Targeted Imaging of Brain Tumors with a Framework Nucleic Acid Probe

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.

Recent advances in chemical biology tools for protein and RNA profiling of extracellular vesicles

Extracellular vesicles (EVs) are nano-sized vesicles secreted by cells that contain various cellular components such as proteins, nucleic acids, and lipids from the parent cell. EVs are abundant in body fluids and can serve as circulating biomarkers for a variety of diseases or as a regulator of various biological processes. Considering these characteristics of EVs, analysis of the EV cargo has been spotlighted for disease diagnosis or to understand biological processes in biomedical research. Over the past decade, technologies for rapid and sensitive analysis of EVs in biofluids have evolved, but detection and isolation of targeted EVs in complex body fluids is still challenging due to the unique physical and biological properties of EVs. Recent advances in chemical biology provide new opportunities for efficient profiling of the molecular contents of EVs. A myriad of chemical biology tools have been harnessed to enhance the analytical performance of conventional assays for better understanding of EV biology. In this review, we will discuss the improvements that have been achieved using chemical biology tools.

A Microfluidic Chip-Based Automated System for Whole-Course Monitoring the Drug Responses of Organoids

Tumor patients-derived organoids, as a promising preclinical prediction model, have been utilized to evaluate ex vivo drug responses for formulating optimal therapeutic strategies. Detecting adenosine triphosphate (ATP) has been widely used in existing organoid-based drug response tests. However, all commercial ATP detection kits containing the cell lysis procedure can only be applied for single time point ATP detection, resulting in the neglect of dynamic ATP variations in living cells. Meanwhile, due to the limited number of viable organoids from a single patient, it is impractical to exhaustively test all potential time points in search of optimal ones. In this work, a multifunctional microfluidic chip was developed to perform all procedures of organoid-based drug response tests, including establishment, culturing, drug treatment, and ATP monitoring of organoids. An ATP sensor was developed to facilitate the first successful attempt on whole-course monitoring the growth status of fragile organoids. To realize a clinically applicable automatic system for the drug testing of lung cancer, a microfluidic chip based automated system was developed to perform entire organoid-based drug response test, bridging the gap between laboratorial manipulation and clinical practices, as it outperformed previous methods by improving data repeatability, eliminating human error/sample loss, and more importantly, providing a more accurate and comprehensive evaluation of drug effects.

Targeting HIF-1α with Specific DNA Yokes for Effective Anticancer Therapy

Hypoxia, a ubiquitous hallmark in cancer, underscores the significance of targeting HIF-1α, the principal transcriptional factor of hypoxic responses, for effective cancer therapy. Herein, DNA yokes, a novel class of DNA nanomaterials harboring specific HIF-1α binding sequences (hypoxia response elements, HREs), are introduced as nanopharmaceuticals for cancer treatment. Comprising a basal tetrahedral DNA nanostructure and four HRE-bearing overhanging chains, DNA yokes exhibit exceptional stability and prolonged intracellular retention. The investigation reveals their capacity to bind HIF-1α, thereby disrupting its interaction with the downstream genomic DNAs and impeding transcriptional activity. Moreover, DNA yokes facilitate HIF-1α degradation via the ubiquitination pathway, thereby sequestering it from downstream targets and ultimately promoting its degradation. In addition, DNA yokes attenuate cancer cell proliferation, migration, and invasion under hypoxic conditions, while also displaying preferential accumulation within tumors, thereby inhibiting tumor growth and metastasis in vivo. This study pioneers a novel approach to cancer therapy through the development of DNA-based drugs characterized by high stability and low toxicity to normal cells, positioning DNA yokes as promising candidates for cancer treatment.

Concept and Development of Algebraic Topological Framework Nucleic Acids

Nucleic acids are considered as promising materials for developing exquisite nanostructures from one to three dimensions. The advances of DNA nanotechnology facilitate ingenious design of DNA nanostructures with diverse shapes and sizes. Especially, the algebraic topological framework nucleic acids (ATFNAs) are functional DNA nanostructures that engineer guest molecules (e. g., nucleic acids, proteins, small molecules, and nanoparticles) stoichiometrically and spatially. The intrinsic precise properties and tailorable functionalities of ATFNAs hold great promise for biological applications, such as cell recognition and immunotherapy. This Perspective highlights the concept and development of precisely assembled ATFNAs, and outlines the new frontiers and opportunities for exploiting the structural advantages of ATFNAs for biological applications.

Cholesterol-Modified DNA Nanostructures Serve as Effective Non-Viral Carriers for Delivering siRNA to the Kidneys to Prevent Acute Kidney Injury

With the emergence of gene therapy utilizing viral vectors, the potential risks associated with these vectors have prompted increased attention toward non-viral alternatives. DNA nanotechnology enables the assembly of specific oligonucleotide chains into nanostructures possessing defined spatial configurations. Due to their inherent characteristics, DNA nanostructures possess natural advantages as carriers for regulating gene expression in a non-viral manner. Cholesterol modification can convert DNA nanostructures from hydrophilic materials to amphiphilic materials, thereby extending their systemic circulation time. In this study, the high-dimensional design and cholesterol modification are shown to prolong the systemic circulation half-life of DNA nanostructures in mice. Specifically, the tetrahedron structure modified with three cholesterol molecules (TDN-3Chol) exhibit excellent circulation time and demonstrate a preference for renal uptake. The unique characteristics of TDN-3Chol can effectively deliver p53 siRNA to the mouse renal tubular tissue, resulting in successful knockdown of p53 and demonstrating its potential for preventing acute kidney injury. Furthermore, TDN-3Chol is not exhibited significant toxicity in mice, highlighting its promising role as a non-viral vector for targeted gene expression regulation in the kidneys. The designed non-viral vector as a prophylactic medication shows potential in addressing the current clinical challenges associated with nephrotoxic drugs.

Enhancing Neuronal Cell Uptake of Therapeutic Nucleic Acids with Tetrahedral DNA Nanostructures

The successful translation of therapeutic nucleic acids (NAs) for the treatment of neurological disorders depends on their safe and efficient delivery to neural cells, in particular neurons. DNA nanostructures can be a promising NAs delivery vehicle. Nonetheless, the potential of DNA nanostructures for neuronal cell delivery of therapeutic NAs is unexplored. Here, tetrahedral DNA nanostructures (TDN) as siRNA delivery scaffolds to neuronal cells, exploring the influence of functionalization with two different reported neuronal targeting ligands: C4-3 RNA aptamer and Tet1 peptide are investigated. Nanostructures are characterized in vitro, as well as in silico using molecular dynamic simulations to better understand the overall TDN structural stability. Enhancement of neuronal cell uptake of TDN functionalized with the C4-3 Aptamer (TDN-Apt), not only in neuronal cell lines but also in primary neuronal cell cultures is demonstrated. Additionally, TDN and TDN-Apt nanostructures carrying siRNA are shown to promote silencing in a process aided by chloroquine-induced endosomal disruption. This work presents a thorough workflow for the structural and functional characterization of the proposed TDN as a nano-scaffold for neuronal delivery of therapeutic NAs and for targeting ligands evaluation, contributing to the future development of new neuronal drug delivery systems based on DNA nanostructures.

A covalent organic framework-derived M1 macrophage mimic nanozyme for precise tumor-targeted imaging and NIR-II photothermal catalytic chemotherapy

Nanoprobes for efficient tumor-targeted imaging and therapy are urgently needed for clinical tumor theranostics. Herein, inspired by the heterogeneity of the tumor microenvironment, we report a covalent organic framework (COF)-derived biomimetic nanozyme for precise tumor-targeted imaging and NIR-II photothermal-catalysis-enhanced chemotherapy (PTCEC). Using a crystalline nanoscale COF as the precursor, a peroxidase-like porous N-doped carbonous nanozyme (PNC) was obtained, which was cloaked with an M1 macrophage cell membrane (M1m) to create a multifunctional biomimetic nanoprobe for tumor-targeted imaging and therapy. The M1m coating enabled the nanoprobe to target cancer cells and tumor tissues for highly efficient tumor imaging and drug delivery. The peroxidase-like activity of the PNC allowed for the conversion of intratumoral H2O2 into toxic ˙OH that synergized with its NIR-II photothermal effect to strengthen the chemotherapy. Therefore, highly efficient tumor-targeted imaging and NIR-II PTCEC were realized with an M1 macrophage mimic nanoprobe. This work provides a feasible tactic for a biomimetic theranostic nanoprobe and will inspire the development of new bioactive nanomaterials for clinical tumor theranostic applications.

Noninvasive Framework Nucleic Acid Eye Drops for Retinal Administration

Intravitreal injection is widely employed for the treatment of retinal diseases. However, it suffers from various drawbacks, including ocular trauma, risk of infection, and poor patient compliance due to frequent administrations. Due to the presence of barriers such as the cornea, it has been a challenge to develop efficient noninvasive ophthalmic eye drops that can reach the retina. Framework nucleic acids (FNAs), known for their excellent biocompatibility and precise, controllable shape and size, have been extensively utilized in drug delivery application. Here, we report the development of size- and shape-resolved fluorescent DNA frameworks for noninvasive retinal administration. Results show that tetrahedral DNA nanostructures (TDNs) with an edge length of 20 bp can reach the retina within 6 h with the highest efficiency. Moreover, this delivery method exhibits excellent biocompatibility. Our findings provide an approach for the development of localized treatment strategies for retinal diseases using FNA-based nanocarriers.

Real-time monitoring ATP variation in human cancer organoids for a long term by DNA-based nanosensor

Cancer organoids have become promising tools for predicting drug responses on many different types of cancer. Detecting the adenosine triphosphate (ATP) has currently been considered as a decisive test to profile the growth status and drug responses of organoids. ATP profiling using commercial ATP detection kits, which involve cell lysis, can be performed at a single time spot, causing a clinical dilemma of selecting the optimal time spot to adopt diverse cancer types and patients. This study provides a feasible solution to this dilemma by developing a DNA-based ATP nanosensor to realize real-time ATP monitoring in organoids for a long term. The employment of DNA materials ensures high biocompatibility and low cytotoxicity, which are crucial for fragile organoids; The usage of tetrahedral DNA framework ensures cell permeability and intracellular ATP detection; The introduction of ATP-mediated molecular replacement ensures the high sensitivity and selectivity of ATP recognition. These features result in the first successful attempt on real-time monitoring ATP in organoids for up to 26 days and gaining growth status curves for the whole duration of a drug sensitivity test on human lung cancer organoids.

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.

Recent progress and application of the tetrahedral framework nucleic acid materials on drug delivery

INTRODUCTION

The application of DNA framework nucleic acid materials in the biomedical field has witnessed continual expansion. Among them, tetrahedral framework nucleic acids (tFNAs) have gained significant traction as the foremost biological vectors due to their superior attributes of editability, low immunogenicity, biocompatibility, and biodegradability. tFNAs have demonstrated promising results in numerous in vitro and in vivo applications.

AREAS COVERED

This review summarizes the latest research on tFNAs in drug delivery, including a discussion of the advantages of tFNAs in regulating biological behaviors, and highlights the updated development and advantageous applications of tFNAs-based nanostructures from static design to dynamically responsive design.

EXPERT OPINION

tFNAs possess distinct biological regulatory attributes and can be taken up by cells without the requirement of transfection, differentiating them from other biological vectors. tFNAs can be easily physically/chemically modified and seamlessly incorporated with other functional systems. The static design of the tFNAs-based drug delivery system makes it versatile, reproducible, and predictable. Further use of the dynamic response mechanism of DNA to external stimuli makes tFNAs-based drug delivery more effective and specific, improving the uptake and utilization of the payload by the intended target. Dynamic targeting is poised to become the future primary approach for drug delivery.

Oncogene-targeting nanoprobes for early imaging detection of tumor

Malignant tumors have been one of the major reasons for deaths worldwide. Timely and accurate diagnosis as well as effective intervention of tumors play an essential role in the survival of patients. Genomic instability is the important foundation and feature of cancer, hence, in vivo oncogene imaging based on novel probes provides a valuable tool for the diagnosis of cancer at early-stage. However, the in vivo oncogene imaging is confronted with great challenge, due to the extremely low copies of oncogene in tumor cells. By combining with various novel activatable probes, the molecular imaging technologies provide a feasible approach to visualize oncogene in situ, and realize accurate treatment of tumor. This review aims to declare the design of nanoprobes responded to tumor associated DNA or RNA, and summarize their applications in detection and bioimaging for tumors. The significant challenges and prospective of oncogene-targeting nanoprobes towards tumors diagnosis are revealed as well.

DNA Tetrahedra-Based Delivery of MicroRNA-22 to Reduce Depressive Symptoms in Mice

Major depressive disorder (MDD) is a common illness with an increasing lifetime prevalence. Thus, an increasing number of studies have investigated the association between MDD and microRNAs (miRNAs), which are a novel approach for treating depression. However, the therapeutic potential of miRNA-based strategies has several limitations. To overcome these limitations, DNA tetrahedra (TDNs) have been used as piggyback materials. In this study, we successfully used TDNs as carriers of miRNA-22-3p (miR-22-3p) and synthesized a novel DNA nanocomplex (TDN-miR-22-3p), which was used in a lipopolysaccharide (LPS)-induced depression cell model. The results suggest that miR-22-3p may regulate inflammation by regulating phosphatase and tensin homologue (PTEN), an important regulatory molecule in the PI3K/AKT pathway, and downregulating the expression of NLRP3. We further validated the role of TDN-miR-22-3p in vivo using an LPS-induced animal model of depression. The results indicate that it ameliorated depression-like behavior and attenuated the expression of inflammation-related factors in mice. This study demonstrates the establishment of a straightforward and efficacious miRNA delivery system and the potential of TDNs as therapeutic vectors and tools for mechanistic studies. To the best of our knowledge, this is the first study to use TDNs in combination with miRNAs to treat depression.

Programing Immunogenic Cell Death in Breast Tumors with Designer DNA Frameworks

The low response rate and serious side effects of cancer treatment pose significant limitations in immunotherapy. Here, we developed a multifunctional tetrahedral DNA framework (TDF) as a drug carrier to recruit chemotherapeutants and trigger immunogenic cell death (ICD) effects, which could turn tumors from cold to hot to boost the efficacy of antitumor immunotherapy. A tumor-targeting peptide RGD was modified on the TDF to increase the delivery efficiency, and the chemotherapeutant doxorubicin (DOX) was loaded to induce ICD effects, which were assisted by the immune adjuvant of CpG immunologic sequences linked on TDF. We demonstrated that the multifunctional TDF could suppress 4T1 breast tumor growth by increasing tumor infiltration of CD8⁺ T cells, upregulating granzyme B and perforin expressions to twice as much as the control group, and decreasing 30% CD25⁺ Treg cells. Furthermore, the combination of α-PD-1 could inhibit the growth of distant tumor and suppressed tumor recurrence in a bilateral syngeneic 4T1 mouse model; the distant tumor weight inhibition rate was about 91.6%. Hence, through quantitatively targeting the delivery of DOX to reduce the side effects of chemotherapy and sensitizing the immune response by ICD effects, this multifunctional TDF therapeutic strategy displayed better treatment effect and a promising clinical application prospect.

Nucleic acid nanostructures for in vivo applications: The influence of morphology on biological fate

The development of programmable biomaterials for use in nanofabrication represents a major advance for the future of biomedicine and diagnostics. Recent advances in structural nanotechnology using nucleic acids have resulted in dramatic progress in our understanding of nucleic acid-based nanostructures (NANs) for use in biological applications. As the NANs become more architecturally and functionally diverse to accommodate introduction into living systems, there is a need to understand how critical design features can be controlled to impart desired performance in vivo. In this review, we survey the range of nucleic acid materials utilized as structural building blocks (DNA, RNA, and xenonucleic acids), the diversity of geometries for nanofabrication, and the strategies to functionalize these complexes. We include an assessment of the available and emerging characterization tools used to evaluate the physical, mechanical, physiochemical, and biological properties of NANs in vitro. Finally, the current understanding of the obstacles encountered along the in vivo journey is contextualized to demonstrate how morphological features of NANs influence their biological fates. We envision that this summary will aid researchers in the designing novel NAN morphologies, guide characterization efforts, and design of experiments and spark interdisciplinary collaborations to fuel advancements in programmable platforms for biological applications.

Self-Assembled Artificial DNA Nanocompartments and Their Bioapplications

Compartmentalization is the strategy evolved by nature to control reactions in space and time. The ability to emulate this strategy through synthetic compartmentalization systems has rapidly evolved in the past years, accompanied by an increasing understanding of the effects of spatial confinement on the thermodynamic and kinetic properties of the guest molecules. DNA nanotechnology has played a pivotal role in this scientific endeavor and is still one of the most promising approaches for the construction of nanocompartments with programmable structural features and nanometer-scaled addressability. In this review, the design approaches, bioapplications, and theoretical frameworks of self-assembled DNA nanocompartments are surveyed. From DNA polyhedral cages to virus-like capsules, the construction principles of such intriguing architectures are illustrated. Various applications of DNA nanocompartments, including their use for programmable enzyme scaffolding, single-molecule studies, biosensing, and as artificial nanofactories, ending with an ample description of DNA nanocages for biomedical purposes, are then reported. Finally, the theoretical hypotheses that make DNA nanocompartments, and nanosystems in general, a topic of great interest in modern science, are described and the progresses that have been done until now in the comprehension of the peculiar phenomena that occur within nanosized environments are summarized.

Framework Nucleic Acids as Blood-Retinal-Barrier-Penetrable Nanocarrier for Periocular Administration

Designing an ocular drugs delivery system that can permeate the outer blood-retinal barrier (oBRB) is crucial for the microinvasive or noninvasive treatment of ocular fundus diseases. However, due to the lack of a nanocarrier that can maintain structure and composition at the oBRB, only intravitreal injection at the eyeball can deliver therapeutics directly to the ocular fundus via paracellular and intercellular routes, despite the intraocular operations risks. Here, we demonstrated tetrahedral framework nucleic acids (tFNAs) can penetrate the oBRB and deliver therapeutic nucleic acids to the retina of the rat eye in vivo following subconjunctival injection. We also discovered that tFNAs were transported via a paracellular route across the intercellular tight junctions at the oBRB. The histology analysis for ocular layers indicated that individual and aptamer/doxorubicin-loaded tFNAs penetrated all layers of the posterior segment of the eyeball to reach the innermost retina and persisted for over 3 days with minimal systemic biodistribution. We expect that the programmability and penetrability of tFNAs will provide a promising method for drug delivery across oBRB and long-term sustenance at the target site via periocular administration to various tissues.

Synthesis of tetrahedron DNA nanostructures for detecting the activation of cell signal transduction via their specific binding to transcriptional factors

A technique for detecting the activation of cell signal transduction is particularly important for disease diagnosis and therapy. Transcriptional factor (TF) activities that could indicate the status of cell signal transduction are a favorable target for cell signal detection. Tetrahedron DNA nanostructures (TDNs) which contain specific binding sequences of TFs were designed and synthesized in this research, and their effects on detecting cell signal transduction were evaluated. We found that FAM-labeled TDNs with the indicated TF binding sequences could specifically bind to activated TFs of hypoxia signaling or TGF-β signaling. Signaling pathway activities detected via TDNs could be exhibited by various methods including fluorescence imaging, flow cytometry and fluorescence spectrometer analysis. The reliability of this new technique is in line with the classical dual luciferase reporter assay system. This work develops a novel and effective tool to examine the activation of intracellular signaling pathways via nanotechnology. In addition, good stability and programmability of TDNs ensure their widespread application in various signaling pathways.

Peptides as Pharmacological Carriers to the Brain: Promises, Shortcomings and Challenges

Central nervous system (CNS) diseases are among the most difficult to treat, mainly because the vast majority of the drugs fail to cross the blood-brain barrier (BBB) or to reach the brain at concentrations adequate to exert a pharmacological activity. The obstacle posed by the BBB has led to the in-depth study of strategies allowing the brain delivery of CNS-active drugs. Among the most promising strategies is the use of peptides addressed to the BBB. Peptides are versatile molecules that can be used to decorate nanoparticles or can be conjugated to drugs, with either a stable link or as pro-drugs. They have been used to deliver to the brain both small molecules and proteins, with applications in diverse therapeutic areas such as brain cancers, neurodegenerative diseases and imaging. Peptides can be generally classified as receptor-targeted, recognizing membrane proteins expressed by the BBB microvessels (e.g., Angiopep2, CDX, and iRGD), "cell-penetrating peptides" (CPPs; e.g. TAT_47-57, SynB1/3, and Penetratin), undergoing transcytosis through unspecific mechanisms, or those exploiting a mixed approach. The advantages of peptides have been extensively pointed out, but so far few studies have focused on the potential negative aspects. Indeed, despite having a generally good safety profile, some peptide conjugates may display toxicological characteristics distinct from those of the peptide itself, causing for instance antigenicity, cardiovascular alterations or hemolysis. Other shortcomings are the often brief lifetime in vivo, caused by the presence of peptidases, the vulnerability to endosomal/lysosomal degradation, and the frequently still insufficient attainable increase of brain drug levels, which remain below the therapeutically useful concentrations. The aim of this review is to analyze not only the successful and promising aspects of the use of peptides in brain targeting but also the problems posed by this strategy for drug delivery.

Delivery of DNA octahedra enhanced by focused ultrasound with microbubbles for glioma therapy

DNA nanostructures, with good biosafety, highly programmable assembly, flexible modification, and precise control, are tailored as drug carriers to deliver therapeutic agents for cancer therapy. However, they face considerable challenges regarding their delivery into the brain, mainly due to the blood-brain barrier (BBB). By controlling the acoustic parameters, focused ultrasound combined with microbubbles (FUS/MB) can temporarily, noninvasively, and reproducibly open the BBB in a localized region. We investigated the delivery outcome of pH-responsive DNA octahedra loading Epirubicin (Epr@DNA-Octa) via FUS/MB and its therapeutic efficiency in a mouse model bearing intracranial glioma xenograft. Using FUS/MB to locally disrupt the BBB or the blood-tumor barrier (BTB) and systemic administration of Epr@DNA-Octa (Epr@DNA-Octa + FUS/MB) (2 mg/kg of loaded Epr), we achieved an Epr concentration of 292.3 ± 10.1 ng/g tissue in glioma, a 4.4-fold increase compared to unsonicated animals (p < 0.001). The in vitro findings indicated that Epr released from DNA strands accumulated in lysosomes and induced enhanced cytotoxicity compared to free Epr. Further two-photon intravital imaging of spatiotemporal patterns of the DNA-Octa leakage revealed that the FUS/MB treatment enhanced DNA-Octa delivery across several physiological barriers at microscopic level, including the first extravasation across the BBB/BTB and then deep penetration into the glioma center and engulfment of DNA-Octa into the tumor cell body. Longitudinal in vivo bioluminescence imaging and histological analysis indicated that the intracranial glioma progression in nude mice treated with Epr@DNA-Octa + FUS/MB was effectively retarded compared to other groups. The beneficial effect on survival was most significant in the Epr@DNA-Octa + FUS/MB group, with a 50% increase in median survival and a 73% increase in the maximum survival compared to control animals. Our work demonstrates the potential viability of FUS/MB as an alternative strategy for glioma delivery of anticancer drugs using DNA nanostructures as the drug delivery platform for brain cancer therapy.

Structured Aptamers: A Flourishing Nanomaterial for Tumor Targeting

Structured aptamers are nucleic acid systems produced using DNA nano self-assembly technology and can be constructed in a programmable manner. These aptamers are widely used in biomedical fields because of their low biological toxicity, weak immunogenicity, good cytocompatibility and biocompatibility, stability, and facile modification ability. Additionally, structured aptamers achieve nano precision in spatial configuration and can be directly internalized into targets without the assistance of transfection reagents. They exhibit higher stability, rigidity, and binding efficiency than aptamers alone. Therefore, structured aptamers have been universally applied in the tumor-targeting field and have emerged as a current research hotspot. Here, we introduce the assembly principle, assembly methods, and characterization methods of structured aptamers. Moreover, the application status of structured aptamers for tumor detection and targeted therapy is summarized to provide new research directions for early diagnosis and drug research in the field of oncology.

Protein scaffolds: Antibody alternative for cancer diagnosis and therapy

Although antibodies are well developed and widely used in cancer therapy and diagnostic fields, some defects remain, such as poor tissue penetration, long in vivo metabolic retention, potential cytotoxicity, patent limitation, and high production cost. These issues have led scientists to explore and develop novel antibody alternatives. Protein scaffolds are small monomeric proteins with stable tertiary structures and mutable residues, which emerged in the 1990s. By combining robust gene engineering and phage display techniques, libraries with sufficient diversity could be established for target binding scaffold selection. Given the properties of small size, high affinity, and excellent specificity and stability, protein scaffolds have been applied in basic research, and preclinical and clinical fields over the past two decades. To date, more than 20 types of protein scaffolds have been developed, with the most frequently used being affibody, adnectin, ANTICALIN®, DARPins, and knottin. In this review, we focus on the protein scaffold applications in cancer therapy and diagnosis in the last 5 years, and discuss the pros and cons, and strategies of optimization and design.

Although antibodies are well developed and widely used in cancer therapy and diagnostic fields, some defects remain, such as poor tissue penetration, long in vivo metabolic retention, potential cytotoxicity, patent limitation, and high production cost.

Novel brain-targeted nanomicelles for anti-glioma therapy mediated by the ApoE-enriched protein corona in vivo

Background

The interactions between nanoparticles (NPs) and plasma proteins form a protein corona around NPs after entering the biological environment, which provides new biological properties to NPs and mediates their interactions with cells and biological barriers. Given the inevitable interactions, we regard nanoparticle‒protein interactions as a tool for designing protein corona-mediated drug delivery systems. Herein, we demonstrate the successful application of protein corona-mediated brain-targeted nanomicelles in the treatment of glioma, loading them with paclitaxel (PTX), and decorating them with amyloid β-protein (Aβ)-CN peptide (PTX/Aβ-CN-PMs). Aβ-CN peptide, like the Aβ_1–42 peptide, specifically binds to the lipid-binding domain of apolipoprotein E (ApoE) in vivo to form the ApoE-enriched protein corona surrounding Aβ-CN-PMs (ApoE/PTX/Aβ-CN-PMs). The receptor-binding domain of the ApoE then combines with low-density lipoprotein receptor (LDLr) and LDLr-related protein 1 receptor (LRP1r) expressed in the blood–brain barrier and glioma, effectively mediating brain-targeted delivery.

Methods

PTX/Aβ-CN-PMs were prepared using a film hydration method with sonication, which was simple and feasible. The specific formation of the ApoE-enriched protein corona around nanoparticles was characterized by Western blotting analysis and LC–MS/MS. The in vitro physicochemical properties and in vivo anti-glioma effects of PTX/Aβ-CN-PMs were also well studied.

Results

The average size and zeta potential of PTX/Aβ-CN-PMs and ApoE/PTX/Aβ-CN-PMs were 103.1 nm, 172.3 nm, 7.23 mV, and 0.715 mV, respectively. PTX was efficiently loaded into PTX/Aβ-CN-PMs, and the PTX release from rhApoE/PTX/Aβ-CN-PMs exhibited a sustained-release pattern in vitro. The formation of the ApoE-enriched protein corona significantly improved the cellular uptake of Aβ-CN-PMs on C6 cells and human umbilical vein endothelial cells (HUVECs) and enhanced permeability to the blood–brain tumor barrier in vitro. Meanwhile, PTX/Aβ-CN-PMs with ApoE-enriched protein corona had a greater ability to inhibit cell proliferation and induce cell apoptosis than taxol. Importantly, PTX/Aβ-CN-PMs exhibited better anti-glioma effects and tissue distribution profile with rapid accumulation in glioma tissues in vivo and prolonged median survival of glioma-bearing mice compared to those associated with PMs without the ApoE protein corona.

Conclusions

The designed PTX/Aβ-CN-PMs exhibited significantly enhanced anti-glioma efficacy. Importantly, this study provided a strategy for the rational design of a protein corona-based brain-targeted drug delivery system. More crucially, we utilized the unfavorable side of the protein corona and converted it into an advantage to achieve brain-targeted drug delivery.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01097-8.

Tetrahedral DNA nanostructures for effective treatment of cancer: advances and prospects

Recently, DNA nanostructures with vast application potential in the field of biomedicine, especially in drug delivery. Among these, tetrahedral DNA nanostructures (TDN) have attracted interest worldwide due to their high stability, excellent biocompatibility, and simplicity of modification. TDN could be synthesized easily and reproducibly to serve as carriers for, chemotherapeutic drugs, nucleic acid drugs and imaging probes. Therefore, their applications include, but are not restricted to, drug delivery, molecular diagnostics, and biological imaging. In this review, we summarize the methods of functional modification and application of TDN in cancer treatment. Also, we discuss the pressing questions that should be targeted to increase the applicability of TDN in the future.

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

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

DNAzyme Cleavage of CAG Repeat RNA in Polyglutamine Diseases

CAG repeat expansion is the genetic cause of nine incurable polyglutamine (polyQ) diseases with neurodegenerative features. Silencing repeat RNA holds great therapeutic value. Here, we developed a repeat-based RNA-cleaving DNAzyme that catalyzes the destruction of expanded CAG repeat RNA of six polyQ diseases with high potency. DNAzyme preferentially cleaved the expanded allele in spinocerebellar ataxia type 1 (SCA1) cells. While cleavage was non-allele-specific for spinocerebellar ataxia type 3 (SCA3) cells, treatment of DNAzyme leads to improved cell viability without affecting mitochondrial metabolism or p62-dependent aggresome formation. DNAzyme appears to be stable in mouse brain for at least 1 month, and an intermediate dosage of DNAzyme in a SCA3 mouse model leads to a significant reduction of high molecular weight ATXN3 proteins. Our data suggest that DNAzyme is an effective RNA silencing molecule for potential treatment of multiple polyQ diseases.

Proteomic Exploration of Endocytosis of Framework Nucleic Acids

Efficient cell internalization of framework nucleic acid nanostructures free of transfection agents provides new opportunities for developing biocompatible and intelligent nanoprobes and drug delivery carriers. Here, a proteomic identification method to screen target proteins that interact with tetrahedral DNA nanostructures (TDNs) during the process of endocytosis by combining drug affinity responsive target stability (DARTS) with liquid chromatography/tandem mass spectrometry (LC-MS/MS) techniques, is reported. It is found that that caveolin-1 (CAV1) and macropinocytosis-related protein sorting nexin5 (SNX5) are associated with the endocytosis of TNDs, which is further validated by microscale thermophoresis (MST) analysis. CAV1- and SNX5- knockout experiments reveal that both caveolae-mediated endocytosis and macropinocytosis mediate the cellular uptake of TDNs, which complement previous findings with fluorescence tracing methods. This method provides a generic strategy to analyze cellular internalization process of DNA nanostructures for biomedical applications.

Ultrasensitive electrochemical detection of miRNA coupling tetrahedral DNA modified gold nanoparticles tags and catalyzed hairpin assembly

MicroRNAs (miRNAs) play key regulatory roles in a number of biological processes, which act as critical biomarkers for clinical diagnosis. There are urgent needs to develop advanced tools for accurate and convenient analysis of miRNA in biological circumstances. In this study, an ultrasensitive electrochemical biosensor for miRNA assay is fabricated. Tetrahedral DNA modified gold nanoparticles tags are applied with optimized orientation, which are able to recruit a large number of electrochemical species for remarkable signal responses. Benefiting from the excellent amplification efficiency of the association of strand displacement amplification and catalyzed hairpin assembly, the established method shows ultrahigh sensitivity with the limit of detection as low as 10 aM. A wide linear range from 10^-17 to 10^-7 M is achieved. In addition, this method is capable to specifically discriminate interfering miRNAs with slightly different sequences. The successful assessment of miRNA levels in human serum samples also demonstrates good practical utility. Therefore, the proposed method has great potential to the applications of miRNA expression profiling and biological studies.

Self-Assembled DNA Nanostructure as a Carrier for Targeted siRNA Delivery in Glioma Cells

INTRODUCTION

RNA interference is a promising therapy in glioma treatment. However, the application of RNA interference has been limited in glioma therapy by RNA instability and the lack of tumor targeting. Here, we report a novel DNA tetrahedron, which can effectively deliver small interfering RNA to glioma cells and induce apoptosis.

METHODS

siRNA, a small interfering RNA that can suppress the expression of survivin in glioma, was loaded into the DNA tetrahedron (TDN). To enhance the ability of active targeting of this nanoparticle, we modified one side of the DNA nanostructure with aptamer as1411 (As-TDN-R), which can selectively recognize the nucleolin in the cytomembrane of tumor cells. The modified nanoparticles were characterized by agarose gel electrophoresis, dynamic light scattering, and transmission electron microscopy. The serum stability was evaluated by agarose gel electrophoresis. Nucleolin was detected by Western blot and immunofluorescence, and targeted cellular uptake was examined by flow cytometry. The TUNEL assay, flow cytometry, and Western Blot were used to detect apoptosis in U87 cells. The gene silencing of survivin was examined by qPCR, Western Blot, and immunofluorescence.

RESULTS

As-TDN-R alone showed better stability towards siRNA, indicating that TDN was a good siRNA protector. Compared with TDN alone, there was increased intercellular uptake of As-TDN-R by U87 cells, evidenced by overexpressed nucleolin in glioma cell lines. TUNEL assay, flow cytometry, and Western Blot revealed increased apoptosis in the As-TDN-R group. The downregulation of survivin protein and mRNA expression levels indicated that As-TDN-R effectively silenced the target gene.

CONCLUSION

The novel nanoparticle can serve as a good carrier for targeting siRNA delivery in glioma. Further exploration of the DNA nanostructure can greatly promote the application of DNA-based drug systems in glioma.

Targeted brain tumor imaging by using discrete biopolymer-coated nanodiamonds across the blood-brain barrier

Short circulation lifetime, poor blood-brain barrier (BBB) permeability and low targeting specificity limit nanovehicles from crossing the vascular barrier and reaching the tumor site. Consequently, the precise diagnosis of malignant brain tumors remains a great challenge. This study demonstrates the imaging of photostable biopolymer-coated nanodiamonds (NDs) with tumor targeting properties inside the brain. NDs are labeled with PEGylated denatured bovine serum albumin (BSA) and tumor vasculature targeting tripeptides RGD. The modified NDs show high colloidal stability in different buffer systems. Moreover, it is found that discrete dcBSA-PEG-NDs cross the in vitro BBB model more effectively than aggregated NDs. Importantly, compared with the non-targeting NDs, RGD-dcBSA-PEG-NDs can selectively target the tumor site in U-87 MG bearing mice after systemic injection. Overall, this discrete ND system enables efficacious brain tumor visualization with minimal toxicity to other major organs, and is worthy of further investigation into the applications as a unique platform for noninvasive theragnostics and/or thermometry at different stages of human diseases in the brain.

DNA nanotechnology-empowered nanoscopic imaging of biomolecules

DNA nanotechnology has led to the rise of DNA nanostructures, which possess programmable shapes and are capable of organizing different functional molecules and materials. A variety of DNA nanostructure-based imaging probes have been developed.

A brain glioma gene delivery strategy by angiopep-2 and TAT-modified magnetic lipid-polymer hybrid nanoparticles

Owing to the existence of the blood-brain barrier (BBB), most treatments cannot achieve significant effects on gliomas. In this study, synergistic multitarget Ang-TAT-Fe3O4-pDNA-(ss)373 lipid-polymer hybrid nanoparticles (LPNPs) were designed to penetrate the BBB and deliver therapeutic genes to glioma cells. The basic material of the nanoparticles was PCL3750-ss-PEG7500-ss-PCL3750, and is called (ss)373 herein. (ss)373 NPs, Fe3O4 magnetic nanoparticles (MNPs), DOTAP, and DSPE-PEG-MAL formed the basic structure of LPNPs by self-assembly. The Fe3O4 MNPs were wrapped in (ss)373 NPs to implement magnetic targeting. Then, the Angiopep-2 peptide (Ang) and transactivator of transcription (TAT) were coupled with DSPE-PEG-MAL. Both can enhance BBB penetration and tumor targeting. Finally, the pDNA was compressed on DOTAP to form the complete gene delivery system. The results indicated that the Ang-TAT-Fe3O4-pDNA-(ss)373 LPNPs were 302.33 nm in size. In addition, their zeta potential was 4.66 mV, and they had good biocompatibility. The optimal nanoparticles/pDNA ratio was 5 : 1, as shown by gel retardation assay. In this characterization, compared with other LPNPs, the modified single Ang or without the addition of the Fe3O4 MNPs, the penetration efficiency of the BBB model formed by hCMEC/D3 cells, and the transfection efficiency of C6 cells using pEGFP-C1 as the reporter gene were significantly improved with Ang-TAT-Fe3O4-pDNA-(ss)373 LPNPs in the magnetic field.

Brain delivery of Plk1 inhibitor via chimaeric polypeptide polymersomes for safe and superb treatment of orthotopic glioblastoma

The chemotherapy toward glioblastoma (GBM) is severely challenged by blood-brain barrier and dose-limiting toxicity. Herein, we adopt brain delivery of Plk1 inhibitor volasertib (Vol), which is highly specific and presents low off-target toxicity, as a new means to treat GBM, for which angiopep-2-docked chimaeric polypeptide polymersome (ANG-CPP) was designed and prepared from poly(ethylene glycol)-b-poly(L-tyrosine)-b-poly(L-aspartic acid) for loading Vol to its watery interior via electrostatic interactions. ANG-CPP loaded with 13.9 wt% Vol (ANG-CPP-Vol) exhibited a small size of about 76 nm, superb colloidal stability (against dilution, serum and long-term storage), and enzyme-triggered drug release behavior (about 73% of Vol released within 8 h with proteinase K). In sharp contrast to free Vol, ANG-CPP-Vol induced complete G2/M cell cycle arrest in U-87 MG GBM cells giving 7.8-times better anti-tumor activity, prolonged circulation time and largely increased GBM enrichment. ANG-CPP-Vol effectively suppressed the growth of orthotopic U-87 MG GBM and significantly boosted mice survival rate. Importantly, ANG-CPP-Vol showed further reduced toxicity over free Vol. This great safety and remarkable efficacy of ANG-CPP-Vol renders it a high potential for treating GBM.

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

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

DNA Framework-Supported Electrochemical Analysis of DNA Methylation for Prostate Cancers

Epigenetic alterations hold great promise as biomarkers for early stage cancer diagnosis. Nevertheless, direct identification of rare methylated DNA in the genome remains challenging. Here, we report an ultrasensitive framework nucleic acid-based electrochemical sensor for quantitative and highly selective analysis of DNA methylation. Notably, we can detect 160 fg of methylated DNA in million-fold unmethylated DNA samples using this electrochemical methylation-specific polymerase chain reaction (E-MSP) method. The high sensitivity of E-MSP enables one-step detection of low-abundance methylation at two different genes in patient serum samples. By using a combination test with two methylation alterations, we achieve high accuracy and sensitivity for reliable differentiation of prostate cancer and benign prostate hypertrophy (BPH). This new method sheds new light on translational use in early cancer diagnosis and in monitoring patients' responses to therapeutic agents.

Rationally Designed DNA Nanostructures for Drug Delivery

DNA is an excellent biological material that has received growing attention in the field of nanotechnology due to its unique capability for precisely engineering materials via sequence specific interactions. Self-assembled DNA nanostructures of prescribed physicochemical properties have demonstrated potent drug delivery efficiency in vitro and in vivo. By using various conjugation techniques, DNA nanostructures may be precisely integrated with a large diversity of functional moieties, such as targeting ligands, proteins, and inorganic nanoparticles, to enrich their functionalities and to enhance their performance. In this review, we start with introducing strategies on constructing DNA nanostructures. We then summarize the biological barriers ahead of drug delivery using DNA nanostructures, followed by introducing existing rational solutions to overcome these biological barriers. Lastly, we discuss challenges and opportunities for DNA nanostructures toward real applications in clinical settings.

Gint4.T-Modified DNA Tetrahedrons Loaded with Doxorubicin Inhibits Glioma Cell Proliferation by Targeting PDGFRβ

Glioma is one of the deadliest intrinsic brain tumours due to its invasive growth. The effect of glioma treatment is poor because of the presence of the blood-brain barrier and blood tumour barrier and insufficient drug targeting. DNA tetrahedrons (TDN) show great potential for drug delivery and may be a novel therapeutic strategy for glioma. In this study, we used TDN to deliver doxorubicin (DOX) for the glioma therapy. Gint4.T, an aptamer that could recognize platelet-derived growth factor receptor β on tumour cell, was used to modify TDN (Apt-TDN) for targeted drug delivery. The TDN were self-assembled by one-step synthesis, which showed small size (10 nm) and negative charge. Fetal bovine serum test showed its stability as a drug delivery vehicle. Apt-TDN could be effectively taken up by U87MG cells. Compared with DOX and DOX@TDN (TDN loaded with DOX), the DOX@Apt-TDN (Gint4.T-modified TDN loaded with DOX) showed more early apoptosis rate, higher cell cycle arrest, and greater cytotoxicity towards U87MG cells. In conclusion, our findings indicated that DOX@Apt-TDN provides a novel therapy with promising clinical application for gliomas patients.

Tetrahedral DNA nanostructures as drug delivery and bioimaging platforms in cancer therapy

Structural DNA nanotechnology enables DNA to be used as nanomaterials for novel nanostructure construction with unprecedented functionalities. Artificial DNA nanostructures can be designed and generated with precisely controlled features, resulting in its utility in bionanotechnological and biomedical applications. A tetrahedral DNA nanostructure (TDN), the most popular DNA nanostructure, with high stability and simple synthesis procedure, is a promising candidate as nanocarriers in drug delivery and bioimaging platforms, particularly in precision medicine as well as diagnosis for cancer therapy. Recent evidence collectively indicated that TDN successfully enhanced cancer therapeutic efficiency both in vitro and in vivo. Here, we summarize the development of TDN and highlight various aspects of TDN applications in cancer therapy based on previous reports, including anticancer drug loading, photodynamic therapy, therapeutic oligonucleotides, bioimaging platforms, and other molecules and discuss a perspective in opportunities and challenges for future TDN‐based nanomedicine.

Penetrating the Blood-Brain Barrier by Self-Assembled 3D DNA Nanocages as Drug Delivery Vehicles for Brain Cancer Therapy

The development of biocompatible drug delivery vehicles for cancer therapy in the brain remains a big challenge. In this study, we designed self-assembled DNA nanocages functionalized with or without blood-brain barrier (BBB)-targeting ligands, d and we investigated their penetration across the BBB. Our DNA nanocages were not cytotoxic and they were substantially taken up in brain capillary endothelial cells and Uppsala 87 malignant glioma (U-87 MG) cells. We found that ligand modification is not essential for this DNA system as the ligand-free DNA nanocages (LF-NCs) could still cross the BBB by endocytosis inin vitro and in vivo models. Our spherical DNA nanocages were more permeable across the BBB compared with tubular DNA nanotubes. Remarkably, in vivo studies revealed that DNA nanocages could carry anticancer drugs across the BBB and inhibit the tumor growth in a U-87 MG xenograft mouse model. This is the first example showing the potential of DNA nanocages as innovative delivery vehicles to the brain for cancer therapy. Unlike other delivery systems, our work suggest that a DNA nanocage-based platform provides a safe and cost-effective tool for targeted delivery to the brain and therapy for brain tumors.

Chinese medicine Tongxinluo capsule protects against blood-brain barrier disruption after ischemic stroke by inhibiting the low-density lipoprotein receptor-related protein 1 pathway in mice

BACKGROUND

Chinese medicine Tongxinluo capsule (TXL) has been extensively used to treat ischemic stroke in China, and one of its mechanisms is to protect against blood brain barrier (BBB) disruption after stroke. However, the underlying protective mechanisms are not fully illuminated. It is reported that the low-density lipoprotein receptor-related protein 1 (LRP-1) is involved in BBB disruption after brain ischemia. In this study, we explored whether TXL could downregulate LRP-1 expression and subsequently protect against BBB disruption after stroke using permanent middle cerebral artery occlusion (pMCAO) in mice.

METHODS

The animal model of ischemic stroke was induced by pMCAO in male adult C57BL/6J mice. The mice were orally administered TXL (3.0 g/kg) at 1, 3 and 21 h after pMCAO. Meanwhile, the LRP-1 antagonist receptor associated protein (RAP) was intracerebroventricularly injected at 1 and 21 h after stroke. We measured the following parameters at 6 and 24 h: LRP-1 protein level, BBB leakage, and the expression of tight junction (TJ) proteins including occludin, claudin-5 and zonula occludens-1 (ZO-1).

RESULTS

Our results showed that TXL downregulated LRP-1 level, upregulated these TJ proteins level, and reduced BBB leakage in peri-infarct regions after pMCAO. Further study found that the inhibitor RAP played the same role as did TXL in upregulating these TJ proteins level and reducing BBB leakage after stroke.

CONCLUSION

Our study demonstrates that TXL protects against BBB disruption after stroke via inhibiting the LRP-1 pathway.

Nanodelivery Systems for Topical Management of Skin Disorders

Topical drug delivery has inherent advantages over other administration routes. However, the existence of stratum corneum limits the diffusion to small and lipophilic drugs. Fortunately, the advancement of nanotechnology brings along opportunities to address this challenge. Taking the unique features in size and surface chemistry, nanocarriers such as liposomes, polymeric nanoparticles, gold nanoparticles, and framework nucleic acids have been used to bring drugs across the skin barrier to epidermis and dermis layers. This article reviews the development of these formulations and focuses on their applications in the treatment of skin disorders such as acne, skin inflammation, skin infection, and wound healing. Existing hurdles and further developments are also discussed.

Interactions Between Tumor Biology and Targeted Nanoplatforms for Imaging Applications

Although considerable efforts have been conducted to diagnose, improve, and treat cancer in the past few decades, existing therapeutic options are insufficient, as mortality and morbidity rates remain high. Perhaps the best hope for substantial improvement lies in early detection. Recent advances in nanotechnology are expected to increase the current understanding of tumor biology, and will allow nanomaterials to be used for targeting and imaging both in vitro and in vivo experimental models. Owing to their intrinsic physicochemical characteristics, nanostructures (NSs) are valuable tools that have received much attention in nanoimaging. Consequently, rationally designed NSs have been successfully employed in cancer imaging for targeting cancer-specific or cancer-associated molecules and pathways. This review categorizes imaging and targeting approaches according to cancer type, and also highlights some new safe approaches involving membrane-coated nanoparticles, tumor cell-derived extracellular vesicles, circulating tumor cells, cell-free DNAs, and cancer stem cells in the hope of developing more precise targeting and multifunctional nanotechnology-based imaging probes in the future.

The Application of Tetrahedral Framework Nucleic Acids as a Drug Carrier in Biomedicine Fields

In recent years, tetrahedral Framework Nucleic Acids(tFNAs) have become a hot topic in the field of DNA nanostructures because of their stable structures, nanoscale size, superior mechanical properties and convenient synthesis with high yield. tFNAs are considered promising drug delivery carriers because they can pass through the cellular membrane without any help and they have a good biocompatibility and biodegradability. Besides, they have rich modification sites, they can be modified by kinds of functional groups. The functionalization molecules can be modified on the vertexes, embedded between the double-stranded DNA of the tetrahedron edges, hanged on the edges, or encapsulated in the cage-like structure of the tetrahedron. The structure of tetrahedron can also be intelligently controlled through smart design, such as integrating DNA hairpin loop structure onto the edges. Nowadays, DNA tetrahedron will have a broader development prospect in the application of drug transport carriers and intelligent drug carriers. Therefore, DNA material is a new carrier material with great advantages and has a very broad application prospect in the construction of an intelligent drug transport system.