Inhaled Nanoformulated mRNA Polyplexes for Protein Production in Lung Epithelium

Nanomedicines via the pulmonary route: a promising strategy to reach the target?

Over the past decades, research on nanomedicines as innovative tools in combating complex pathologies has increased tenfold, spanning fields from infectiology and ophthalmology to oncology. This process has further accelerated since the introduction of SARS-CoV-2 vaccines. When it comes to human health, nano-objects are designed to protect, transport, and improve the solubility of compounds to allow the delivery of active ingredients on their targets. Nanomedicines can be administered by different routes, such as intravenous, oral, intramuscular, or pulmonary routes. In the latter route, nanomedicines can be aerosolized or nebulized to reach the deep lung. This review summarizes existing nanomedicines proposed for inhalation administration, from their synthesis to their potential clinical use. It also outlines the respiratory organs, their structure, and particularities, with a specific emphasis on how these factors impact the administration of nanomedicines. Furthermore, the review addresses the organs accessible through pulmonary administration, along with various pathologies such as infections, genetic diseases, or cancer that can be addressed through inhaled nanotherapeutics. Finally, it examines the existing devices suitable for the aerosolization of nanomedicines and the range of nanomedicines in clinical development.

Tailoring Highly Branched Poly(β-amino ester)s for Efficient and Organ-Selective mRNA Delivery

Development of mRNA therapeutics necessitates targeted delivery technology, while the clinically advanced lipid nanoparticles face difficulty for extrahepatic delivery. Herein, we design highly branched poly(β-amino ester)s (HPAEs) for efficacious organ-selective mRNA delivery through tailoring their chemical compositions and topological structures. Using an "A2+B3+C2" Michael addition platform, a combinatorial library of 219 HPAEs with varied backbone structures, terminal groups, and branching degrees are synthesized. The branched topological structures of HPAEs provide enhanced serum resistance and significantly higher mRNA expression in vivo. The terminal amine structures of HPAEs determine the organ-selectivity of mRNA delivery following systemic administration: morpholine facilitates liver targeting, ethylenediamine favors spleen delivery, while methylpentane enables mRNA delivery to the liver, spleen, and lungs simultaneously. This study represents a comprehensive exploration of the structure-activity relationship governing both the efficiency and organ-selectivity of mRNA delivery by HPAEs, suggesting promising candidates for treating various organ-related diseases.

Design of Experiments Grants Mechanistic Insights into the Synthesis of Spermine-Containing PBAE Copolymers

Successful therapeutic delivery of siRNA with polymeric nanoparticles seems to be a promising but not vastly understood and complicated goal to achieve. Despite years of research, no polymer-based delivery system has been approved for clinical use. Polymers, as a delivery system, exhibit considerable complexity and variability, making their consistent production a challenging endeavor. However, a better understanding of the polymerization process of polymer excipients may improve the reproducibility and material quality for more efficient use in drug products. Here, we present a combination of Design of Experiment and Python-scripted data science to establish a prediction model, from which important parameters can be extracted that influence the synthesis results of polybeta-amino esters (PBAEs), a common type of polymer used preclinically for nucleic acid delivery. We synthesized a library of 27 polymers, each one at different temperatures with different reaction times and educt ratios using an orthogonal central composite (CCO-) design. This design allowed a detailed characterization of factor importance and interactions using a very limited number of experiments. We characterized the polymers by analyzing the resulting composition by 1H-NMR and the size distribution by GPC measurements. To further understand the complex mechanism of block polymerization in a one-pot synthesis, we developed a Python script that helps us to understand possible step-growth steps. We successfully developed and validated a predictive response surface and gathered a deeper understanding of the synthesis of polyspermine-based amphiphilic PBAEs.

Lung-selective nucleic acid vectors generated by in vivo lung-targeting-protein decoration of polyplexes

Nucleic acid drugs show immense therapeutic potential, but achieving selective organ targeting (SORT) for pulmonary disease therapy remains a formidable challenge due to the high mortality rate caused by pulmonary embolism via intravenous administration or the mucus barrier in the respiratory tract via nebulized delivery. To meet this important challenge, we propose a new strategy to prepare lung-selective nucleic-acid vectors generated by in vivo decoration of lung-targeting proteins on bioreducible polyplexes. First, we synthesized polyamidoamines, named pabol and polylipo, to encapsulate and protect nucleic acids, forming polyamidoamines/mRNA polyplexes. Second, bovine serum albumin (BSA) was coated on the surface of these polyplexes, called BSA@polyplexes, including BSA@pabol polyplexes and BSA@polylipo polyplexes, to neutralize excess positive charge, thereby enhancing biosafety. Finally, after subcutaneous injection, proteins, especially vitronectin and fibronectins, attached to the polyplexes, resulting in the formation of lung-selective nucleic-acid vectors that achieve efficient lung targeting.

Reformulating lipid nanoparticles for organ-targeted mRNA accumulation and translation

Fully targeted mRNA therapeutics necessitate simultaneous organ-specific accumulation and effective translation. Despite some progress, delivery systems are still unable to fully achieve this. Here, we reformulate lipid nanoparticles (LNPs) through adjustments in lipid material structures and compositions to systematically achieve the pulmonary and hepatic (respectively) targeted mRNA distribution and expression. A combinatorial library of degradable-core based ionizable cationic lipids is designed, following by optimisation of LNP compositions. Contrary to current LNP paradigms, our findings demonstrate that cholesterol and phospholipid are dispensable for LNP functionality. Specifically, cholesterol-removal addresses the persistent challenge of preventing nanoparticle accumulation in hepatic tissues. By modulating and simplifying intrinsic LNP components, concurrent mRNA accumulation and translation is achieved in the lung and liver, respectively. This targeting strategy is applicable to existing LNP systems with potential to expand the progress of precise mRNA therapy for diverse diseases.

Lung-Specific mRNA Delivery Enabled by Sulfonium Lipid Nanoparticles

Among various mRNA carrier systems, lipid nanoparticles (LNPs) stand out as the most clinically advanced. While current clinical trials of mRNA/LNP therapeutics mainly address liver diseases, the potential of mRNA therapy extends far beyond─yet to be unraveled. To fully unlock the promises of mRNA therapy, there is an urgent need to develop safe and effective LNP systems that can target extrahepatic organs. Here, we report on the development of sulfonium lipid nanoparticles (sLNPs) for systemic mRNA delivery to the lungs. sLNP effectively and specifically delivered mRNA to the lungs following intravenous administration in mice. No evidence of lung and systemic inflammation or toxicity in major organs was induced by sLNP. Our findings demonstrated that the newly developed lung-specific sLNP platform is both safe and efficacious. It holds great promise for advancing the development of new mRNA-based therapies for the treatment of lung-associated diseases and conditions.

Recent Developments in Aerosol Pulmonary Drug Delivery: New Technologies, New Cargos, and New Targets

There is nothing like a global pandemic to motivate the need for improved respiratory treatments and mucosal vaccines. Stimulated by the COVID-19 pandemic, pulmonary aerosol drug delivery has seen a flourish of activity, building on the prior decades of innovation in particle engineering, inhaler device technologies, and clinical understanding. As such, the field has expanded into new directions and is working toward the efficient delivery of increasingly complex cargos to address a wider range of respiratory diseases. This review seeks to highlight recent innovations in approaches to personalize inhalation drug delivery, deliver complex cargos, and diversify the targets treated and prevented through pulmonary drug delivery. We aim to inform readers of the emerging efforts within the field and predict where future breakthroughs are expected to impact the treatment of respiratory diseases.

A Lung-Expressing mRNA Delivery Platform with Tunable Activity in Hypoxic Environments

Messenger RNA (mRNA) delivery platforms often facilitate protein expression in the liver following intravenous injection and have been optimized for use in normally oxygenated cells (21% O2 atmosphere). However, there is a growing need for mRNA therapy in diseases affecting non-liver organs, such as the lungs. Additionally, many diseases are characterized by hypoxia (<21% O2 atmosphere), a state of abnormally low oxygenation in cells and tissues that can reduce the efficacy of mRNA therapies by upwards of 80%. Here, we report a Tunable Lung-Expressing Nanoparticle Platform (TULEP) for mRNA delivery, whose properties can be readily tuned for optimal expression in hypoxic environments. Briefly, our study begins with the synthesis and characterization of a novel amino acrylate polymer that can be effectively complexed with mRNA payloads into TULEPs. We study the efficacy and mechanism of mRNA delivery using TULEP, including analysis of the cellular association, endocytosis mechanisms, endosomal escape, and protein expression in a lung cell line. We then evaluate TULEP under hypoxic conditions and address hypoxia-related deficits in efficacy by making our system tunable with adenosine triphosphate (ATP). Finally, we conclude our study with an in vivo analysis of mRNA expression, biodistribution, and tolerability of the TULEP platform in mice. In presenting these data, we hope that our work highlights the utility of TULEPs for tunable and effective mRNA delivery while more broadly highlighting the utility of considering oxygen levels when developing mRNA delivery platforms.

Realveolarization with inhalable mucus-penetrating lipid nanoparticles for the treatment of pulmonary fibrosis in mice

The stemness loss-associated dysregeneration of impaired alveolar type 2 epithelial (AT2) cells abolishes the reversible therapy of idiopathic pulmonary fibrosis (IPF). We here report an inhalable mucus-penetrating lipid nanoparticle (LNP) for codelivering dual mRNAs, promoting realveolarization via restoring AT2 stemness for IPF treatment. Inhalable LNPs were first formulated with dipalmitoylphosphatidylcholine and our in-house-made ionizable lipids for high-efficiency pulmonary mucus penetration and codelivery of dual messenger RNAs (mRNAs), encoding cytochrome b5 reductase 3 and bone morphogenetic protein 4, respectively. After being inhaled in a bleomycin model, LNPs reverses the mitochondrial dysfunction through ameliorating nicotinamide adenine dinucleotide biosynthesis, which inhibits the accelerated senescence of AT2 cells. Concurrently, pathological epithelial remodeling and fibroblast activation induced by impaired AT2 cells are terminated, ultimately prompting alveolar regeneration. Our data demonstrated that the mRNA-LNP system exhibited high protein expression in lung epithelial cells, which markedly extricated the alveolar collapse and prolonged the survival of fibrosis mice, providing a clinically viable strategy against IPF.

In vivo editing of lung stem cells for durable gene correction in mice

In vivo genome correction holds promise for generating durable disease cures; yet, effective stem cell editing remains challenging. In this work, we demonstrate that optimized lung-targeting lipid nanoparticles (LNPs) enable high levels of genome editing in stem cells, yielding durable responses. Intravenously administered gene-editing LNPs in activatable tdTomato mice achieved >70% lung stem cell editing, sustaining tdTomato expression in >80% of lung epithelial cells for 660 days. Addressing cystic fibrosis (CF), NG-ABE8e messenger RNA (mRNA)-sgR553X LNPs mediated >95% cystic fibrosis transmembrane conductance regulator (CFTR) DNA correction, restored CFTR function in primary patient-derived bronchial epithelial cells equivalent to Trikafta for F508del, corrected intestinal organoids and corrected R553X nonsense mutations in 50% of lung stem cells in CF mice. These findings introduce LNP-enabled tissue stem cell editing for disease-modifying genome correction.

Beyond Lipids: Exploring Advances in Polymeric Gene Delivery in the Lipid Nanoparticles Era

The recent success of gene therapy during the COVID-19 pandemic has underscored the importance of effective and safe delivery systems. Complementing lipid-based delivery systems, polymers present a promising alternative for gene delivery. Significant advances have been made in the recent past, with multiple clinical trials progressing beyond phase I and several companies actively working on polymeric delivery systems which provides assurance that polymeric carriers can soon achieve clinical translation. The massive advantage of structural tunability and vast chemical space of polymers is being actively leveraged to mitigate shortcomings of traditional polycationic polymers and improve the translatability of delivery systems. Tailored polymeric approaches for diverse nucleic acids and for specific subcellular targets are now being designed to improve therapeutic efficacy. This review describes the recent advances in polymer design for improved gene delivery by polyplexes and covalent polymer-nucleic acid conjugates. The review also offers a brief note on novel computational techniques for improved polymer design. The review concludes with an overview of the current state of polymeric gene therapies in the clinic as well as future directions on their translation to the clinic.

Understanding Mucosal Physiology and Rationale of Formulation Design for Improved Mucosal Immunity

The oral and nasal cavities serve as critical gateways for infectious pathogens, with microorganisms primarily gaining entry through these routes. Our first line of defense against these invaders is the mucosal membrane, a protective barrier that shields the body's internal systems from infection while also contributing to vital functions like air and nutrient intake. One of the key features of this mucosal barrier is its ability to protect the physiological system from pathogens. Additionally, mucosal tolerance plays a crucial role in maintaining homeostasis by regulating the pH and water balance within the body. Recognizing the importance of the mucosal barrier, researchers have developed various mucosal formulations to enhance the immune response. Mucosal vaccines, for example, deliver antigens directly to mucosal tissues, triggering local immune stimulation and ultimately inducing systemic immunity. Studies have shown that lipid-based formulations such as liposomes and virosomes can effectively elicit both local and systemic immune responses. Furthermore, mucoadhesive polymeric particles, with their prolonged delivery to target sites, have demonstrated an enhanced immune response. This Review delves into the critical role of material selection and delivery approaches in optimizing mucosal immunity.

Cationic Lipid Pairs Enhance Liver-to-Lung Tropism of Lipid Nanoparticles for In Vivo mRNA Delivery

Much of current clinical interest has focused on mRNA therapeutics for the treatment of lung-associated diseases, such as infections, genetic disorders, and cancers. However, the safe and efficient delivery of mRNA therapeutics to the lungs, especially to different pulmonary cell types, is still a formidable challenge. In this paper, we proposed a cationic lipid pair (CLP) strategy, which utilized the liver-targeted ionizable lipid and its derived quaternary ammonium lipid as the CLP to improve liver-to-lung tropism of four-component lipid nanoparticles (LNPs) for in vivo mRNA delivery. Interestingly, the structure-activity investigation identified that using liver-targeted ionizable lipids with higher mRNA delivery performance and their derived lipid counterparts is the optimal CLP design for improving lung-targeted mRNA delivery. The CLP strategy was also verified to be universal and suitable for clinically available ionizable lipids such as SM-102 and ALC-0315 to develop lung-targeted LNP delivery systems. Moreover, we demonstrated that CLP-based LNPs were safe and exhibited potent mRNA transfection in pulmonary endothelial and epithelial cells. As a result, we provided a powerful CLP strategy for shifting the mRNA delivery preference of LNPs from the liver to the lungs, exhibiting great potential for broadening the application scenario of mRNA-based therapy.

Recent Progress in Nucleic Acid Pulmonary Delivery toward Overcoming Physiological Barriers and Improving Transfection Efficiency

Pulmonary delivery of therapeutic agents has been considered the desirable administration route for local lung disease treatment. As the latest generation of therapeutic agents, nucleic acid has been gradually developed as gene therapy for local diseases such as asthma, chronic obstructive pulmonary diseases, and lung fibrosis. The features of nucleic acid, specific physiological structure, and pathophysiological barriers of the respiratory tract have strongly affected the delivery efficiency and pulmonary bioavailability of nucleic acid, directly related to the treatment outcomes. The development of pharmaceutics and material science provides the potential for highly effective pulmonary medicine delivery. In this review, the key factors and barriers are first introduced that affect the pulmonary delivery and bioavailability of nucleic acids. The advanced inhaled materials for nucleic acid delivery are further summarized. The recent progress of platform designs for improving the pulmonary delivery efficiency of nucleic acids and their therapeutic outcomes have been systematically analyzed, with the application and the perspectives of advanced vectors for pulmonary gene delivery.

Microfluidic Platform Enables Shearless Aerosolization of Lipid Nanoparticles for mRNA Inhalation

Leveraging the extensive surface area of the lungs for gene therapy, the inhalation route offers distinct advantages for delivery. Clinical nebulizers that employ vibrating mesh technology are the standard choice for converting liquid medicines into aerosols. However, they have limitations when it comes to delivering mRNA through inhalation, including severe damage to nanoparticles due to shearing forces. Here, we introduce a microfluidic aerosolization platform (MAP) that preserves the structural and physicochemical integrity of lipid nanoparticles, enabling safe and efficient delivery of mRNA to the respiratory system. Our results demonstrated the superiority of the MAP over the conventional vibrating mesh nebulizer, as it avoided problems such as particle aggregation, loss of mRNA encapsulation, and deformation of the nanoparticle morphology. Notably, aerosolized nanoparticles generated by the microfluidic device led to enhanced transfection efficiency across various cell lines. In vivo experiments with mice that inhaled these aerosolized nanoparticles revealed successful lung-specific mRNA transfection without observable signs of toxicity. This MAP may represent an advancement for the pulmonary gene therapy, enabling precise and effective delivery of aerosolized nanoparticles.

Interaction of γ-Polyglutamic Acid/Polyethyleneimine/Plasmid DNA Ternary Complexes with Serum Components Plays a Crucial Role in Transfection in Mice

Typical examples of non-viral vectors are binary complexes of plasmid DNA with cationic polymers such as polyethyleneimine (PEI). However, problems such as cytotoxicity and hemagglutination, owing to their positively charged surfaces, hinder their in vivo use. Coating binary complexes with anionic polymers, such as γ-polyglutamic acid (γ-PGA), can prevent cytotoxicity and hemagglutination. However, the role of interactions between these complexes and serum components in in vivo gene transfer remains unclear. In this study, we analyzed the contribution of serum components to in vivo gene transfer using PEI/plasmid DNA binary complexes and γ-PGA/PEI/plasmid DNA ternary complexes. In binary complexes, heat-labile components in the serum greatly contribute to the hepatic and splenic gene expression of the luciferase gene. In contrast, serum albumin and salts affected the hepatic and splenic gene expression in the ternary complexes. Changes in physicochemical characteristics, such as increased particle size and decreased absolute values of ζ-potential, might be involved in the enhanced gene expression. These findings would contribute to a better understanding of in vivo non-viral gene transfer using polymers, such as PEI and γ-PGA.

Strategies for non-viral vectors targeting organs beyond the liver

In recent years, nanoparticles have evolved to a clinical modality to deliver diverse nucleic acids. Rising interest in nanomedicines comes from proven safety and efficacy profiles established by continuous efforts to optimize physicochemical properties and endosomal escape. However, despite their transformative impact on the pharmaceutical industry, the clinical use of non-viral nucleic acid delivery is limited to hepatic diseases and vaccines due to liver accumulation. Overcoming liver tropism of nanoparticles is vital to meet clinical needs in other organs. Understanding the anatomical structure and physiological features of various organs would help to identify potential strategies for fine-tuning nanoparticle characteristics. In this Review, we discuss the source of liver tropism of non-viral vectors, present a brief overview of biological structure, processes and barriers in select organs, highlight approaches available to reach non-liver targets, and discuss techniques to accelerate the discovery of non-hepatic therapies.

From structural design to delivery: mRNA therapeutics for cancer immunotherapy

mRNA therapeutics have emerged as powerful tools for cancer immunotherapy in accordance with their superiority in expressing all sequence-known proteins in vivo. In particular, with a small dosage of delivered mRNA, antigen-presenting cells (APCs) can synthesize mutant neo-antigens and multi-antigens and present epitopes to T lymphocytes to elicit antitumor effects. In addition, expressing receptors like chimeric antigen receptor (CAR), T-cell receptor (TCR), CD134, and immune-modulating factors including cytokines, interferons, and antibodies in specific cells can enhance immunological response against tumors. With the maturation of in vitro transcription (IVT) technology, large-scale and pure mRNA encoding specific proteins can be synthesized quickly. However, the clinical translation of mRNA-based anticancer strategies is restricted by delivering mRNA into target organs or cells and the inadequate endosomal escape efficiency of mRNA. Recently, there have been some advances in mRNA-based cancer immunotherapy, which can be roughly classified as modifications of the mRNA structure and the development of delivery systems, especially the lipid nanoparticle platforms. In this review, the latest strategies for overcoming the limitations of mRNA-based cancer immunotherapies and the recent advances in delivering mRNA into specific organs and cells are summarized. Challenges and opportunities for clinical applications of mRNA-based cancer immunotherapy are also discussed.

Recent advances in nanoparticulate RNA delivery systems

Nanoparticle-based RNA delivery has shown great progress in recent years with the approval of two mRNA vaccines for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and a liver-targeted siRNA therapy. Here, we discuss the preclinical and clinical advancement of new generations of RNA delivery therapies along multiple axes. Improvements in cargo design such as RNA circularization and data-driven untranslated region optimization can drive better mRNA expression. New materials discovery research has driven improved delivery to extrahepatic targets such as the lung and splenic immune cells, which could lead to pulmonary gene therapy and better cancer vaccines, respectively. Other organs and even specific cell types can be targeted for delivery via conjugation of small molecule ligands, antibodies, or peptides to RNA delivery nanoparticles. Moreover, the immune response to any RNA delivery nanoparticle plays a crucial role in determining efficacy. Targeting increased immunogenicity without induction of reactogenic side effects is crucial for vaccines, while minimization of immune response is important for gene therapies. New developments have addressed each of these priorities. Last, we discuss the range of RNA delivery clinical trials targeting diverse organs, cell types, and diseases and suggest some key advances that may play a role in the next wave of therapies.

Nanotechnology of inhalable vaccines for enhancing mucosal immunity

Vaccines are the cornerstone of world health. The majority of vaccines are formulated as injectable products, facing the drawbacks of cold chain transportation, needle-stick injuries, and primary systemic immunity. Inhalable vaccines exhibited unique advantages due to their small dose, easy to use, quick effect, and simultaneous induction of mucosal and systemic responses. Facing global pandemics, especially the coronavirus disease 2019 (COVID-19), a majority of inhalable vaccines are in preclinical or clinical trials. A better understanding of advanced delivery technologies of inhalable vaccines may provide new scientific insights for developing inhalable vaccines. In this review article, detailed immune mechanisms involving mucosal, cellular, and humoral immunity were described. The preparation methods of inhalable vaccines were then introduced. Advanced nanotechnologies of inhalable vaccines containing inhalable nucleic acid vaccines, inhalable adenovirus vector vaccines, novel adjuvant-assisted inhalable vaccines, and biomaterials for inhalable vaccine delivery were emphatically discussed. Meanwhile, the latest clinical progress in inhalable vaccines for COVID-19 and tuberculosis was discussed.

Soybean Oil-Derived Lipids for Efficient mRNA Delivery

The rapid progress in the development of COVID-19 mRNA vaccines during the initial year of the pandemic has highlighted the significance of lipid nanoparticles in therapeutic delivery. Various lipid types have been investigated for the effective delivery of mRNA, each with unique functions and versatile applications. These range from their use in cancer immunotherapy and gene editing to their role in developing vaccines against infectious diseases. Nonetheless, continued exploration of novel lipids and synthetic approaches is necessary to further advance the understanding and expand the techniques for optimizing mRNA delivery. In this work, new lipids derived from FDA-approved soybean oil are facilely synthesized and these are employed for efficient mRNA delivery. EGFP and Fluc mRNA are used to evaluate the delivery efficacy of the lipid formulations both in vitro and in vivo. Furthermore, organ-specific targeting capabilities are observed in certain formulations, and their outstanding performance is demonstrated in delivering Cre mRNA for gene editing. These results showcase the potential of soybean oil-derived lipids in mRNA delivery, offering utility across a broad spectrum of bioapplications.

Combinatorial development of nebulized mRNA delivery formulations for the lungs

Inhaled delivery of mRNA has the potential to treat a wide variety of diseases. However, nebulized mRNA lipid nanoparticles (LNPs) face several unique challenges including stability during nebulization and penetration through both cellular and extracellular barriers. Here we develop a combinatorial approach addressing these barriers. First, we observe that LNP formulations can be stabilized to resist nebulization-induced aggregation by altering the nebulization buffer to increase the LNP charge during nebulization, and by the addition of a branched polymeric excipient. Next, we synthesize a combinatorial library of ionizable, degradable lipids using reductive amination, and evaluate their delivery potential using fully differentiated air-liquid interface cultured primary lung epithelial cells. The final combination of ionizable lipid, charge-stabilized formulation and stability-enhancing excipient yields a significant improvement in lung mRNA delivery over current state-of-the-art LNPs and polymeric nanoparticles.

Intratracheal administration of programmable DNA nanostructures combats acute lung injury by targeting microRNA-155

Acute lung injury (ALI) is an acute inflammatory process that can result in life-threatening consequences. Programmable DNA nanostructures have emerged as excellent nanoplatforms for microRNA-based therapeutics, offering potential nanomedicines for ALI treatment. Nonetheless, the traditional systematic administration of nanomedicines is constrained by low delivery efficiency, poor pharmacokinetics, and nonspecific side effects. Here, we identify macrophage microRNA-155 as a novel therapeutic target using the magnetic bead sorting technique. We further construct a DNA nanotubular nucleic acid drug antagonizing microRNA-155 (NT-155) for ALI treatment through intratracheal administration. Flow cytometry results demonstrate that NT-155, when inhaled, is taken up much more effectively by macrophages and dendritic cells in the bronchoalveolar lavage fluid of ALI mice. Furthermore, NT-155 effectively silences the overexpressed microRNA-155 in macrophages and exerts excellent inflammation inhibition effects in vitro and ALI mouse models. Mechanistically, NT-155 suppresses microRNA-155 expression and activates its target gene SOCS1, inhibiting the p-P65 signaling pathway and suppressing proinflammatory cytokine secretion. The current study suggests that deliberately designed nucleic acid drugs are promising nanomedicines for ALI treatment and the local administration may open up new practical applications of DNA in the future.

Amphiphilic Block Copolymer Nanostructures as a Tunable Delivery Platform: Perspective and Framework for the Future Drug Product Development

Nanoformulation of active payloads or pharmaceutical ingredients (APIs) has always been an area of interest to achieve targeted, sustained, and efficacious delivery. Various delivery platforms have been explored, but loading and delivery of APIs have been challenging because of the chemical and structural properties of these molecules. Polymersomes made from amphiphilic block copolymers (ABCPs) have shown enormous promise as a tunable API delivery platform and confer multifold advantages over lipid-based systems. For example, a COVID booster vaccine comprising polymersomes encapsulating spike protein (ACM-001) has recently completed a Phase I clinical trial and provides a case for developing safe drug products based on ABCP delivery platforms. However, several limitations need to be resolved before they can reach their full potential. In this Perspective, we would like to highlight such aspects requiring further development for translating an ABCP-based delivery platform from a proof of concept to a viable commercial product.

mRNA Delivery: Challenges and Advances through Polymeric Soft Nanoparticles

Single-stranded messenger ribonucleic acid (mRNA) plays a pivotal role in transferring genetic information, and tremendous effort has been devoted over the years to utilize its transcription efficacy in therapeutic interventions for a variety of diseases with high morbidity and mortality. Lipid nanocarriers have been extensively investigated for mRNA delivery and enabled the rapid and successful development of mRNA vaccines against SARS-CoV-2. Some constraints of lipid nanocarriers have encouraged the development of alternative delivery systems, such as polymer-based soft nanoparticles, which offer a modular gene delivery platform. Such macromolecule-based nanocarriers can be synthetically articulated for tailored parameters including mRNA protection, loading efficacy, and targeted release. In this review, we highlight recent advances in the development of polymeric architectures for mRNA delivery, their limitations, and the challenges that still exist, with the aim of expediting further research and the clinical translation of such formulations.

Trends in the synthetic polymer delivery of RNA

Ribonucleic acid (RNA) has emerged as one of the most promising therapeutic payloads in the field of gene therapy. There are many unique types of RNA that allow for a range of applications including vaccination, protein replacement therapy, autoimmune disease treatment, gene knockdown and gene editing. However, RNA triggers the host immune system, is vulnerable to degradation and has a low proclivity to enter cells spontaneously. Therefore, a delivery vehicle is required to facilitate the protection and uptake of RNA therapeutics into the desired host cells. Lipid nanoparticles have emerged as one of the only clinically approved vehicles for genetic payloads, including in the COVID-19 messenger RNA vaccines. While lipid nanoparticles have distinct advantages, they also have drawbacks, including strong immune stimulation, complex manufacturing and formulation heterogeneity. In contrast, synthetic polymers are a widely studied group of gene delivery vehicles and boast distinct advantages, including biocompatibility, tunability, inexpensiveness, simple formulation and ease of modification. Some classes of polymers enhance efficient transfection efficiency, and lead to lower stimulation of the host immune system, making them more viable candidates for non-vaccine-related applications of RNA medicines. This review aims to identify the most promising classes of synthetic polymers, summarize recent research aimed at moving them into the clinic and postulate the future steps required for unlocking their full potential.

Recent progress of non-linear topological structure polymers: synthesis, and gene delivery

Currently, many types of non-linear topological structure polymers, such as brush-shaped, star, branched and dendritic structures, have captured much attention in the field of gene delivery and nanomedicine. Compared with linear polymers, non-linear topological structural polymers offer many advantages, including multiple terminal groups, broad and complicated spatial architecture and multi-functionality sites to enhance gene delivery efficiency and targeting capabilities. Nevertheless, the complexity of their synthesis process severely hampers the development and applications of nonlinear topological polymers. This review aims to highlight various synthetic approaches of non-linear topological architecture polymers, including reversible-deactivation radical polymerization (RDRP) including atom-transfer radical polymerization (ATRP), nitroxide-mediated polymerization (NMP), reversible addition-fragmentation chain transfer (RAFT) polymerization, click chemistry reactions and Michael addition, and thoroughly discuss their advantages and disadvantages, as well as analyze their further application potential. Finally, we comprehensively discuss and summarize different non-linear topological structure polymers for genetic materials delivering performance both in vitro and in vivo, which indicated that topological effects and nonlinear topologies play a crucial role in enhancing the transfection performance of polymeric vectors. This review offered a promising guideline for the design and development of novel nonlinear polymers and facilitated the development of a new generation of polymer-based gene vectors.

Microfluidic platform enables shear-less aerosolization of lipid nanoparticles for messenger RNA inhalation

Leveraging the extensive surface area of the lungs for gene therapy, inhalation route offers distinct advantages for delivery. Clinical nebulizers that employ vibrating mesh technology are the standard choice for converting liquid medicines into aerosols. However, they have limitations when it comes to delivering mRNA through inhalation, including severe damage to nanoparticles due to shearing forces. Here, we introduce a novel microfluidic aerosolization platform (MAP) that preserves the structural and physicochemical integrity of lipid nanoparticles, enabling safe and efficient mRNA delivery to the respiratory system. Our results demonstrated the superiority of the novel MAP over the conventional vibrating mesh nebulizer, as it avoided problems such as particle aggregation, loss of mRNA encapsulation, and deformation of nanoparticle morphology. Notably, aerosolized nanoparticles generated by the microfluidic device led to enhanced transfection efficiency across various cell lines. In vivo experiments with mice that inhaled these aerosolized nanoparticles revealed successful, lung-specific mRNA transfection without observable signs of toxicity. This pioneering MAP represents a significant advancement for the pulmonary gene therapy, enabling precise and effective delivery of aerosolized nanoparticles.

mRNA Vaccine Nanoplatforms and Innate Immunity

mRNA-based vaccine technology has been significantly developed and enhanced, particularly highlighted by the authorization of mRNA vaccines for addressing the COVID-19 pandemic. Various biomaterials are developed in nano-scales and applied as mRNA vaccine delivery platforms. However, how these mRNA nanoplatforms influence immune responses has not been thoroughly studied. Hence, we have reviewed the current understanding of various mRNA vaccine platforms. We discussed the possible pathways through which these platforms moderate the host's innate immunity and contribute to the development of adaptive immunity. We shed light on their development in reducing biotoxicity and enhancing antigen delivery efficiency. Beyond the built-in adjuvanticity of mRNA vaccines, we propose that supplementary adjuvants may be required to fine-tune and precisely control innate immunity and subsequent adaptive immune responses.

Delivery of mRNA with Histidine-Lysine Peptides

Transfection with mRNA has been considered superior to that with plasmids since the mRNA can be translated to a protein in the cytosol without entering the nucleus. One disadvantage of using mRNA is its susceptibility to enzymatic biodegradability, and consequently, significant research has occurred to determine nonviral carriers that will sufficiently stabilize this nucleic acid for cellular transport. Histidine-lysine peptides (HK) are one such class of mRNA carriers, which we think serves as a model for other peptides and polymeric carrier systems. When the HK peptide and mRNA are mixed and interact through ionic and nonionic bonds, mRNA polyplexes are formed, which can transfect cells. In contrast to linear HK peptides, branched HK peptides protected and efficiently transfected mRNA into cells. After describing the preparation and biophysical characterization of these polyplexes, we will provide protocols for in vitro and in vivo transfection for these mRNA polyplexes.

Building a Better Silver Bullet: Current Status and Perspectives of Non-Viral Vectors for mRNA Vaccines

In recent years, messenger RNA (mRNA) vaccines have exhibited great potential to replace conventional vaccines owing to their low risk of insertional mutagenesis, safety and efficacy, rapid and scalable production, and low-cost manufacturing. With the great achievements of chemical modification and sequence optimization methods of mRNA, the key to the success of mRNA vaccines is strictly dependent on safe and efficient gene vectors. Among various delivery platforms, non-viral mRNA vectors could represent perfect choices for future clinical translation regarding their safety, sufficient packaging capability, low immunogenicity, and versatility. In this review, the recent progress in the development of non-viral mRNA vectors is focused on. Various organic vectors including lipid nanoparticles (LNPs), polymers, peptides, and exosomes for efficient mRNA delivery are presented and summarized. Furthermore, the latest advances in clinical trials of mRNA vaccines are described. Finally, the current challenges and future possibilities for the clinical translation of these promising mRNA vectors are also discussed.

A Versatile Platform to Generate Shell-Cross-Linked Uniform Π-Conjugated Nanofibers with Controllable Length, High Morphological Stability, and Facile Surface Tailorability

Living crystallization-driven self-assembly (CDSA) has emerged as an efficient route to generate π-conjugated-polymer-based nanofibers (CPNFs) with promising applications from photocatalysis to biomedicine. However, the lack of efficient tools to endow CPNFs with morphological stability and surface tailorability becomes a frustrating hindrance for expanding application spectrum of CPNFs. Herein, a facile strategy to fabricate length-controllable OPV-based (OPV = oligo(p-phenylenevinylene)) CPNFs containing a cross-linked shell with high morphological stability and facile surface tailorability through the combination of living CDSA and thiol-ene chemistry by using OPV5 -b-PNAAM32 (PNAAM = poly(N-allyl acrylamide)) as a model is reported. Uniform fiber-like micelles with tunable length can be generated by self-seeding of living CDSA. By taking advantage of radical thiol-ene reaction between vinyls of PNAAM corona and four-arm thiols, the shell of micelles can be cross-linked with negligible destruction of structure of vinylene-containing OPV core. The resulting micelles show high morphological stability in NaCl solution and PBS buffer, even upon heating at 80 °C. The introduced extra thiol groups in the cross-linked shell can be further employed to install extra functional moieties via convenient thiol-Michael-type reaction. Given the negligible cytotoxicity of resulting CPNFs, this strategy opens an avenue to fabricate various CPNFs of diverse functionalities for biomedicine.

Fluorinated amphiphilic Poly(β-Amino ester) nanoparticle for highly efficient and specific delivery of nucleic acids to the Lung capillary endothelium

Endothelial cell dysfunction occurs in a variety of acute and chronic pulmonary diseases including pulmonary hypertension, viral and bacterial pneumonia, bronchopulmonary dysplasia, and congenital lung diseases such as alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV). To correct endothelial dysfunction, there is a critical need for the development of nanoparticle systems that can deliver drugs and nucleic acids to endothelial cells with high efficiency and precision. While several nanoparticle delivery systems targeting endothelial cells have been recently developed, none of them are specific to lung endothelial cells without targeting other organs in the body. In the present study, we successfully solved this problem by developing non-toxic poly(β-amino) ester (PBAE) nanoparticles with specific structure design and fluorinated modification for high efficiency and specific delivery of nucleic acids to the pulmonary endothelial cells. After intravenous administration, the PBAE nanoparticles were capable of delivering non-integrating DNA plasmids to lung microvascular endothelial cells but not to other lung cell types. IVIS whole body imaging and flow cytometry demonstrated that DNA plasmid were functional in the lung endothelial cells but not in endothelial cells of other organs. Fluorination of PBAE was required for lung endothelial cell-specific targeting. Hematologic analysis and liver and kidney metabolic panels demonstrated the lack of toxicity in experimental mice. Thus, fluorinated PBAE nanoparticles can be an ideal vehicle for gene therapy targeting lung microvascular endothelium in pulmonary vascular disorders.

Quaternization drives spleen-to-lung tropism conversion for mRNA-loaded lipid-like nanoassemblies

Background: As the overwhelming majority of advanced mRNA delivery systems are preferentially accumulated in the liver, there is an accelerating growth in the demand for the development of non-liver mRNA delivery platforms. Methods: In this study, we prepared cationic lipid-like nanoassemblies through a N-quaternizing strategy. Their physicochemical properties, in vitro mRNA delivery efficiency, and organ tropism in mice were investigated. Results: Introduction of quaternary ammonium groups onto lipid-like nanoassemblies not only enhances their mRNA delivery performance in vitro, but also completely alters their tropism from the spleen to the lung after intravenous administration in mice. Quaternized lipid-like nanoassemblies exhibit ultra-high specificity to the lung and are predominantly taken up by pulmonary immune cells, leading to over 95% of exogenous mRNA translation in the lungs. Such mRNA delivery carriers are stable even after more than one-year storage at ambient temperature. Conclusions: Quaternization provides an alternative method for design of new lung-targeted mRNA delivery systems without incorporation of targeting ligands, which should extend the therapeutic applicability of mRNA to lung diseases.

Bioinspired Spatiotemporal Management toward RNA Therapies

Ribonucleic acid (RNA)-based therapies have become an attractive topic in disease intervention, especially with some that have been approved by the FDA such as the mRNA COVID-19 vaccine (Comirnaty, Pfizer-BioNTech, and Spikevax, Moderna) and Patisiran (siRNA-based drug for liver delivery). However, extensive applications are still facing challenges in delivering highly negatively charged RNA to the targeted site. Therapeutic delivery strategies including RNA modifications, RNA conjugates, and RNA polyplexes and delivery platforms such as viral vectors, nanoparticle-based delivery platforms, and hydrogel-based delivery platforms as potential nucleic acid-releasing depots have been developed to enhance their cellular uptake and protect nucleic acid from being degraded by immune systems. Here, we review the growing number of viral vectors, nanoparticles, and hydrogel-based RNA delivery systems; describe RNA loading/release mechanism induced by environmental stimulations including light, heat, pH, or enzyme; discuss their physical or chemical interactions; and summarize the RNA therapeutics release period (temporal) and their target cells/organs (spatial). Finally, we describe current concerns, highlight current challenges and future perspectives of RNA-based delivery systems, and provide some possible research areas that provide opportunities for clinical translation of RNA delivery carriers.

Delivery of nucleic acids using nanomaterials

The increasing number of approved nucleic acid therapeutics demonstrates the potential for the prevention and treatment of a broad spectrum of diseases. This trend underscores the significant impact and promise of nucleic acid-based treatments in the field of medicine. Nevertheless, employing nucleic acids as therapeutics is challenging due to their susceptibility to degradation by nucleases and their unfavorable physicochemical characteristics that hinder delivery into cells. Appropriate vectors play a pivotal role in improving nucleic acid stability and delivering nucleic acids into specific cells. The maturation of delivery systems has led to breakthroughs in the development of therapeutics based on nucleic acids such as DNA, siRNA, and mRNA. Non-viral vectors have gained prominence among the myriad of nanomaterials due to low immunogenicity, ease of manufacturing, and simplicity of cost-effective, large-scale production. Here, we provide an overview of the recent advancements in nanomaterials for nucleic acid delivery. Specifically, we give a detailed introduction to the characteristics of polymers, lipids, and polymer-lipid hybrids, and provide comprehensive descriptions of their applications in nucleic acid delivery. Also, biological barriers, administration routes, and strategies for organ-selective delivery of nucleic acids are discussed. In summary, this review offers insights into the rational design of next-generation delivery vectors for nucleic acid delivery.

Dual peptides-modified cationic liposomes for enhanced Lung cancer gene therapy by a gap junction regulating strategy

BACKGROUND

Gene therapy for lung cancer has emerged as a novel tumor-combating strategy for its superior tumor specificity, low systematical toxicity and huge clinical translation potential. Especially, the applications of microRNA shed led on effective tumor ablation by directly interfering with the crucial gene expression, making it one of the most promising gene therapy agents. However, for lung cancer therapy, the microRNA treatment confronted three bottlenecks, the poor tumor tissue penetration effect, the insufficient lung drug accumulation and unsatisfied gene transfection efficiency. To address these issues, an inhalable RGD-TAT dual peptides-modified cationic liposomes loaded with microRNA miR-34a and gap junction (GJ) regulation agent all-trans retinoic acid (ATRA) was proposed, which was further engineered into dry powder inhalers (DPIs).

RESULTS

Equipped with a rough particle surface and appropriate aerodynamic size, the proposed RGD-TAT-CLPs/ARTA@miR-34a DPIs were expected to deposit into the deep lung and reach lung tumor lesions guided by targeting peptide RGD. Assisted by cellular transmembrane peptides TAT, the RGD-TAT-CLPs/ARTA@miR-34a was proven to be effectively internalized by cancer cells, enhancing gene transfection efficiency. Then, the GJ between tumor cells was upregulated by ARTA, facilitating the intercellular transport of miR-34a and boosting the gene expression in the deep tumor.

CONCLUSION

Overall, the proposed RGD-TAT-CLPs/ARTA@miR-34a DPIs could enhance tumor tissue penetration, elevate lung drug accumulation and boost gene transfection efficiency, breaking the three bottlenecks to enhancing tumor elimination in vitro and in vivo. We believe that the proposed RGD-TAT-CLPs/ARTA@miR-34a DPIs could serve as a promising pulmonary gene delivery platform for multiple lung local disease treatments.

Inhaled RNA drugs to treat lung diseases: Disease-related cells and nano-bio interactions

In recent years, RNA-based therapies have gained much attention as biomedicines due to their remarkable therapeutic effects with high specificity and potency. Lung diseases offer a variety of currently undruggable but attractive targets that could potentially be treated with RNA drugs. Inhaled RNA drugs for the treatment of lung diseases, including asthma, chronic obstructive pulmonary disease, cystic fibrosis, and acute respiratory distress syndrome, have attracted more and more attention. A variety of novel nanoformulations have been designed and attempted for the delivery of RNA drugs to the lung via inhalation. However, the delivery of RNA drugs via inhalation poses several challenges. It includes protection of the stability of RNA molecules, overcoming biological barriers such as mucus and cell membrane to the delivery of RNA molecules to the targeted cytoplasm, escaping endosomal entrapment, and circumventing unwanted immune response etc. To address these challenges, ongoing researches focus on developing innovative nanoparticles to enhance the stability of RNA molecules, improve cellular targeting, enhance cellular uptake and endosomal escape to achieve precise delivery of RNA drugs to the intended lung cells while avoiding unwanted nano-bio interactions and off-target effects. The present review first addresses the pathologic hallmarks of different lung diseases, disease-related cell types in the lung, and promising therapeutic targets in these lung cells. Subsequently we highlight the importance of the nano-bio interactions in the lung that need to be addressed to realize disease-related cell-specific delivery of inhaled RNA drugs. This is followed by a review on the physical and chemical characteristics of inhaled nanoformulations that influence the nano-bio interactions with a focus on surface functionalization. Finally, the challenges in the development of inhaled nanomedicines and some key aspects that need to be considered in the development of future inhaled RNA drugs are discussed.

Lipid Nanoparticle (LNP) Enables mRNA Delivery for Cancer Therapy

Messenger RNA (mRNA) has received great attention in the prevention and treatment of various diseases due to the success of coronavirus disease 2019 (COVID-19) mRNA vaccines (Comirnaty and Spikevax). To meet the therapeutic purpose, it is required that mRNA must enter the target cells and express sufficient proteins. Therefore, the development of effective delivery systems is necessary and crucial. Lipid nanoparticle (LNP) represents a remarkable vehicle that has indeed accelerated mRNA applications in humans, as several mRNA-based therapies have already been approved or are in clinical trials. In this review, the focus is on mRNA-LNP-mediated anticancer therapy. It summarizes the main development strategies of mRNA-LNP formulations, discusses representative therapeutic approaches in cancer, and points out current challenges and possible future directions of this research field. It is hoped that these delivered messages can help further improve the application of mRNA-LNP technology in cancer therapy.

Hybrid mRNA Nano Vaccine Potentiates Antigenic Peptide Presentation and Dendritic Cell Maturation for Effective Cancer Vaccine Therapy and Enhances Response to Immune Checkpoint Blockade

Cancer vaccines combined with immune checkpoint blockades (ICB) represent great potential application, yet the insufficient tumor antigen presentation and immature dendritic cells hinder improved efficacy. Here, a hybrid nano vaccine composed by hyper branched poly(beta-amino ester), modified iron oxide nano adjuvant and messenger RNA (mRNA) encoded with model antigen ovalbumin (OVA) is presented. The nano vaccine outperforms three commercialized reagents loaded with the same mRNA, including Lipofectamine MessengerMax, jetPRIME, and in vivo-jetRNA in promoting dendritic cells' transfection, maturation, and peptide presentation. In an OVA-expressing murine model, intratumoral administration of the nano vaccine significantly induced macrophages and dendritic cells' presenting peptides and expressing co-stimulatory CD86. The nano vaccine also elicited strong antigen-specific splenocyte response and promoted CD8+ T cell infiltration. In combination with ICB, the nano vaccine aroused robust tumor suppression in murine models with large tumor burdens (initial volume >300 mm3 ). The hybrid mRNA vaccine represents a versatile and readily transformable platform and augments response to ICB.

Unlocking the potential of RNA-based therapeutics in the lung: current status and future directions

Awareness of RNA-based therapies has increased after the widespread adoption of mRNA vaccines against SARS-CoV-2 during the COVID-19 pandemic. These mRNA vaccines had a significant impact on reducing lung disease and mortality. They highlighted the potential for rapid development of RNA-based therapies and advances in nanoparticle delivery systems. Along with the rapid advancement in RNA biology, including the description of noncoding RNAs as major products of the genome, this success presents an opportunity to highlight the potential of RNA as a therapeutic modality. Here, we review the expanding compendium of RNA-based therapies, their mechanisms of action and examples of application in the lung. The airways provide a convenient conduit for drug delivery to the lungs with decreased systemic exposure. This review will also describe other delivery methods, including local delivery to the pleura and delivery vehicles that can target the lung after systemic administration, each providing access options that are advantageous for a specific application. We present clinical trials of RNA-based therapy in lung disease and potential areas for future directions. This review aims to provide an overview that will bring together researchers and clinicians to advance this burgeoning field.

Lung SORT LNPs enable precise homology-directed repair mediated CRISPR/Cas genome correction in cystic fibrosis models

Approximately 10% of Cystic Fibrosis (CF) patients, particularly those with CF transmembrane conductance regulator (CFTR) gene nonsense mutations, lack effective treatments. The potential of gene correction therapy through delivery of the CRISPR/Cas system to CF-relevant organs/cells is hindered by the lack of efficient genome editor delivery carriers. Herein, we report improved Lung Selective Organ Targeting Lipid Nanoparticles (SORT LNPs) for efficient delivery of Cas9 mRNA, sgRNA, and donor ssDNA templates, enabling precise homology-directed repair-mediated gene correction in CF models. Optimized Lung SORT LNPs deliver mRNA to lung basal cells in Ai9 reporter mice. SORT LNP treatment successfully corrected the CFTR mutations in homozygous G542X mice and in patient-derived human bronchial epithelial cells with homozygous F508del mutations, leading to the restoration of CFTR protein expression and chloride transport function. This proof-of-concept study will contribute to accelerating the clinical development of mRNA LNPs for CF treatment through CRISPR/Cas gene correction.

Cellular Trafficking of Nanotechnology-Mediated mRNA Delivery

Messenger RNA (mRNA)-based therapy has emerged as a powerful, safe, and rapidly scalable therapeutic approach that involves technologies for both mRNA itself and the delivery vehicle. Although there are some unique challenges for different applications of mRNA therapy, a common challenge for all mRNA therapeutics is the transport of mRNA into the target cell cytoplasm for sufficient protein expression. This review is focused on the behaviors at the cellular level of nanotechnology-mediated mRNA delivery systems, which have not been comprehensively reviewed yet. First, the four main therapeutic applications of mRNA are introduced, including immunotherapy, protein replacement therapy, genome editing, and cellular reprogramming. Second, common types of mRNA cargos and mRNA delivery systems are summarized. Third, strategies to enhance mRNA delivery efficiency during the cellular trafficking process are highlighted, including accumulation to the cell, internalization into the cell, endosomal escape, release of mRNA from the nanocarrier, and translation of mRNA into protein. Finally, the challenges and opportunities for the development of nanotechnology-mediated mRNA delivery systems are presented. This review can provide new insights into the future fabrication of mRNA nanocarriers with desirable cellular trafficking performance.

Novel Vectors and Administrations for mRNA Delivery

mRNA therapy has shown great potential in infectious disease vaccines, cancer immunotherapy, protein replacement therapy, gene editing, and other fields due to its central role in all life processes. However, mRNA is challenging to pass through the cell membrane due to its significant negative charges and degradation from RNase, so the key to mRNA therapy is efficient packaging and delivery of it with appropriate vectors. Presently researchers have developed various vectors such as viruses and liposomes, but these conventional vectors are now difficult to meet the growing requirement like safety, efficiency, and targeting, so many novel delivery vectors with unique advantages have emerged recently. This review mainly introduces two categories of novel vectors: biomacromolecules and inorganic nanoparticles, as well as two novel methods of control and administration based on these novel vectors: controlled-release administration and non-invasive administration. These novel delivery strategies have the advantages of high safety, biocompatibility, versatility, intelligence, and targeting. This paper analyzes the challenges faced by the field of mRNA delivery in depth, and discusses how to use the characteristics of novel vectors and administrations to solve these problems.

Drug delivery systems for CRISPR-based genome editors

CRISPR-based drugs can theoretically manipulate any genetic target. In practice, however, these drugs must enter the desired cell without eliciting an unwanted immune response, so a delivery system is often required. Here, we review drug delivery systems for CRISPR-based genome editors, focusing on adeno-associated viruses and lipid nanoparticles. After describing how these systems are engineered and their subsequent characterization in preclinical animal models, we highlight data from recent clinical trials. Preclinical targeting mediated by polymers, proteins, including virus-like particles, and other vehicles that may deliver CRISPR systems in the future is also discussed.

Inhaled mRNA nanoparticles dual-targeting cancer cells and macrophages in the lung for effective transfection

Messenger RNA (mRNA)-based therapeutics are transforming the landscapes of medicine, yet targeted delivery of mRNA to specific cell types while minimizing off-target accumulation remains challenging for mRNA-mediated therapy. In this study, we report an innovative design of a cationic lipid- and hyaluronic acid-based, dual-targeted mRNA nanoformulation that can display the desirable stability and efficiently transfect the targeted proteins into lung tissues. More importantly, the optimized dual-targeted mRNA nanoparticles (NPs) can not only accumulate primarily in lung tumor cells and inflammatory macrophages after inhalation delivery but also efficiently express any desirable proteins (e.g., p53 tumor suppressor for therapy, as well as luciferase and green fluorescence protein for imaging as examples in this study) and achieve efficacious lung tissue transfection in vivo. Overall, our findings provide proof-of-principle evidence for the design and use of dual-targeted mRNA NPs in homing to specific cell types to up-regulate target proteins in lung tissues, which may hold great potential for the future development of mRNA-based inhaled medicines or vaccines in treating various lung-related diseases.

RNA Nanomedicine: Delivery Strategies and Applications

Delivery of RNA using nanomaterials has emerged as a new modality to expand therapeutic applications in biomedical research. However, the delivery of RNA presents unique challenges due to its susceptibility to degradation and the requirement for efficient intracellular delivery. The integration of nanotechnologies with RNA delivery has addressed many of these challenges. In this review, we discuss different strategies employed in the design and development of nanomaterials for RNA delivery. We also highlight recent advances in the pharmaceutical applications of RNA delivered via nanomaterials. Various nanomaterials, such as lipids, polymers, peptides, nucleic acids, and inorganic nanomaterials, have been utilized for delivering functional RNAs, including messenger RNA (mRNA), small interfering RNA, single guide RNA, and microRNA. Furthermore, the utilization of nanomaterials has expanded the applications of functional RNA as active pharmaceutical ingredients. For instance, the delivery of antigen-encoding mRNA using nanomaterials enables the transient expression of vaccine antigens, leading to immunogenicity and prevention against infectious diseases. Additionally, nanomaterial-mediated RNA delivery has been investigated for engineering cells to express exogenous functional proteins. Nanomaterials have also been employed for co-delivering single guide RNA and mRNA to facilitate gene editing of genetic diseases. Apart from the progress made in RNA medicine, we discuss the current challenges and future directions in this field.

Charge-shifting polyplex as a viral RNA extraction carrier for streamlined detection of infectious viruses

The recent outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted the need for rapid, user-friendly nucleic acid testing that involves simple but efficient RNA extraction. Here, we present a charge-shifting polyplex as an RNA extraction carrier for advanced diagnosis of infectious viral diseases. The polyplex comprises poly(2-(dimethylamino) ethyl acrylate) (pDMAEA) electrostatically conjugated with RNA. The pDMAEA film can rapidly dissolve in the viral RNA solution, promoting immediate binding with RNA to form the polyplex, which enables the efficient capture of a substantial quantity of RNA. Subsequently, the captured RNA can be readily released by the quick hydrolysis of pDMAEA at the onset of quantitative reverse transcription-polymerase chain reaction (qRT-PCR), streamlining the entire process from RNA extraction to analysis. The developed method requires only 5 min of centrifugation and enables the detection of RNA in a one-pot setup. Moreover, the proposed method is fully compatible with high-speed qRT-PCR kits and can identify clinical samples within 1 h including the entire extraction to detection procedure. Indeed, the method successfully detected influenza viruses, SARS-CoV-2, and their delta and omicron variants in 260 clinical samples with a sensitivity of 99.4% and specificity of 98.9%. This rapid, user-friendly polyplex-based approach represents a significant breakthrough in molecular diagnostics.

Black Phosphorus Nanosheets Assist Nanoerythrosomes for Efficient mRNA Vaccine Delivery and Immune Activation

Messenger RNA (mRNA)-based vaccines have enormous potential in infectious disease prevention and tumor neoantigen application. However, developing an advanced delivery system for efficient mRNA delivery and intracellular release for protein translation remains a challenge. Herein, a biocompatible biomimetic system is designed using red blood cell-derived nanoerythrosomes (NER) and black phosphorus nanosheets (BP) for mRNA delivery. BP is covalently modified with polyethyleneimine (PEI), serving as a core to efficiently condense mRNA via electrostatic interactions. To facilitate the spleen targeting of the mRNA-loaded BP (BPmRNA ), NER is co-extruded with BPmRNA to construct a stable "core-shell" nanovaccine (NER@BPmRNA ). The mRNA nanovaccine exhibits efficient protein expression and immune activation via BP-mediated adjuvant effect and enhanced lysosomal escape. In vivo evaluation demonstrates that the system delivery of mRNA encoding coronavirus receptor-binding domain (RBD) significantly increases the antibody titer and pseudovirus neutralization effect compared with that of NER without BP assistance. Furthermore, the mRNA extracted from mouse melanoma tissues is utilized to simulate tumor neoantigen delivered by NER@BPmRNA . In the vaccinated mice, BP-assisted NER for the delivery of melanoma mRNA can induce more antibodies that specifically recognize tumor antigens. Thus, BP-assisted NER can serve as a safe and effective delivery vehicle in mRNA-based therapy.

Combinatorial design of nanoparticles for pulmonary mRNA delivery and genome editing

The expanding applications of nonviral genomic medicines in the lung remain restricted by delivery challenges. Here, leveraging a high-throughput platform, we synthesize and screen a combinatorial library of biodegradable ionizable lipids to build inhalable delivery vehicles for messenger RNA and CRISPR-Cas9 gene editors. Lead lipid nanoparticles are amenable for repeated intratracheal dosing and could achieve efficient gene editing in lung epithelium, providing avenues for gene therapy of congenital lung diseases.