ViDO) framework as a programmable non-LNP (lipid nanoparticle) gene carrier. The DNA framework was decorated with precisely controlled recognition molecules outside and loaded with adequate genetic molecules inside. Five variants were constructed to systematically investigate their cell uptake and modulated gene silencing efficiency. Cellular uptake was enhanced with an increasing number of aptamers, while with a median number of aptamer supply, dispersed distribution performed better than the clustered pattern. Intriguingly, the transfection efficiency was maximized using the ViDO with clustered five aptamers, which exhibited a competitive RNA silencing effect induced by Lipo2000 with low cytotoxicity. Our results revealed the effects of aptamer distribution patterns on endocytosis and transfection, thus providing a programmable platform for meticulous optimization of the gene delivery system.

Functionalizing DNA origami to investigate and interact with biological systems

DNA origami has emerged as a powerful method to generate DNA nanostructures with dynamic properties and nanoscale control. These nanostructures enable complex biophysical studies and the fabrication of next-generation therapeutic devices. For these applications, DNA origami typically needs to be functionalized with bioactive ligands and biomacromolecular cargos. Here, we review methods developed to functionalize, purify, and characterize DNA origami nanostructures. We identify remaining challenges, such as limitations in functionalization efficiency and characterization. We then discuss where researchers can contribute to further advance the fabrication of functionalized DNA origami.

Nucleic acid-based artificial nanocarriers for gene therapy

Nucleic acid nanotechnology is a powerful tool in the fields of biosensing and nanomedicine owing to their high editability and easy synthesis and modification. Artificial nucleic acid nanostructures have become an emerging research hotspot as gene carriers with low cytotoxicity and immunogenicity for therapeutic approaches. In this review, recent progress in the design and functional mechanisms of nucleic acid-based artificial nano-vectors especially for exogenous siRNA and antisense oligonucleotide delivery is summarized. Different types of DNA nanocarriers, including DNA junctions, tetrahedrons, origami, hydrogels and scaffolds, are introduced. The enhanced targeting strategies to improve the delivery efficacy are demonstrated. Furthermore, RNA based gene nanocarrier systems by self-assembly of short strands, rolling circle transcription, chemical crosslinking and using RNA motifs and DNA-RNA hybrids are demonstrated. Finally, the outlook and potential challenges are highlighted. The nucleic acid-based artificial nanocarriers offer a promising and precise tool for gene delivery and therapy.

Protein encapsulation of nanocatalysts: A feasible approach to facilitate catalytic theranostics

Enzyme-mimicking nanocatalysts, also termed nanozymes, have attracted much attention in recent years. They are considered potential alternatives to natural enzymes due to their multiple catalytic activities and high stability. However, concerns regarding the colloidal stability, catalytic specificity, efficiency and biosafety of nanomaterials in biomedical applications still need to be addressed. Proteins are biodegradable macromolecules that exhibit superior biocompatibility and inherent bioactivities; hence, the protein modification of nanocatalysts is expected to improve their bioavailability to match clinical needs. The diversity of amino acid residues in proteins provides abundant functional groups for the conjugation or encapsulation of nanocatalysts. Moreover, protein encapsulation can not only improve the overall performance of nanocatalysts in biological systems, but also bestow materials with new features, such as targeting and retention in pathological sites. This review aims to report the recent developments and perspectives of protein-encapsulated catalysts in their functional improvements, modification methods and applications in biomedicine.

DNA Nanoribbon for Efficient Anti-miRNA Peptide Nucleic Acid Delivery and Synergistic Enhancement of Cancer Cell Apoptosis

Antisense peptide nucleic acid (asPNA), an effective antisense drug, has been employed as a gene therapy agent and a useful tool in molecular biology. Gaining control over the delivery of asPNA to target tissues has been a major hindrance to its wide application in clinical practice. A simple and efficient DNA nanoribbon (DNR)-based drug delivery process has been designed in this study that releases the asPNA agent to inhibit oncogenic microRNAs (miRNAs). Furthermore, we demonstrated how the AS1411 aptamer that binds nucleolin on the cell membranes works as a control mechanism capable of identifying target cancer cells and enhancing the enrichment capacity of DNR. With the biodegradability of DNR, we can efficiently initiate the release of asPNA into the cytoplasm, particularly targeting the intended miR-21 and synergistically increasing programmed cell death 4 (PDCD4) expression to enhance cell apoptosis. We assume that this well-defined delivery mechanism will aid in designing antisense site-specific treatments for various diseases, including cancer.

Recent advances in nanotechnology approaches for non-viral gene therapy

Gene therapy has shown great potential in the treatment of many diseases by downregulating the expression of certain genes. The development of gene vectors as a vehicle for gene therapy has greatly facilitated the widespread clinical application of nucleic acid materials (DNA, mRNA, siRNA, and miRNA). Currently, both viral and non-viral vectors are used as delivery systems of nucleic acid materials for gene therapy. However, viral vector-based gene therapy has several limitations, including immunogenicity and carcinogenesis caused by the exogenous viral vectors. To address these issues, non-viral nanocarrier-based gene therapy has been explored for superior performance with enhanced gene stability, high treatment efficiency, improved tumor-targeting, and better biocompatibility. In this review, we discuss various non-viral vector-mediated gene therapy approaches using multifunctional biodegradable or non-biodegradable nanocarriers, including polymer-based nanoparticles, lipid-based nanoparticles, carbon nanotubes, gold nanoparticles (AuNPs), quantum dots (QDs), silica nanoparticles, metal-based nanoparticles and two-dimensional nanocarriers. Various strategies to construct non-viral nanocarriers based on their delivery efficiency of targeted genes will be introduced. Subsequently, we discuss the cellular uptake pathways of non-viral nanocarriers. In addition, multifunctional gene therapy based on non-viral nanocarriers is summarized, in which the gene therapy can be combined with other treatments, such as photothermal therapy (PTT), photodynamic therapy (PDT), immunotherapy and chemotherapy. We also provide a comprehensive discussion of the biological toxicity and safety of non-viral vector-based gene therapy. Finally, the present limitations and challenges of non-viral nanocarriers for gene therapy in future clinical research are discussed, to promote wider clinical applications of non-viral vector-based gene therapy.

A mitochondria targeted cascade reaction nanosystem for improved therapeutic effect by overcoming cellular resistance

Mitigating cellular resistance, which could enhance the sensitivity of tumor cells to treatment, is a promising approach for obtaining better therapeutic outcomes. However, the present designs of materials generally disregard this point, or only focus on a single specific resistance. Herein, a strategy based on a series of cascade reactions aiming to suppress multiple cellular resistances is designed by integrating photothermal and chemotherapy into a mitochondria targeted nanosystem (AuBPs@TD). The intelligent nanosystem is fabricated by modifying gold nanobipyramids (AuBPs) with triphenylphosphonium (TPP) functionalized dichloroacetic acid (DCA). TPP serves as a "navigation system" and facilitates the location of AuBPs@TD in the mitochondria. Moreover, the released DCA promoted by the photothermal effect of AuBPs, as the mitochondrial kinase inhibitor, could inhibit glycolysis, and lead to a repressed expression of heat shock protein 90, which is the main resistance protein in cancer cells against photothermal therapy (PTT). Thus, the photothermal antitumor effect can be significantly improved. For the other cascade passage, the hyperthermal atmosphere depresses the expression of P-glycoprotein, a protein associated with drug resistance, and consequently prevents DCA molecules from being expelled in return. Furthermore, the retained DCA molecules elevate the concentration of intracellular hydrogen peroxide, and due to the peroxidase-like activity of AuBPs, increased intracellular reactive oxygen species could be obtained to accelerate apoptosis. As a result, these cascade reactions lead to significant inhibition of cellular resistance and greatly improve the therapeutic performance. This work paves a new way for suppressing cellular resistance to achieve the desired therapeutic effect.

Nucleic acid functionalized extracellular vesicles as promising therapeutic systems for nanomedicine

Extracellular vesicles (EVs), as natural carriers, are regarded as a new star in nanomedicine due to their excellent biocompatibility, fascinating physicochemical properties, and unique biological regulatory functions. However, there are still some challenges to using natural EVs, including poor targeting ability and the clearance from circulation, which may limit their further development and clinical use. Nucleic acid has the functions of programmability, targeting, gene therapy, and immune regulation. Owing to the engineering design and modification by integrating functional nucleic acid, EVs offer excellent performances as a therapeutic system in vivo. This review briefly introduces the function and mechanism of nucleic acid in the diagnosis and treatment of diseases. Then, the strategies of nucleic acid-functionalized EVs are summarized and the latest progress of nucleic acid-functionalized EVs in nanomedicine is highlighted. Finally, the challenges and prospects of nucleic acid-functionalized EVs as a promising diagnostic system are proposed.