DNA Nanostructures for Targeted Antimicrobial Delivery

Lipidated DNA Nanostructures Target and Rupture Bacterial Membranes

Chemistry has the power to endow supramolecular nanostructures with new biomedically relevant functions. Here it is reported that DNA nanostructures modified with cholesterol tags disrupt bacterial membranes to cause microbial cell death. The lipidated DNA nanostructures bind more readily to cholesterol-free bacterial membranes than to cholesterol-rich, eukaryotic membranes. These highly negatively charged, lipidated DNA nanostructures cause bacterial cell death by rupturing membranes. Strikingly, killing is mediated by clusters of barrel-shaped nanostructures that adhere to the membrane without the involvement of expected bilayer-puncturing barrels. These DNA nanomaterials may inspire the development of polymeric or small-molecule antibacterial agents that mimic the principles of selective binding and rupturing to help combat antimicrobial resistance.

Tobramycin-mediated self-assembly of DNA nanostructures for targeted treatment of Pseudomonas aeruginosa-infected lung inflammation

Pseudomonas aeruginosa (PA) is one of the most common multidrug-resistant pathogens found in clinics, often manifesting as biofilms. However, due to the emergence of superbugs in hospitals and the overuse of antibiotics, the prevention and treatment of PA infections have become increasingly challenging. Utilizing DNA nanostructures for packaging and delivering antibiotics presents an intervention strategy with significant potential. Nevertheless, construction of functional DNA nanostructures with multiple functionalities and enhanced stability in physiological settings remains challenging. In this study, the authors propose a magnesium-free assembly method that utilizes tobramycin (Tob) as a mediator to assemble DNA nanostructures, allowing for the functionalization of DNA nanostructures by combining DNA and antibiotics. Additionally, our study incorporates maleimide-modified DNA into the nanostructures to act as a targeting moiety specifically directed towards the pili of PA. The targeting ability of the constructed functional DNA nanostructure significantly improves the local concentration of Tob, thereby reducing the side effects of antibiotics. Our results demonstrate the successful construction of a maleimide-decorated Tob/DNA nanotube (NTTob-Mal) for the treatment of PA-infected lung inflammation. The stability and biocompatibility of NTTob-Mal are confirmed, highlighting its potential for clinical applications. Furthermore, its specificity in recognizing and adhering to PA has been validated. In vitro experiments have shown its efficacy in inhibiting PA biofilm formation, and in a murine model, NTTob-Mal has exhibited significant therapeutic effectiveness against PA-induced pneumonia. In summary, the proposed antibiotic drug-mediated DNA nanostructure assembly approach holds promise as a novel strategy for targeted treatment of PA infections.

Effect of DNA Origami Nanostructures on Bacterial Growth

DNA origami nanostructures are a powerful tool in biomedicine and can be used to combat drug-resistant bacterial infections. However, the effect of unmodified DNA origami nanostructures on bacteria is yet to be elucidated. With the aim to obtain a better understanding of this phenomenon, the effect of three DNA origami shapes, i.e., DNA origami triangles, six-helix bundles (6HBs), and 24-helix bundles (24HBs), on the growth of Gram-negative Escherichia coli and Gram-positive Bacillus subtilis is investigated. The results reveal that while triangles and 24HBs can be used as a source of nutrients by E. coli and thereby promote population growth, their effect is much smaller than that of genomic single- and double-stranded DNA. However, no effect on E. coli population growth is observed for the 6HBs. On the other hand, B. subtilis does not show any significant changes in population growth when cultured with the different DNA origami shapes or genomic DNA. The detailed effect of DNA origami nanostructures on bacterial growth thus depends on the competence signals and uptake mechanism of each bacterial species, as well as the DNA origami shape. This should be considered in the development of antimicrobial DNA origami nanostructures.

Design and Synthesis of DNA Origami Nanostructures to Control TNF Receptor Activation

Clustering of type II tumor necrosis factor (TNF) receptors (TNFRs) is essential for their activation, yet currently available drugs fail to activate signaling. Some strategies aim to cluster TNFR by using multivalent streptavidin or scaffolds based on dextran or graphene. However, these strategies do not allow for control of the valency or spatial organization of the ligands, and consequently control of the TNFR activation is not optimal. DNA origami nanostructures allow nanometer-precise control of the spatial organization of molecules and complexes, with defined spacing, number and valency. Here, we demonstrate the design and characterization of a DNA origami nanostructure that can be decorated with engineered single-chain TNF-related apoptosis-inducing ligand (SC-TRAIL) complexes, which show increased cell killing compared to SC-TRAIL alone on Jurkat cells. The information in this chapter can be used as a basis to decorate DNA origami nanostructures with various proteins, complexes, or other biomolecules.

Rational Engineering of a Multifunctional DNA Assembly for Enhanced Antibacterial Efficacy and Accelerated Wound Healing

DNA-based assemblies hold immense prospects for antibacterial application, yet are constrained by their poor specificity and deficient antibacterial delivery. Herein, the fabrication of a versatile rolling circle amplification (RCA)-sustained DNA assembly is reported, encoding simultaneously with multivalent aptamers and tandem antibacterial agents, for target-specific and efficient antibacterial application. In the compact RCA-sustained antibacterial platform, the facilely organized multivalent aptamers guarantee the target bacteria-specific delivery of sufficient antibacterial agents which is assembled through DNA-stabilizing silver nanostructures. It is shown that the biocompatible DNA system could enhance bacteria elimination and simultaneously facilitate wound healing in vivo. By virtue of the programmable RCA assembly, the present RCA-sustained system provides a highly modular and scalable approach to design versatile multifunctional therapeutic systems.

Multiple Natural Polymers in Drug and Gene Delivery Systems

Natural polymers are organic compounds produced by living organisms. In nature, they exist in three main forms, including proteins, polysaccharides, and nucleic acids. In recent years, with the continuous research on drug and gene delivery systems, scholars have found that natural polymers have promising applications in drug and gene delivery systems due to their excellent properties such as biocompatibility, biodegradability, low immunogenicity, and easy modification. However, since the structure, physicochemical properties, pharmacological properties and biological characteristics of biopolymer molecules have not yet been entirely understood, further studies are required before large-scale clinical application. This review focuses on recent advances in the representative natural polymers such as proteins (albumin, collagen, elastin), polysaccharides (chitosan, alginate, cellulose) and nucleic acids. We introduce the characteristics of various types of natural polymers, and further outline the characterization methods and delivery forms of these natural polymers. Finally, we discuss possible challenges for natural polymers in subsequent experimental studies and clinical applications. It provides an important strategy for the clinical application of natural polymers in drug and gene delivery systems.

Progress in Programmable DNA-Aided Self-Assembly of the Master Frame of a Drug Delivery System

Every year cancer causes approximately 10 million deaths globally. Researchers have developed numerous targeted drug delivery systems (DDSs) with nanoparticles, polymers, and liposomes, but these synthetic materials have poor degradability and low biocompatibility. Because DNA nanostructures have good degradability and high biocompatibility, extensive studies have been performed to construct DDSs with DNA nanostructures as the molecular-layer master frame (MF) assembled via programmable DNA-aided self-assembly for targeted drug release. To learn the progressing trend of self-assembly techniques and keep pace with their recent rapid advancements, it is crucial to provide an overview of their past and recent progress. In this review article, we first present the techniques to assemble the MF of a DDS with solely DNA strands; to assemble MFs with one or more additional type of construction materials, e.g., polymers (including RNA and protein), inorganic nanoparticle, or metal ions, in addition to DNA strands; and to assemble the more complex DNA nanocomplexes. It is observed that both the techniques used and the MFs constructed have become increasingly complex and that the DDS constructed has an increasing number of advanced functions. From our focused review, we anticipate that DDSs with the MF of multiple building materials and DNA nanocomplexes will attract an increasing number of researchers' interests. On the basis of knowledge about materials and functional components (e.g., targeting aptamers/peptides/antibodies and stimuli for drug release) obtained from previously performed studies, researchers can combine more materials with DNA strands to assemble more powerful MFs and incorporate more components to endow DDSs with improved or additional properties/functions, thereby subsequently contributing to cancer prevention.

A DNA Origami-based Bactericide for Efficient Healing of Infected Wounds

Bacteria infection is a significant obstacle in the clinical treatment of exposed wounds facing widespread pathogens. Herein, we report a DNA origami-based bactericide for efficient anti-infection therapy of infected wounds in vivo. In our design, abundant DNAzymes (G4/hemin) can be precisely organized on the DNA origami for controllable generation of reactive oxygen species (ROS) to break bacterial membranes. After the destruction of the membrane, broad-spectrum antibiotic levofloxacin (LEV, loaded in the DNA origami through interaction with DNA duplex) can be easily delivered into the bacteria for successful sterilization. With the incorporation of DNA aptamer targeting bacterial peptidoglycan, the DNA origami-based bactericide can achieve targeted and combined antibacterial therapy for efficiently promoting the healing of infected wounds. This tailored DNA origami-based nanoplatform provides a new strategy for the treatment of infectious diseases in vivo.

Effectors of the Type VI Secretion System Have the Potential to Be Modified into Antimicrobial Peptides

The use of antibiotics has led to the emergence of multidrug-resistant (MDR) bacteria, and there is an urgent need to find alternative treatments to alleviate this pressure. The type VI secretion system (T6SS) is a protein delivery system present in bacterial cells that secretes effectors that participate in bacterial virulence. Given the potential for the transformation of these effectors into antimicrobial peptides (AMPs), we designed T6SS effectors into AMPs that have a membrane-disrupting effect. These effectors kill bacteria by altering the membrane potential and increasing the intracellular reactive oxygen species (ROS) content. Moreover, AMPs also have a significant therapeutic effect both in vivo and in vitro. This finding suggests that it is possible to modify bacterial components of bacteria themselves to create compounds that fight bacteria. IMPORTANCE This study first identified and modified the T6SS effector into positively charged alpha-helical peptides. These peptides have good antibacterial and bactericidal effects on G+ bacteria and G- bacteria. This study broadens the source of AMPs and makes T6SS effectors more useful.

Controlled E. coli Aggregation Mediated by DNA and XNA Hybridization

Chemical cell surface modification is a fast-growing field of research, due to its enormous potential in tissue engineering, cell-based immunotherapy, and regenerative medicine. However, engineering of bacterial tissues by chemical cell surface modification has been vastly underexplored and the identification of suitable molecular handles is in dire need. We present here, an orthogonal nucleic acid-protein conjugation strategy to promote artificial bacterial aggregation. This system gathers the high selectivity and stability of linkage to a protein Tag expressed at the cell surface and the modularity and reversibility of aggregation due to oligonucleotide hybridization. For the first time, XNA (xeno nucleic acids in the form of 1,5-anhydrohexitol nucleic acids) were immobilized via covalent, SNAP-tag-mediated interactions on cell surfaces to induce bacterial aggregation.

Synthetic engineered bacteria for cancer therapy

INTRODUCTION

Cancer mortality worldwide highlights the urgency for advanced therapeutic methods to fill the gaps in conventional cancer therapies. Bacteriotherapy is showing great potential in tumor regression due to the motility and colonization tendencies of bacteria. However, the complicated in vivo environment and tumor pathogenesis hamper the therapeutic outcomes. Synthetic engineering methods endow bacteria with flexible abilities both at the extracellular and intracellular levels to meet treatment requirements. In this review, we introduce synthetic engineering methods for bacterial modifications. We highlight the recent progress in engineered bacteria and explore how these synthetic methods endow bacteria with superior abilities in cancer therapy. The current clinical translations are further discussed. Overall, this review may shed light on the advancement of engineered bacteria for cancer therapy.

AREAS COVERED

Recent progress in synthetic methods for bacterial engineering and specific examples of their applications in cancer therapy are discussed in this review.

EXPERT OPINION

Bacteriotherapy bridges the gaps of conventional cancer therapies through the natural motility and colonization tendency of bacteria, as well as their synthetic engineering. Nevertheless, to fulfill the bacteriotherapy potential and move into clinical trials, more research focusing on its safety concerns should be conducted.

Self-assembly of DNA origami for nanofabrication, biosensing, drug delivery, and computational storage

Since the pioneering work of immobile DNA Holliday junction by Ned Seeman in the early 1980s, the past few decades have witnessed the development of DNA nanotechnology. In particular, DNA origami has pushed the field of DNA nanotechnology to a new level. It obeys the strict Watson-Crick base pairing principle to create intricate structures with nanoscale accuracy, which greatly enriches the complexity, dimension, and functionality of DNA nanostructures. Benefiting from its high programmability and addressability, DNA origami has emerged as versatile nanomachines for transportation, sensing, and computing. This review will briefly summarize the recent progress of DNA origami, two-dimensional pattern, and three-dimensional assembly based on DNA origami, followed by introduction of its application in nanofabrication, biosensing, drug delivery, and computational storage. The prospects and challenges of assembly and application of DNA origami are also discussed.

May carriers at nanoscale improve the Endodontic's future?

Nanocarriers (NCs) are dynamic nanovehicles used to transport bioactive derivatives like therapeutical formulations, drugs and/or dyes. The current review assists in understanding the mechanism of action of several recent developed NCs with antimicrobial purposes. Here, nine NCs varieties are portrayed with focus on nineteen approaches that are fulfil described based on outcomes obtained from in vitro antimicrobial assays. All approaches have previously been verified and we underline the biochemical challenges of all NCs, expecting that the present data may encourage the application of NCs in endodontic antimicrobial basic research. Methodological limitations and the evident base gaps made not possible to draw a definite conclusion about the best NCs for achieving efficient antimicrobial outcomes in endodontic studies. Due to the lack of pre-clinical trials and the scarce number of clinical trials in this emergent area, there is still much room for improvement on several fronts.

Recent advances in targeted antibacterial therapy basing on nanomaterials

Bacterial infection has become one of the leading causes of death worldwide, particularly in low-income countries. Despite the fact that antibiotics have provided successful management in bacterial infections, the long-term overconsumption and abuse of antibiotics has contributed to the emergence of multidrug resistant bacteria. To address this challenge, nanomaterials with intrinsic antibacterial properties or that serve as drug carriers have been substantially developed as an alternative to fight against bacterial infection. Systematically and deeply understanding the antibacterial mechanisms of nanomaterials is extremely important for designing new therapeutics. Recently, nanomaterials-mediated targeted bacteria depletion in either a passive or active manner is one of the most promising approaches for antibacterial treatment by increasing local concentration around bacterial cells to enhance inhibitory activity and reduce side effects. Passive targeting approach is widely explored by searching nanomaterial-based alternatives to antibiotics, while active targeting strategy relies on biomimetic or biomolecular surface feature that can selectively recognize targeted bacteria. In this review article, we summarize the recent developments in the field of targeted antibacterial therapy based on nanomaterials, which will promote more innovative thinking focusing on the treatment of multidrug-resistant bacteria.

An Infectious Virus-like Particle Built on a Programmable Icosahedral DNA Framework

Viral genomes can be compressed into a near-spherical nanochamber to form infectious particles. In order to mimic the virus morphology and packaging behavior, we invented a programmable icosahedral DNA nanoframe with enhanced rigidity and encapsulated the phiX174 bacteriophage genome. The packaging efficiency could be modulated through specific anchoring strands adjustment, and the trapped phage genome remained accessible for enzymatic operations. Moreover, the packed complex could infect Escherichia coli (E. coli) cells through bacterial uptake to produce plaques. This rigid icosahedral DNA architecture demonstrated a versatile platform to develop virus mimetic particles for convenient functional nucleic acid entrapment, manipulation and delivery.

Vivern-A Virtual Environment for Multiscale Visualization and Modeling of DNA Nanostructures

DNA nanostructures offer promising applications, particularly in the biomedical domain, as they can be used for targeted drug delivery, construction of nanorobots, or as a basis for molecular motors. One of the most prominent techniques for assembling these structures is DNA origami. Nowadays, desktop applications are used for the in silico design of such structures. However, as such structures are often spatially complex, their assembly and analysis are complicated. Since virtual reality (VR) was proven to be advantageous for such spatial-related tasks and there are no existing VR solutions focused on this domain, we propose Vivern, a VR application that allows domain experts to design and visually examine DNA origami nanostructures. Our approach presents different abstracted visual representations of the nanostructures, various color schemes, and an ability to place several DNA nanostructures and proteins in one environment, thus allowing for the detailed analysis of complex assemblies. We also present two novel examination tools, the Magic Scale Lens and the DNA Untwister, that allow the experts to visually embed different representations into local regions to preserve the context and support detailed investigation. To showcase the capabilities of our solution, prototypes of novel nanodevices conceptualized by our collaborating experts, such as DNA-protein hybrid structures and DNA origami superstructures, are presented. Finally, the results of two rounds of evaluations are summarized. They demonstrate the advantages of our solution, especially for scenarios where current desktop tools are very limited, while also presenting possible future research directions.

Direct visualization of the drug loading of single DNA origami nanostructures by AFM-IR nanospectroscopy

The efficient loading of DNA nanostructures with intercalating or groove-binding drugs is an important prerequisite for various applications in drug delivery. However, unambiguous verification and quantification of successful drug loading is often rather challenging. In this work, AFM-IR nanospectroscopy is thus employed to directly visualize the loading of DNA origami nanostructures with the photosensitizer methylene blue (MB). Single MB-loaded DNA origami nanostructures can be clearly resolved in high-resolution infrared (IR) maps and the occurrence of MB-specific IR absorption correlates well with the topographic signals of the DNA origami nanostructures. The intensity of the recorded MB absorption bands furthermore scales with the MB concentration used for MB loading. By comparing single- and multilayer DNA origami nanostructures, it is also shown that the IR signal intensity of the loaded MB increases with the thickness of the DNA origami nanostructures. This indicates that also DNA double helices located in the core of bulky 3D DNA origami nanostructures are accessible for MB loading. AFM-IR nanospectroscopy thus has the potential to become an invaluable tool for quantifying drug loading of DNA origami nanostructures and optimizing drug loading protocols.

DNA origami in the quest for membrane piercing

The tool kit for label-free single-molecule sensing, nucleic acid sequencing (DNA, RNA and protein) and other biotechnological applications has been significantly broadened due to the wide range of available nanopore-based technologies. Currently, various sources of nanopores, including biological, fabricated solid-state, hybrid and recently de novo chemically synthesized ion-like channels have put in use for rapid single-molecule sensing of biomolecules and other diagnostic applications. At length scales of hundreds of nanometers, DNA nanotechnology, particularly DNA origami-based devices, enables the assembly of complex and dynamic 3-dimensional nanostructures, including nanopores with precise control over the size/shape. DNA origami technology has enabled to construct nanopores by DNA alone or hybrid architects with solid-state nanopore devices or nanocapillaries. In this review, we briefly discuss the nanopore technique that uses DNA nanotechnology to construct such individual pores in lipid-based systems or coupled with other solid-state devices, nanocapillaries for enhanced biosensing function. We summarize various DNA-based design nanopores and explore the sensing properties of such DNA channels. Apart from DNA origami channels we also pointed the design principles of RNA nanopores for peptide sensing applications.

Aptamers for Viral Detection and Inhibition

Recent times have experienced more than ever the impact of viral infections in humans. Viral infections are known to cause diseases not only in humans but also in plants and animals. Here, we have compiled the literature review of aptamers selected and used for detection and inhibition of viral infections in all three categories: humans, animals, and plants. This review gives an in-depth introduction to aptamers, different types of aptamer selection (SELEX) methodologies, the benefits of using aptamers over commonly used antibody-based strategies, and the structural and functional mechanism of aptasensors for viral detection and therapy. The review is organized based on the different characterization and read-out tools used to detect virus-aptasensor interactions with a detailed index of existing virus-targeting aptamers. Along with addressing recent developments, we also discuss a way forward with aptamers for DNA nanotechnology-based detection and treatment of viral diseases. Overall, this review will serve as a comprehensive resource for aptamer-based strategies in viral diagnostics and treatment.

Advances in the Sensing and Treatment of Wound Biofilms

Wound biofilms represent a particularly challenging problem in modern medicine. They are increasingly antibiotic resistant and can prevent the healing of chronic wounds. However, current treatment and diagnostic options are hampered by the complexity of the biofilm environment. In this review, we present new chemical avenues in biofilm sensors and new materials to treat wound biofilms, offering promise for better detection, chemical specificity, and biocompatibility. We briefly discuss existing methods for biofilm detection and focus on novel, sensor-based approaches that show promise for early, accurate detection of biofilm formation on wound sites and that can be translated to point-of-care settings. We then discuss technologies inspired by new materials for efficient biofilm eradication. We focus on ultrasound-induced microbubbles and nanomaterials that can both penetrate the biofilm and simultaneously carry active antimicrobials and discuss the benefits of those approaches in comparison to conventional methods.

Multivalent Aptamer Approach: Designs, Strategies, and Applications

Aptamers are short and single-stranded DNA or RNA molecules with highly programmable structures that give them the ability to interact specifically with a large variety of targets, including proteins, cells, and small molecules. Multivalent aptamers refer to molecular constructs that combine two or more identical or different types of aptamers. Multivalency increases the avidity of aptamers, a particularly advantageous feature that allows for significantly increased binding affinities in comparison with aptamer monomers. Another advantage of multivalency is increased aptamer stabilities that confer improved performances under physiological conditions for various applications in clinical settings. The current study aims to review the most recent developments in multivalent aptamer research. The review will first discuss structures of multivalent aptamers. This is followed by detailed discussions on design strategies of multivalent aptamer approaches. Finally, recent developments of the multivalent aptamer approach in biosensing and biomedical applications are highlighted.

Engineering bacterial surface interactions using DNA as a programmable material

The diverse surface interactions and functions of a bacterium play an important role in cell signaling, host infection, and colony formation. To understand and synthetically control the biological functions of individual cells as well as the whole community, there is growing attention on the development of chemical and biological tools that can integrate artificial functional motifs onto the bacterial surface to replace the native interactions, enabling a variety of applications in biosynthesis, environmental protection, and human health. Among all these functional motifs, DNA emerges as a powerful tool that can precisely control bacterial interactions at the bio-interface due to its programmability and biorecognition properties. Compared with conventional chemical and genetic approaches, the sequence-specific Watson-Crick interaction enables almost unlimited programmability in DNA nanostructures, realizing one base-pair spatial control and bio-responsive properties. This highlight aims to provide an overview on this emerging research topic of DNA-engineered bacterial interactions from the aspect of synthetic chemists. We start with the introduction of native bacterial surface ligands and established synthetic approaches to install artificial ligands, including direct modification, metabolic engineering, and genetic engineering. A brief overview of DNA nanotechnology, reported DNA-bacteria conjugation chemistries, and several examples of DNA-engineered bacteria are included in this highlight. The future perspectives and challenges in this field are also discussed, including the development of dynamic bacterial surface chemistry, assembly of programmable multicellular community, and realization of bacteria-based theranostic agents and synthetic microbiota as long-term goals.

DNA origami-based protein manipulation systems: From function regulation to biological application

Proteins directly participate in tremendous physiological processes and mediate a variety of cellular functions. However, precise manipulation of proteins with predefined relative position and stoichiometry for understanding protein-protein interactions and guiding cellular behaviors are still challenging. With superior programmability of DNA molecules, DNA origami technology is able to construct arbitrary nanostructures that can accurately control the arrangement of proteins with various functionalities to solve these problems. Herein, starting from the classification of DNA origami nanostructures and the category of assembled proteins, we summarize the existing DNA origami-based protein manipulation systems (PMSs), review the advances on the regulation of their functions, and discuss their applications in cellular behavior modulation and disease therapy. Moreover, the limitations and potential directions of DNA origami-based PMSs are also presented, which may offer guidance for rational construction and ingenious application.

Biofilm Responsive Zwitterionic Antimicrobial Nanoparticles to Treat Cutaneous Infection

To avert the poor bioavailability of antibiotics during S. aureus biofilm infections, a series of zwitterionic nanoparticles containing nucleic acid nanostructures were fabricated for the delivery of vancomycin. The nanoparticles were prepared with three main lipids: (i) neutral (soy phosphatidylcholine; P), (ii) positively charged ionizable (1,2-dioleyloxy-3-dimethylaminopropane; D), and (iii) anionic (1,2-dipalmitoyl-sn-glycero-3-phospho((ethyl-1′,2′,3′-triazole) triethylene glycolmannose; M) or (cholesteryl hemisuccinate; C) lipids. The ratio of the anionic lipid was tuned between 0 and 10 mol %, and its impact on surface charge, size, stability, toxicity, and biofilm sensitivity was evaluated. Under biofilm mimicking conditions, the enzyme degradability (via dynamic light scattering (DLS)), antitoxin (via DLS and spectrophotometry), and antibiotic release profile was assessed. Additionally, biofilm penetration, prevention (in vitro), and eradication (ex vivo) of the vancomycin loaded formulation was investigated. Compared with the unmodified nanoparticles which exhibited the smallest size (188 nm), all three surface modified formulations showed significantly larger sizes (i.e., 222–277 nm). Under simulations of biofilm pH conditions, the mannose modified nanoparticle (PDM 90/5/5) displayed ideal charge reversal from a neutral (+1.69 ± 1.83 mV) to a cationic surface potential (+17.18 ± 2.16 mV) to improve bacteria binding and biofilm penetration. In the presence of relevant bacterial enzymes, the carrier rapidly released the DNA nanoparticles to function as an antitoxin against α-hemolysin. Controlled release of vancomycin prevented biofilm attachment and significantly reduced early stage biofilm formations within 24 h. Enhanced biocompatibility and significant ex vivo potency of the PDM 90/5/5 formulation was also observed. Taken together, these results emphasize the benefit of these nanocarriers as potential therapies against biofilm infections and fills the gap for multifunctional nanocarriers that prevent biofilm infections.

Self-Assembling Nucleic Acid Nanostructures Functionalized with Aptamers

Researchers have worked for many decades to master the rules of biomolecular design that would allow artificial biopolymer complexes to self-assemble and function similarly to the diverse biochemical constructs displayed in natural biological systems. The rules of nucleic acid assembly (dominated by Watson-Crick base-pairing) have been less difficult to understand and manipulate than the more complicated rules of protein folding. Therefore, nucleic acid nanotechnology has advanced more quickly than de novo protein design, and recent years have seen amazing progress in DNA and RNA design. By combining structural motifs with aptamers that act as affinity handles and add powerful molecular recognition capabilities, nucleic acid-based self-assemblies represent a diverse toolbox for use by bioengineers to create molecules with potentially revolutionary biological activities. In this review, we focus on the development of self-assembling nucleic acid nanostructures that are functionalized with nucleic acid aptamers and their great potential in wide ranging application areas.

Advances in the Sensing and Treatment of Wound Biofilms

Wound biofilms represent a particularly challenging problem in modern medicine. They are increasingly antibiotic resistant and can prevent the healing of chronic wounds. However, current treatment and diagnostic options are hampered by the complexity of the biofilm environment. In this review, we present new chemical avenues in biofilm sensors and new materials to treat wound biofilms, offering promise for better detection, chemical specificity, and biocompatibility. We briefly discuss existing methods for biofilm detection and focus on novel, sensor‐based approaches that show promise for early, accurate detection of biofilm formation on wound sites and that can be translated to point‐of‐care settings. We then discuss technologies inspired by new materials for efficient biofilm eradication. We focus on ultrasound‐induced microbubbles and nanomaterials that can both penetrate the biofilm and simultaneously carry active antimicrobials and discuss the benefits of those approaches in comparison to conventional methods.

DNA Nanodevice as a Co-delivery Vehicle of Antisense Oligonucleotide and Silver Ions for Selective Inhibition of Bacteria Growth

DNA nanostructures possess unique programmability and addressability and exhibit a wide variety of potential applications. Recently, they demonstrated their ability to be ideal carriers of antibacterial drugs. In this study, the first use of a DNA six-helix bundle (6HB) nanostructure to co-deliver antisense oligonucleotide (ASO) and silver ions is reported. Although 6HB with Ag⁺ shows excellent antibacterial effect against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, 6HB with ASO selectively inhibits S. aureus. Furthermore, 6HB with both Ag⁺ and ASO exhibits enhanced antibacterial efficacy on S. aureus, probably through two sequential activities. Specifically, Ag⁺-modified 6HB greatly delays bacterial growth by destroying its cell walls, whereas 6HB conjugated with ASO targeting the ftsZ gene of S. aureus effectively inhibits its growth in the logarithmic growth phase by inhibiting the expression of the ftsZ gene. Moreover, this synergistic antibacterial treatment shows excellent biosafety with human normal liver cell L02. This co-delivery system by DNA nanostructures provides a promising platform for antibacterial therapeutics.

Nano-vehicles give new lease of life to existing antimicrobials

Antibiotic resistance has become one of the greatest challenges for modern medicine, and new approaches for the treatment of bacterial infections are urgently needed to avoid widespread vulnerability again to infections that have so far been easily treatable with existing drugs. Among the many approaches investigated to overcome this challenge is the use of engineered nanostructures for the precise and targeted delivery of existing antimicrobial agents in a fashion that will potentiate their effect. This idea leans on lessons learned from pioneering research in cancer, where the targeted delivery of anti-cancer drugs to mammalian cells has been a topic for some time. In particular, new research has demonstrated that nanomaterials can be functionalised with active antimicrobials and, in some cases, with targeting molecules that potentiate the efficiency of the antimicrobials. In this mini-review, we summarise results that demonstrate the potential for nanoparticles, dendrimers and DNA nanostructures for use in antimicrobial delivery. We consider material aspects of the delivery vehicles and ways in which they can be functionalised with antibiotics and antimicrobial peptides, and we review evidence for their efficacy to kill bacteria both in vitro and in vivo. We also discuss the advantages and limitations of these materials and highlight the benefits of DNA nanostructures specifically for their versatile potential in the present context.

Targeted Therapeutic Strategies in the Battle Against Pathogenic Bacteria

The emergence and rapid spread of antibiotic resistance in pathogenic bacteria constitute a global threat for public health. Despite ongoing efforts to confront this crisis, the pace of finding new potent antimicrobials is far slower than the evolution of drug resistance. The abuse of broad-spectrum antibiotics not only accelerates the formation of resistance but also imposes a burden on the intestinal microbiota, which acts a critical role in human homeostasis. As such, innovative therapeutic strategies with precision are pressingly warranted and highly anticipated. Recently, target therapies have achieved some breakthroughs by the aid of modern technology. In this review, we provide an insightful illustration of current and future medical targeted strategies, including narrow-spectrum agents, engineered probiotics, nanotechnology, phage therapy, and CRISPR-Cas9 technology. We discuss the recent advances and potential hurdles of these strategies. Meanwhile, the possibilities to mitigate the spread of resistance in these approaches are also mentioned. Altogether, a better understanding of the advantages, disadvantages, and mechanisms of action of these targeted therapies will be conducive to broadening our horizons and optimizing the existing antibacterial approaches.

Single-molecule DNA origami aptasensors for real-time biomarker detection

Here we report the use of DNA nanostructures as platforms to monitor the inherent conformational changes of aptamers upon analyte binding, with single-molecule resolution and real-time capability. An aptasensor designed to sense cortisol was found to suffer from instability in solution, but this was reconciled via a rational design of a single-molecule sensing platform. In this regard, DNA origami was employed to immobilise individual aptasensors on a glass surface and to ensure adequate interaction with their environment, for single-molecule analysis. The strategy presented here can be applied to any aptamer obtained by the destabilisation of a duplex in a SELEX process, and hence employed in the rational design of single-molecule biosensors.

Montmorillonite nanosheets with enhanced photodynamic performance for synergistic bacterial ablation

Montmorillonite (MMT), as a naturally sourced and FDA-approved biomaterial, has attracted considerable attention due to its extensive application in biomedical areas, such as intestinal ailments, drug delivery, and additive manufacturing. In this work, two-dimensional montmorillonite (2D-MMT) ultrathin nanosheets were successfully prepared from sodium montmorillonite (Na-MMT) by utilizing a freeze-drying assisted method. Possessing a large specific surface area and increased number of exposed hydroxyl groups, 2D-MMT nanosheets exhibited better antibacterial ability than the original Na-MMT. More strikingly, we found that both 2D-MMT nanosheets and Na-MMT could generate reactive oxygen species (ROS) upon visible light illumination, which could promote their antibacterial efficiency. As a result, 2D-MMT nanosheets showed efficient antibacterial performance in the presence of light towards Escherichia coli with a simultaneous enhancement of surface adsorption and photodynamic ablation. What's more, a possible mechanism for ROS generation by MMT upon light illumination was first proposed in this work. The combination of the increased physical adsorption capacity and ROS generation ability of 2D-MMT nanosheets would help inspire the development of MMT as a promising antimicrobial candidate in the future.

DNA Nanostructures in the Fight Against Infectious Diseases

Throughout history, humanity has been threatened by countless epidemic and pandemic outbreaks of infectious diseases, from the Justinianic Plague to the Spanish flu to COVID-19. While numerous antimicrobial and antiviral drugs have been developed over the last 200 years to face these threats, the globalized and highly connected world of the 21st century demands for an ever-increasing efficiency in the detection and treatment of infectious diseases. Consequently, the rapidly evolving field of nanomedicine has taken up the challenge and developed a plethora of strategies to fight infectious diseases with the help of various nanomaterials such as noble metal nanoparticles, liposomes, nanogels, and virus capsids. DNA nanotechnology represents a comparatively recent addition to the nanomedicine arsenal, which, over the past decade, has made great progress in the area of cancer diagnostics and therapy. However, the past few years have seen also an increasing number of DNA nanotechnology-related studies that particularly focus on the detection and inhibition of microbial and viral pathogens. Herein, a brief overview of this rather young research field is provided, successful concepts as well as potential challenges are identified, and promising directions for future research are highlighted.

Hierarchical Fabrication of DNA Wireframe Nanoarchitectures for Efficient Cancer Imaging and Targeted Therapy

Though small-molecule drugs play a crucial role in cancer treatment, intrinsic issues such as poor solubility and systematic toxicity have considerably mitigated their anticancer functions and caused unwanted side effects. To achieve satisfying therapeutic efficiency, it is essential to develop innovative targeting systems for precise and efficient delivery of anticancer drugs. In this work, a hierarchical self-assembly strategy was applied to fabricate a core-shell nanoarchitecture composed of a DNA octahedral wireframe and chemodrug-functionalized Sgc8c aptamer. The integrated enhanced permeability and retention effect of the DNA nanostructure and active targeting ability of the Sgc8c aptamer allowed the highly selective chemodrug delivery and in vivo efficient imaging and treatment. The advantage of our multifunctional nanostructure was further highlighted by its impressive serum stability, excellent accumulation ability, deep penetration capability, significantly improved therapeutic efficacy, and favorable biosafety. This study showed promising potential of such a core-shell DNA nanoarchitecture in precise drug loading control, drug delivery, and personal medicine.

Smart Nanocarriers for the Delivery of Nucleic Acid-Based Therapeutics: A Comprehensive Review

Nucleic acid-based therapies are promising therapeutics for the treatment of several systemic disorders, and they offer an exciting opportunity to address emerging biological challenges. The scope of nucleic acid-based therapeutics in the treatment of multiple disease states including cancers has been widened by recent progress in Ribonucleic acids (RNA) biology. However, cascades of systemic and intracellular barriers, including rapid degradation, renal clearance, and poor cellular uptake, hinder the clinical effectiveness of nucleic acid-based therapies. These barriers can be circumvented by utilizing advanced smart nanocarriers that efficiently deliver and release the encapsulated nucleic acids into the target tissues. This review describes the current status of clinical trials on nucleic acid-based therapeutics and highlights representative examples that provide an overview on the current and emerging trends in nucleic acid-based therapies. A better understanding of the design of advanced nanocarriers is essential to promote the translation of therapeutic nucleic acids into a clinical reality.

DNA Nanostructures for Targeted Antimicrobial Delivery

We report the use of DNA origami nanostructures, functionalized with aptamers, as a vehicle for delivering the antibacterial enzyme lysozyme in a specific and efficient manner. We test the system against Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) targets. We use direct stochastic optical reconstruction microscopy (dSTORM) and atomic force microscopy (AFM) to characterize the DNA origami nanostructures and structured illumination microscopy (SIM) to assess the binding of the origami to the bacteria. We show that treatment with lysozyme-functionalized origami slows bacterial growth more effectively than treatment with free lysozyme. Our study introduces DNA origami as a tool in the fight against antibiotic resistance, and our results demonstrate the specificity and efficiency of the nanostructure as a drug delivery vehicle.

Nucleic Acid Hybrids as Advanced Antibacterial Nanocarriers

Conventional antibiotic therapy is often challenged by poor drug penetration/accumulation at infection sites and poses a significant burden to public health. Effective strategies to enhance the therapeutic efficacy of our existing arsenal include the use of nanoparticulate delivery platforms to improve drug targeting and minimize adverse effects. However, these nanocarriers are often challenged by poor loading efficiency, rapid release and inefficient targeting. Nucleic acid hybrid nanocarriers are nucleic acid nanosystems complexed or functionalized with organic or inorganic materials. Despite their immense potential in antimicrobial therapy, they are seldom utilized against pathogenic bacteria. With the emergence of antimicrobial resistance and the associated complex interplay of factors involved in antibiotic resistance, nucleic acid hybrids represent a unique opportunity to deliver antimicrobials against resistant pathogens and to target specific genes that control virulence or resistance. This review provides an unbiased overview on fabricating strategies for nucleic acid hybrids and addresses the challenges of pristine oligonucleotide nanocarriers. We report recent applications to enhance pathogen targeting, binding and control drug release. As multifunctional next-generational antimicrobials, the challenges and prospect of these nanocarriers are included.