Nucleic acid degradation as barrier to gene delivery: a guide to understand and overcome nuclease activity

The role of micro-ribonucleic acid and small interfering-ribonucleic acid in precision nutrition for obesity management

BACKGROUND & AIMS

Precision nutrition aims to tailor dietary interventions based on genetic and molecular profiles. MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) are emerging as critical tools in precision obesity management. miRNAs serve as biomarkers for predicting dietary response and obesity risk, while siRNAs provide a targeted approach to silencing obesity-related genes. This review explores the mechanisms, applications, and potential of integrating miRNA and siRNA in personalized dietary strategies to combat obesity.

METHODS

A comprehensive literature review was conducted using Boolean operations to identify studies on miRNAs, siRNAs, and their roles in precision nutrition. The review focused on molecular mechanisms, clinical applications, challenges, and future directions in integrating miRNA detection and siRNA therapy for obesity management.

RESULTS

miRNAs regulate gene expression related to lipid metabolism, adipogenesis, and insulin sensitivity, with miRNA-33 and miRNA-103/107 being notable examples. siRNAs offer precise gene silencing for targets like SREBP-1c and PPARγ, addressing metabolic pathways resistant to dietary interventions. The synergistic integration of miRNAs as biomarkers and siRNAs as therapeutic tools enhances the personalization and efficacy of obesity management.

CONCLUSIONS

The dual application of miRNAs and siRNAs in precision nutrition represents a transformative approach to obesity management. While challenges such as molecular stability and delivery systems persist, advancements in RNA technology and clinical research promise to revolutionize personalized dietary strategies. Future research should focus on large-scale trials and ethical considerations to ensure equitable and effective implementation.

Toward successful retinal drug delivery after intravitreal injection: Current strategies to overcome the inner limiting membrane

The global prevalence of retinal disorders leading to vision impairment and blindness is rising to significant numbers and is estimated to continuously increase in the coming years. Although many groundbreaking therapies are available in the expanding field of retinal gene and cell therapy, troublesome delivery after intravitreal (IVT) injection is currently complicating their clinical translation. In this regard, the inner limiting membrane (ILM), the basement membrane located between the vitreous and the retina, is recognized as the main obstacle hindering retinal entry. Overcoming this barrier might hence advance a plethora of potent therapeutics currently available but failing to enter the retina. Aware of the importance to address this drug delivery issue, this review will discuss the current proposed methods to tackle the ILM barrier. First, we will provide an overview of ILM characteristics in health and disease after which we will reflect on the relevance of the ILM barrier role for emerging advanced therapeutic strategies. Seeing the significance of ILM removal for those therapeutics, the current proposed surgical, pharmacological and physical strategies to bypass the ILM will furthermore be highlighted to encourage the entire field of retinal drug delivery after IVT injection forward.

Stereochemistry of Phosphorothioate Linkages Impacts the Structure and Binding Affinity of Aptamers and DNAzymes

The introduction of chemical modifications to oligonucleotides has been pivotal to their emergence as effective therapeutic agents. Understanding how these modifications influence the higher-order structure of oligonucleotides is one of the key considerations during the drug development process. Here, we use a G-quadruplex (thrombin-binding aptamer) and stem/loop structure (dehydroepiandrosterone sulfate binding aptamer) as model cases to show for the first time that the stereochemistry of phosphorothioate linkages can affect the stability and function of oligonucleotides that depend on their intramolecular conformation for activity (e.g., aptamers and DNAzymes). Differences up to 15 °C in melting temperature are observed between stereochemical variants of the same sequence. Moreover, using a hemin-DNAzyme assay and small molecule recognizing fluorogenic aptamer, we illustrate that stereochemistry can be used to tune the binding affinity and activity of the oligonucleotides examined in this study toward non-nucleic acid targets. Taken together, these discoveries highlight the potential influence of stereochemistry on the structure and function of other phosphorothioate-containing oligonucleotides, revealing important considerations for future drug design.

Nanotechnology-Enhanced siRNA Delivery: Revolutionizing Cancer Therapy

RNA interference (RNAi) has emerged as a transformative approach for cancer therapy, enabling precise gene silencing through small interfering RNA (siRNA). However, the clinical application of siRNA-based treatments faces challenges such as rapid degradation, inefficient cellular uptake, and immune system clearance. Nanotechnology-enhanced siRNA delivery has revolutionized cancer therapy by addressing these limitations, improving siRNA stability, tumor-specific targeting, and therapeutic efficacy. Recent advancements in nanocarrier engineering have introduced innovative strategies to enhance the safety and precision of siRNA-based therapies, offering new opportunities for personalized medicine. This review highlights three key innovations in nanotechnology-enhanced siRNA delivery: artificial intelligence (AI)-driven nanocarrier design, multifunctional nanoparticles for combined therapeutic strategies, and biomimetic nanocarriers for enhanced biocompatibility. AI-driven nanocarriers utilize machine learning algorithms to optimize nanoparticle properties, improving drug release profiles and minimizing off-target effects. Multifunctional nanoparticles integrate siRNA with chemotherapy, immunotherapy, or photothermal therapy, enabling synergistic treatment approaches that enhance therapeutic outcomes and reduce drug resistance. Biomimetic nanocarriers, including exosome-mimicking systems and cell-membrane-coated nanoparticles, improve circulation time, immune evasion, and targeted tumor delivery. These innovations collectively enhance the precision, efficiency, and safety of siRNA-based cancer therapies. The scope and novelty of these advancements lie in their ability to overcome the primary barriers of siRNA delivery while paving the way for clinically viable solutions. This review provides a comprehensive analysis of the latest developments in nanocarrier fabrication, preclinical and clinical studies, and safety assessments. By integrating AI-driven design, multifunctionality, and biomimicry, nanotechnology-enhanced siRNA delivery holds immense potential for the future of precision cancer therapy.

Investigating the stability of RNA-lipid nanoparticles in biological fluids: Unveiling its crucial role for understanding LNP performance

Lipid nanoparticles (LNPs) are the most established and clinically advanced platform for RNA delivery. While significant efforts have been made to improve RNA delivery efficiency for improved protein production, the interplay between physiological stability, target specificity, and therapeutic efficacy of RNA-LNPs remains largely unexplored. This review highlights the crucial, yet often overlooked, impact of in vivo stability or instability of RNA-LNPs in contact with biological fluids on delivery performance. We discuss the various factors, including lipid composition, particle surface properties and interactions with proteins in physiological conditions, and provide an overview of the current methods for assessing RNA-LNP stability in biological fluids, such as dynamic laser light scattering, liquid chromatography, and fluorescent and radiolabeled techniques. In the final part, we propose strategies for enhancing stability, with a focus on shielding lipids. Therefore, this work highlights the importance of investigating and understanding the balance between stability and instability of LNPs in the biological context to achieve a more meaningful correlation between formulation properties and in vivo performance.

Immune Modulation with Oral DNA/RNA Nanoparticles

The oral delivery of DNA/RNA nanoparticles represents a transformative approach in immunotherapy and vaccine development. These nanoparticles enable targeted immune modulation by delivering genetic material to specific cells in the gut-associated immune system, triggering both mucosal and systemic immune responses. Unlike parenteral administration, the oral route offers a unique immunological environment that supports both tolerance and activation, depending on the formulation design. This review explores the underlying mechanisms of immune modulation by DNA/RNA nanoparticles, their design and delivery strategies, and recent advances in their application. Emphasis is placed on strategies to overcome physiological barriers such as acidic pH, enzymatic degradation, mucus entrapment, and epithelial tight junctions. Special attention is given to the role of gut-associated lymphoid tissue in mediating immune responses and the therapeutic potential of these systems in oral vaccine platforms, food allergies, autoimmune diseases, and chronic inflammation. Despite challenges, recent advances in nanoparticle formulation support the translation of these technologies into clinical applications for both therapeutic immunomodulation and vaccination.

Photo-Cross-linked DNA Structures Greatly Improves Their Serum Nuclease Resistances and Gene Knock-In Efficiencies

The stabilization and structural integrity of DNA architectures remain significant challenges in their biomedical applications, particularly when inserting functional units into the genome using long single-stranded DNA (lssDNA). To address these challenges, a site-specific photo-cross-linking method is employed. Single-stranded oligonucleotides, containing one or two photosensitive cyanovinylcarbazole nucleoside (CNVK) molecules, are precisely incorporated and cross-linked at the specific sites of ssDNA through base-pairing, followed by rapid UV irradiation at 365 nm. This interstrand photo-cross-linking improves the thermal stability of DNA duplexes and allows this study to afford a tetrahedral DNA nanostructure in a yield of >94%. Most importantly, the photo-cross-linked DNA architectures exhibit high resistances against serum degradation, especially prevent digestion of exonuclease III (exo III), which is common in conventional lambda-processing method. Meanwhile, this photo-cross-linking treatment can significantly improve the knock-in (KI) efficiencies of lssDNA in different cells including 293T, K562, and HepG2, approximately three to eightfold those of the uncross-linked lssDNA, and remain a low cytotoxicity. Given the significantly enhanced nuclease resistance in serum and improved KI efficiencies, this study anticipates that this photo-cross-linking method will become a valuable tool in technologically advanced biomedical applications, such as nanotechnology and nucleic acid therapy.

Hurdles to healing: Overcoming cellular barriers for viral and nonviral gene therapy

Gene delivery offers great potential for treating various diseases, yet its success requires overcoming several biological barriers. These hurdles span from extracellular degradation, reaching the target cells, and inefficient cellular uptake to endosomal entrapment, cytoplasmic transport, nuclear entry, and transcription limitations. Viruses and non-viral vectors deal with these barriers via different mechanisms. Viral vectors, such as adenoviruses, adeno-associated viruses, and lentiviruses use natural mechanisms to efficiently deliver genetic material but face limitations including immunogenicity, cargo capacity, and production complexity. Nonviral vectors, including lipid nanoparticles, polymers, and protein-based systems, offer scalable and safer alternatives but often fall short in overcoming intracellular barriers and achieving high transfection efficiencies. Recent advancements in vector engineering have partially overcome several of these challenges. Ionizable lipids improve endosomal escape while minimizing toxicity. Biodegradable polymers balance efficacy with safety, and engineered protein systems, inspired by viral or bacterial entry mechanisms, integrate multifunctionality for enhanced delivery. Despite these advances, challenges, particularly in achieving robust in vivo translatability, scalability, and reduced immunogenicity, remain. This review synthesizes current knowledge of cellular barriers and the approaches to overcome them, providing a roadmap for designing more efficient gene delivery systems. By addressing these barriers, the field can advance toward safer, and more effective therapies.

mRNA vaccines against HIV: Hopes and challenges

BACKGROUND

Since the introduction of the first licensed mRNA-based vaccines against COVID-19, there has been significant interest in leveraging this technology for other vaccines. An unprecedented surge of mRNA vaccines has emerged in preclinical, clinical, and various research phases since 2020. The rapid development of mRNA formulations, delivery methods, and manufacturing processes has made this trend foreseeable. There is an urgent demand for effective and easily transportable vaccines in regions where the virus is prevalent, and mRNA technology shows promise in addressing this need.

METHODOLOGY

The data was retrieved from various databases, including Google Scholar, PubMed, Science Direct, ClinicalTrials.gov, and government websites. The following terms were used in the search strategies: HIV, vaccines, mRNA vaccines, clinical trials, and preclinical trials. A total of 35 articles were identified and subsequently screened for data regarding mRNA vaccines for HIV.

RESULTS

mRNA vaccines are an effective solution for HIV treatment, as demonstrated by various research studies referenced in the article.

CONCLUSION

This review evaluates the current state of HIV-1 mRNA vaccine development, clarifies various targeting strategies, highlights recent research findings, and provides insights into the challenges and potential solutions associated with these issues. In this review, we have explored mRNA vaccines, focusing on their functional structure, design, manufacturing, and distribution methodologies.

Integrated cell membrane encapsulated PQDs-TK quantum dot nanoclusters with ROS-responsive triggering for efficient and visualized DNA delivery

With the unique photo-physical properties and strong bio-compatibility. Quantum dots (QDs) have sparked interest in biomedical fields such as imaging, biosensing and therapeutics. However, the low stability and insufficient tumor specificity have largely constrained their potential biomedical applications. Here, we reported a cell membrane encapsulated PQDs-TK quantum dots nanoclusters (CM-PQDs-TK) gene delivery system with ROS-responsive triggering for efficient and visualized DNA delivery. CM-PQDs-TK possessed excellent DNA loading capacity and protective ability. The particle size and morphology change suggested that CM-PQDs-TK displayed superior ROS responsiveness. As expected, CM-PQDs-TK had an obvious nanocluster structure, and the particle size was stabilized in the range of 200-300 nm. Compared with PQDs and PQDs-TK, HlM-PQDs-TK/DNA encapsulated by Hela cell membrane has higher uptake efficiency and transfection ability, reaching 67.14 % and 63.41 % in 293 T cells, and the DNA transfection efficiency could still reach 43.98 % even in cancer cells (Hela cells). Moreover, flow cytometry and fluorescence microscopy showedthat nanoclusters could effectively enter tumor cells, and the internal DNA could be effectively released. In this process, PQDs-TK responded to high ROS in tumor cells and greatly improved DNA delivery efficiency. After loading DNA, cell membrane encapsulation technology was used to enhance its biocompatibility and targeting further. This work was anticipated to provide an in-depth understanding of the important role of PEI quantum dots in the field of ROS-responsive intelligent gene carriers and laid a foundation for the design and preparation of novel quantum dots gene carriers.

Emerging dendrimer-based RNA delivery strategies

Dendrimers represent a class of polymers characterized by a highly branched architecture, precise composition, and a multitude of functional groups, garnering significant interest in biomedical applications. These are three-dimensional nanostructures characterized by a high degree of molecular homogeneity, adjustable size, multivalence, significant surface functionality, and high aqueous solubility.Dendrimers, owing to their significant properties, are currently utilized for drug delivery and are under investigation as potential carriers for nucleic acid-based vaccines. Nucleic acid, as a therapeutic molecule, offers several advantages, including safety, efficacy, and cost-effectiveness. These delivery systems may exhibit accelerated development timelines, reduced production costs, and enhanced storage and transportation efficiency. An essential aspect of DNA or RNA delivery technology is the selection of an efficient method of delivery.This review summarizes the classification, preparation, and formulation strategies for dendrimer delivery. Furthermore, the delivery of RNA via dendrimers for a range of disease conditions, including cancer, autoimmune disorders, infectious diseases, neurological disorders, and metabolic disorders, has been investigated and summarized.

Dual-Accelerated Signal Amplification in Biosensing via Spatial Confining Catalytic Hairpin Assembly-Activated Spherical CRISPR/Cas12a System for Trans-Cleavage of Hairpin DNA Reporters

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression and are implicated in various diseases, including cancer. Due to their critical role in diagnostics, there is a growing need for sensitive, specific, and rapid detection methods for miRNAs. In this study, we present a dual-accelerated signal amplification platform for miRNA biosensing, which integrates spatial confining catalytic hairpin assembly (SC-CHA) with spherical CRISPR/Cas12a (S-CRISPR/Cas12a) system for (SC-CHA@S-CRISPR/Cas12a) trans-cleavage of hairpin DNA reporters. The method employs a biotinylated palindrome-rich assembly sequence (PAS) to form DNA nanoballs, which serve as a scaffold for the operation of SC-CHA upon miRNA binding. The SC-CHA products bind with crRNA and Cas 12a protein, activating S-CRISPR/Cas12a system to cleave the hairpin DNA reporter and generate a detectable fluorescence signal. The uniqueness of this system lies in the combined use of DNA nanoballs and hairpin DNA reporters, both of which significantly accelerate reaction kinetics, resulting in rapid signal generation. Additionally, the spherical DNA nanostructure, integrated with the S-CRISPR/Cas12a system, greatly enhances biostability and accelerating reaction kinetics. These features enable the platform to exhibit high sensitivity, with a limit of detection (LOD) as low as 13.75 fM, and excellent specificity, successfully distinguishing miRNA-21 from other miRNAs. The assay is also biostable, demonstrating reliable performance in complex biological samples such as human serum. This dual-acceleration approach offers a promising solution for sensitive, rapid, and specific miRNA biosensing, with potential applications in early cancer diagnosis and clinical monitoring.

Current views and trends of nanomaterials as vectors for gene delivery since the 21st century: a bibliometric analysis

BACKGROUND

Gene therapy is garnering increasing support due to its potential for a "once-delivered, lifelong benefit." The limitations of traditional gene delivery methods have spurred the advancement of bionanomaterials. Despite this progress, a thorough analysis of the evolution, current state, key contributors, focal studies, and future directions of nanomaterials in gene delivery remains absent.

METHODS

This study scrutinizes articles from the Web of Science, spanning 1 January 2 000, to 31 December 2023, employing various online tools for analysis and visualization.

RESULTS

The 21st century has witnessed consistent growth in scholarly work in this domain globally, with notable contributions from China and the US. At the same time, the Chinese Academy of Sciences (CAS), Harvard University, and Massachusetts Institute of Technology (MIT) have emerged as the most productive institutions, with CAS's academician Weihong Tan becoming the field's leading author. While drug delivery and nanoparticles (NPs) have been central themes for two decades, the research focus has shifted from modifying NPs and ultrafine particles to exploring polymer-hybrid NPs, mRNA vaccines, immune responses, green synthesis, and CRISPR/Cas tools.

CONCLUSIONS

This shift marks the transition from nanomaterials to bionanomaterials. The insights provided by this research offer a comprehensive overview of the field and valuable guidance for future investigations.

Nano Approaches to Nucleic Acid Delivery: Barriers, Solutions, and Current Landscape

Nucleic acid (NA) therapy holds tremendous potential for treating a wide range of genetic diseases by the delivery of therapeutic genes into target cells. However, significant challenges exist in safely and effectively delivering these genes to their intended locations. Viral vectors, though efficient, pose risks such as immunogenicity and mutagenesis. This has resulted in growing interest in non-viral, nanoparticle-based NA delivery systems. This review article describes various physiological barriers to NA delivery and explores nanoparticle-based NA delivery systems, including bioengineered nanoparticles, peptides, lipid nanoparticles, and polymeric nanoparticles, highlighting their unique features to overcome in vivo barriers for NA delivery. While these nanoparticle-based NA delivery systems offer a promising alternative to viral vectors, challenges related to cytotoxicity, reproducible synthesis, and cost need to be addressed. The current clinical landscape of NA delivery is also discussed, emphasizing the need for safer, scalable, and cost-effective solutions. Nanoparticles represent a promising future in NA therapy, with the possibility of developing clinically relevant, non-toxic, stable, and non-immunogenic delivery vehicles, paving the way for broader therapeutic applications and improved clinical outcomes.

Aptamer based immunotherapy: a potential solid tumor therapeutic

Aptamer-based immunotherapy can be a new hope for treating solid tumors with personalized and specific approaches toward cancer therapies. Aptamers are small synthetic single-stranded nucleic acids that may bring in a paradigm shift in treating solid tumors. These are highly selective drugs applied in cellular immunotherapy, cytokine modulation, and immune checkpoint suppression. This review provides an overview of the recent advances in aptamer-based technologies with specific key clinical trials involving AON-D21 and AM003. Aptamers are potently active in immune regulation and tumor targeting. However, aptamer stability and bioavailability are seriously compromised by the issues relating to renal clearance and rapid degradation through nucleases. The latter are reviewed here along with novel improvements, some of which involve chemical modifications that greatly enhance stability and prolong the circulation time; exemplary such modifications are PEGylation, cholesterol conjugation, and the synthesis of circular nucleic acids. The regulatory aspect is also crucial. For example, in addition to specific strategies to prevent drug-drug interactions (DDIs) in cancer remediation medications, this paper underscores the need of risk assessment, particularly because of immunogenicity and organ failure. The use of aptamers is expanded by the development of SOMAmers, X-aptamers, and bioinformatics. To make aptamer-based drugs a major part of cancer treatment, future research should concentrate more on resolving existing issues and expanding their beneficial uses.

Topical delivery of siRNA to psoriatic skin model using high molecular weight chitosan derivatives: In vitro and in vivo studies

Psoriasis is a chronic inflammatory skin disease that, like other immune-mediated conditions, may benefit from small interfering RNA (siRNA)-based therapies, which are emerging as a promising alternative by addressing several limitations of current treatments. In this study, topical formulations of chitosan-based vectors were developed to deliver siRNA targeting tumor necrosis factor alpha (TNFα) to inflamed skin. Grafting diisopropylethylamine (DIPEA) and polyethylene glycol (PEG) onto the chitosan backbone enhanced siRNA delivery efficiency under physiological conditions, forming robust polymeric vectors with high structural and colloidal stability. These vectors provided siRNA protection against RNAse degradation and oxidative damage. Additionally, the chitosan derivatives displayed lysozyme-mediated biodegradability comparable to native chitosan, while PEG was released in response to reductive environments, supporting controlled vector disassembly. The PEGylated DIPEA-chitosan/siRNA polyplexes demonstrated positive zeta potentials (up to + 11 mV), particle sizes of 100-200 nm, and very low cytotoxicity in keratinocyte and fibroblast cell lines. In vitro, the polyplexes achieved TNFα knockdown levels (65%) in RAW macrophages, comparable to those obtained with Lipofectamine™. Topical formulations showed enhanced interaction of vectors with skin models (Strat-M® and porcine ear skin) compared to naked siRNA. Furthermore, in vivo studies indicated that hair follicles were a key route for polyplexes to penetrate deeper skin layers. A rodent model of psoriasis induced by imiquimod was treated topically with these vectors, resulting in approximately a 50% reduction in TNFα levels at inflammation sites, decreased immune cell infiltration, and preservation of epidermal structure. These findings collectively underscore the potential of DIPEA-chitosan-based vectors for topical siRNA-based therapies.

Polymeric nanocarriers for therapeutic gene delivery

The recent commercialization of gene products has sparked significant interest in gene therapy, necessitating efficient and precise gene delivery via various vectors. Currently, viral vectors and lipid-based nanocarriers are the predominant choices and have been extensively investigated and reviewed. Beyond these vectors, polymeric nanocarriers also hold the promise in therapeutic gene delivery owing to their versatile functionalities, such as improving the stability, cellar uptake and endosomal escape of nucleic acid drugs, along with precise delivery to targeted tissues. This review presents a brief overview of the status quo of the emerging polymeric nanocarriers for therapeutic gene delivery, focusing on key cationic polymers, nanocarrier types, and preparation methods. It also highlights targeted diseases, strategies to improve delivery efficiency, and potential future directions in this research area. The review is hoped to inspire the development, optimization, and clinical translation of highly efficient polymeric nanocarriers for therapeutic gene delivery.

PROTACs coupled with oligonucleotides to tackle the undruggable

Undruggable targets account for roughly 85% of human disease-related targets and represent a category of therapeutic targets that are difficult to tackle with traditional methods, but their considerable clinical importance. These targets are generally defined by planar functional interfaces and the absence of efficient ligand-binding pockets, making them unattainable for conventional pharmaceutical strategies. The advent of oligonucleotide-based proteolysis-targeting chimeras (PROTACs) has instilled renewed optimism in addressing these challenges. These PROTACs facilitate the targeted degradation of undruggable entities, including transcription factors (TFs) and RNA-binding proteins (RBPs), via proteasome-dependent mechanisms, thereby presenting novel therapeutic approaches for diseases linked to these targets. This review offers an in-depth examination of recent progress in the integration of PROTAC technology with oligonucleotides to target traditionally undruggable proteins, emphasizing the design principles and mechanisms of action of these innovative PROTACs.

From Polydeoxyribonucleotides (PDRNs) to Polynucleotides (PNs): Bridging the Gap Between Scientific Definitions, Molecular Insights, and Clinical Applications of Multifunctional Biomolecules

Polydeoxyribonucleotides (PDRNs) and polynucleotides (PNs) are similar DNA-derived biopolymers that have garnered significant scientific attention since the 1990s for their potential applications in wound healing and skin rejuvenation. These biopolymers exhibit a broad molecular weight (MW) range, typically spanning from 50 to 1500 kDa. However, recent studies have expanded this range to encompass fragments as small as 1 kDa and as large as 10,000 kDa. Clinically, PDRN/PN formulations, commercially available in various galenic forms (gels, creams, serums, masks, and injectables), have demonstrated promising effects in significantly promoting skin regeneration, reducing inflammation, improving skin texture, preventing scar formation, and mitigating wrinkles. Importantly, despite their widespread use in cosmetology and aesthetic dermatology, the interchangeable use of the terms "PDRN" and "PN" in the scientific literature (to describe polymers of varying lengths) has led to considerable confusion within the medical and scientific communities. To specifically address this PDRN/PN ambiguity, this narrative review proposes a standardized structure-based nomenclature for these DNA-derived polymers, the "Marques Polynucleotide Cutoff", set at 1500 kDa. Thus, we propose that the term "PDRN" should be exclusively reserved for small- and medium-chain polymers (MW < 1500 kDa), while the term "PN" should specifically be used to denote longer-chain polymers (MW ≥ 1500 kDa). In a broader perspective, this classification is based on the distinct physicochemical properties and therapeutic effects of these DNA fragments of various MWs, which are comprehensively discussed in the present review.

Spermine Significantly Increases the Transfection Efficiency of Cationic Polymeric Gene Vectors

Background/Objectives: Non-viral vectors have gained recognition for their ability to enhance the safety of gene delivery processes. Among these, polyethyleneimine (PEI) stands out as the most widely utilized cationic polymer due to its accessibility. Traditional methods of modifying PEI, such as ligand conjugation, chemical derivatization, and cross-linking, are associated with intricate preparation procedures, limited transfection efficiency, and suboptimal biocompatibility. Methods: In this investigation, enhanced transfection efficiency was achieved through the straightforward physical blending of PEI carriers with spermine. Results: Transfection assays explored the maximal enhancement potential conferred by spermine, alongside further methodological refinements aimed at optimizing transfection efficacy, showcasing a potential increase of up to 40.7%. Through the comparison of different addition sequences of spermine, the optimal complex PEI/Spermine/DNA for transfection efficiency was selected. Characterization of PEI/Spermine/DNA revealed that, compared to PEI/DNA, its particle size increased to approximately 150 nm. Molecular dynamics simulation results revealed that spermine can enhance the interaction between PEI and DNA, thereby forming a system with lower energy and greater stability. Mechanistic inquiries studies also disclosed that spermine augments the endosomal escape capability of PEI carriers without altering pathways involved in the cellular uptake of gene nanoparticles, thereby facilitating heightened gene expression. Conclusions: PEI-Sper emerges as a promising non-viral vector for gene delivery, distinguished by its simplicity in preparation, cost-effectiveness, and superior transfection efficiency.

Fabrication of lactoferrin-chitosan-etoposide nanoparticles with melatonin via carbodiimide coupling: In-vitro & in-vivo evaluation for colon cancer

This study presents the development of melatonin-coated lactoferrin-chitosan nanoparticles (ETP-CS-LF-MLT-NPs) using ionic gelation and carbodiimide coupling for colorectal cancer treatment. The nanoparticles were characterized by an average size of 208.7 ± 1.25 nm, a zeta potential of 30.77 ± 1.21 mV, and 82.45 % drug encapsulation efficiency. In vitro drug release studies showed sustained, pH-responsive release, with 98.68 ± 4.12 % released at pH 5.5 over 24 h. The nanoparticles exhibited significant cytotoxicity in HCT116 cells (IC50 = 15.32 μg/mL), inducing ROS generation, apoptosis, and G2/M cell cycle arrest, with notable downregulation of BCL2 gene expression. Enhanced cellular uptake due to lactoferrin targeting improved therapeutic efficacy. In In vivo studies, the nanoparticles demonstrated significant tumor reduction and selective colon accumulation in a DMH-induced colorectal cancer rat model, along with improved pharmacokinetics, showing extended plasma circulation and bioavailability compared to free etoposide. Biocompatibility assays, including hemolysis (<1 %), platelet aggregation, and HET-CAM tests, confirmed the safety profiling of the prepared nanoparticles. The nanoparticles also inhibited Proteus mirabilis (ZOI = 1.9 cm) and exhibited promising effects on the gut microbiome of treated animals. Altogether, ETP-CS-LF-MLT-NPs hold great potential for targeted colorectal cancer therapy, improving drug delivery, tumor targeting, bioavailability, and reducing systemic toxicity.

Coacervation for biomedical applications: innovations involving nucleic acids

Gene therapies, drug delivery systems, vaccines, and many other therapeutics, although seeing breakthroughs over the past few decades, still suffer from poor stability, biocompatibility, and targeting. Coacervation, a liquid-liquid phase separation phenomenon, is a pivotal technique increasingly employed to enhance the effectiveness of therapeutics. Through coacervation strategies, many current challenges in therapeutic formulations can be addressed due to the tunable nature of this technique. However, much remains to be explored to enhance these strategies further and scale them from the benchtop to industrial applications. In this review, we highlight the underlying mechanisms of coacervation, elucidating how factors such as pH, ionic strength, temperature, chirality, and charge patterning influence the formation of coacervates and the encapsulation of active ingredients. We then present a perspective on current strategies harnessing these systems, specifically for nucleic acid-based therapeutics. These include peptide-, protein-, and polymer-based approaches, nanocarriers, and hybrid methods, each offering unique advantages and challenges. Nucleic acid-based therapeutics are crucial for designing rapid responses to diseases, particularly in pandemics. While these exciting systems offer many advantages, they also present limitations and challenges which are explored in this work. Exploring coacervation in the biomedical frontier opens new avenues for innovative nucleic acid-based treatments, marking a significant stride towards advanced therapeutic solutions.

Functionalities of pH-responsive DNA nanostructures in tumor-targeted strategies

Nanostructures integrating pH-sensitive DNA motifs have emerged as versatile platforms for active tumor targeting, owing to their ability to undergo conformation changes in response to the common acidic environment of the tumor extracellular matrix and endocytosis pathway. This review summarizes the latest advances in the design and application of various pH-responsive DNA nanostructures for tumor-targeted strategies, including tumor recognition, cell imaging, dynamic nanocarrier construction, and controlled drug release. A comprehensive framework for pH-controlled multi-stage tumor targeting is introduced, addressing the divergences in targeting strategies for extracellular and intracellular environments. The unique attributes, practical performance and application challenges of pH-responsive DNA nanostructures are also critically discussed to provide guidance for future development in this field.

Xeno Nucleic Acids as Functional Materials: From Biophysical Properties to Application

Xeno nucleic acid (XNA) are artificial nucleic acids, in which the chemical composition of the sugar moiety is changed. These modifications impart distinct physical and chemical properties to XNAs, leading to changes in their biological, chemical, and physical stability. Additionally, these alterations influence the binding dynamics of XNAs to their target molecules. Consequently, XNAs find expanded applications as functional materials in diverse fields. This review provides a comprehensive summary of the distinctive biophysical properties exhibited by various modified XNAs and explores their applications as innovative functional materials in expanded fields.

Delivery of mRNA Using Biomimetic Vectors: Progress and Challenges

Messenger RNA (mRNA) is an emerging class of therapeutic agents for treating a wide range of diseases. However, due to the instability and low cell transfection rate of naked mRNA, the expression of delivered mRNA in target cells or tissues in vivo requires delivery strategies. Biomimetic vectors hold advantages such as high biocompatibility, tissue specific targeting ability and efficient delivery mechanisms, potentially overcoming challenges faced by other delivery vectors. In this review, biomimetic vector-based mRNA delivery systems are summarized and discuss the possible challenges and prospects of such delivery systems, which may contribute to the progress and application of mRNA-based therapy in the biomedical field.

Integration of Hybridization Chain Reaction and Protein-Binding Amplification for Long-Term Imaging of Intracellular mRNA: Avoiding Signal Fluctuation

Amplified nanoprobes based on hybridization chain reaction (HCR) have been widely developed for the detection of intracellular low abundance mRNA. However, the formed chain-like assembly decorated with fluorophore would be degraded rapidly by endogenous enzyme, resulting in failure of the long-term fluorescence imaging. To address this issue, herein, a composite signal-amplifying strategy that integrates HCR into protein-binding signal amplification (HPSA) was communicated for the in situ imaging of mRNA by avoiding signal fluctuation. Different from conventional HCR-based nanoprobes (HCR-nanoprobe), the HCR was used as the signal-triggered mode and the amplifying signal generated from in situ fluorophore-protein binding in cells, which can maintain high stability of the signal for a long time. As a proof-of-principle, a nanobeacon based on HPSA (HPSA-nanobeacon) was constructed to detect TK1 mRNA. Taking advantage of the double signal-amplifying mode, the endogenous TK1 mRNA was sensitively detected and the fluorescence signal was maintained for more than 8 h in HepG2 cells. The attempt in this work provides a new option to the current signal-amplifying strategy for sensing nucleic acid targets with high stability, significantly enhancing the acquisition of intracellular molecular information.

Synthesis of Thermoresponsive Chitosan-graft-Poly(N-isopropylacrylamide) Hybrid Copolymer and Its Complexation with DNA

A hybrid synthetic-natural, thermoresponsive graft copolymer composed of poly(N-isopropyl acrylamide) (PNIPAM) side chains, prepared via RAFT polymerization, and a chitosan (Chit) polysaccharide backbone, was synthesized via radical addition-fragmentation reactions using the "grafting to" technique, in aqueous solution. ATR-FTIR, TGA, polyelectrolyte titrations and 1H NMR spectroscopy were employed in order to validate the Chit-g-PNIPAM copolymer chemical structure. Additionally, 1H NMR spectra and back conductometric titration were utilized to quantify the content of grafted PNIPAM side chains. The resulting graft copolymer contains dual functionality, namely both pH responsive free amino groups, with electrostatic complexation/coordination properties, and thermoresponsive PNIPAM side chains. Particle size measurements via dynamic light scattering (DLS) were used to study the thermoresponsive behavior of the Chit-g-PNIPAM copolymer. Thermal properties examined by TGA showed that, by the grafting modification with PNIPAM, the Chit structure became more thermally stable. The lower critical solution temperature (LCST) of the copolymer solution was determined by DLS measurements at 25-45 °C. Furthermore, dynamic and electrophoretic light scattering measurements demonstrated that the Chit-g-PNIPAM thermoresponsive copolymer is suitable of binding DNA molecules and forms nanosized polyplexes at different amino to phosphate groups ratios, with potential application as gene delivery systems.

Advances of Layered Double Hydroxide-Based Materials for Tumor Imaging and Therapy

Layered double hydroxides (LDH) are a class of functional anionic clays that typically consist of orthorhombic arrays of metal hydroxides with anions sandwiched between the layers. Due to their unique properties, including high chemical stability, good biocompatibility, controlled drug loading, and enhanced drug bioavailability, LDHs have many potential applications in the medical field. Especially in the fields of bioimaging and tumor therapy. This paper reviews the research progress of LDHs and their nanocomposites in the field of tumor imaging and therapy. First, the structure and advantages of LDH are discussed. Then, several commonly used methods for the preparation of LDH are presented, including co-precipitation, hydrothermal and ion exchange methods. Subsequently, recent advances in layered hydroxides and their nanocomposites for cancer imaging and therapy are highlighted. Finally, based on current research, we summaries the prospects and challenges of layered hydroxides and nanocomposites for cancer diagnosis and therapy.

DNA nanotechnology-based nucleic acid delivery systems for bioimaging and disease treatment

Nucleic acids, including DNA and RNA, have been considered as powerful and functional biomaterials owing to their programmable structure, good biocompatibility, and ease of synthesis. However, traditional nucleic acid-based probes have always suffered from inherent limitations, including restricted cell internalization efficiency and structural instability. In recent years, DNA nanotechnology has shown great promise for the applications of bioimaging and drug delivery. The attractive superiorities of DNA nanostructures, such as precise geometries, spatial addressability, and improved biostability, have enabled them to be a novel category of nucleic acid delivery systems for biomedical applications. In this review, we introduce the development of DNA nanotechnology, and highlight recent advances of DNA nanostructure-based delivery systems for cellular imaging and therapeutic applications. Finally, we propose the challenges as well as opportunities for the future development of DNA nanotechnology in biomedical research.