Nanoplatforms for mRNA Therapeutics

Recent developments with pH-responsive lyotropic liquid crystalline lipid nanoparticles for targeted bioactive agent delivery

INTRODUCTION

Lyotropic liquid crystalline lipid nanoparticles (LNPs) are a platform technology with broad-ranging potential in bioactive agent delivery applications. Their biomimetic properties impart the capacity to encapsulate large biomolecules and to overcome traditional biological barriers.

AREAS COVERED

The properties of lyotropic liquid crystalline LNPs can vary significantly between phases. We briefly introduce key concepts related to their formation and self-assembly and how ionization at the lipid-water interface, i.e. pH-responsiveness, can be leveraged to alter the properties of the nanoparticles. In this review, we summarize recent advances mainly from the past five years that highlight the role and impact of incorporating ionizable lipids, copolymers, and drug molecules in pH-responsive nanocarriers for the delivery of bioactive agents.

EXPERT OPINION

The development of pH-responsive lipid nanoparticles (pR_LNPs) is at the forefront of the new wave of mRNA therapeutics. The complexity of the biological journey faced by the nanoparticle and the broad spectrum of disease targets is sparking a surge in research activity. The accelerating development of new ionizable lipid materials to enhance mRNA delivery potential may benefit from closer consideration - or in tandem development - of self-assembly, interface ionization, and artificial intelligence integration.

Comparative Function Analysis of Self-Amplifying mRNA and Self-Amplifying DNA

A promising approach to address the transient translation mRNA drugs is the development of self-amplifying mRNA (SAM). Similarly, SAM's DNA template, self-amplifying DNA (SAD), can also play a role in self-amplifying the target mRNA. However, there is still a lack of sufficient valid information on the comparative analysis of SAM and SAD. Therefore, various vectors and delivery systems are selected to compare and analyze the transfection efficiency of SAM and SAD, and transfection conditions for SAM are optimized. It is found that SAD and SAM have obviously different preferences in transfection conditions, and there is also a gap in their transfection efficiencies under the same conditions. Furthermore, the optimal transfection dose of SAD and SAM and the optimal incubation time after transfection are also determined. This study provides valuable information on SAM transfection and its difference with SAD, and offers an option of selecting appropriate nucleic acid vectors for drug development.

More than a delivery system: the evolving role of lipid-based nanoparticles

Lipid-based nanoparticles, including liposomes and lipid nanoparticles (LNPs), make up an important class of drug delivery systems. Their modularity enables encapsulation of a wide range of therapeutic cargoes, their ease of functionalization allows for incorporation of targeting motifs and anti-fouling coatings, and their scalability facilitates rapid translation to the clinic. While the discovery and early understanding of lipid-based nanoparticles is heavily rooted in biology, formulation development has largely focused on materials properties, such as how liposome and lipid nanoparticle composition can be altered to maximize drug loading, stability and circulation. To achieve targeted delivery and enable improved accumulation of therapeutics at target tissues or disease sites, emphasis is typically placed on the use of external modifications, such as peptide, protein, and polymer motifs. However, these approaches can increase the complexity of the nanocarrier and complicate scale up. In this review, we focus on how our understanding of lipid structure and function in biological contexts can be used to design intrinsically functional and targeted nanocarriers. We highlight formulation-based strategies, such as the incorporation of bioactive lipids, that have been used to modulate liposome and lipid nanoparticle properties and improve their functionality while retaining simple nanocarrier designs. We also highlight classes of naturally occurring lipids, their functions, and how they have been incorporated into lipid-based nanoparticles. We will additionally position these approaches into the historical context of both liposome and LNP development.

A Review on the Stability Challenges of Advanced Biologic Therapeutics

Advanced biotherapeutic systems such as gene therapy, mRNA lipid nanoparticles, antibody-drug conjugates, fusion proteins, and cell therapy have proven to be promising platforms for delivering targeted biologic therapeutics. Preserving the intrinsic stability of these advanced therapeutics is essential to maintain their innate structure, functionality, and shelf life. Nevertheless, various challenges and obstacles arise during formulation development and throughout the storage period due to their complex nature and sensitivity to various stress factors. Key stability concerns include physical degradation and chemical instability due to various factors such as fluctuations in pH and temperature, which results in conformational and colloidal instabilities of the biologics, adversely affecting their quality and therapeutic efficacy. This review emphasizes key stability issues associated with these advanced biotherapeutic systems and approaches to identify and overcome them. In gene therapy, the brittleness of viral vectors and gene encapsulation limits their stability, requiring the use of stabilizers, excipients, and lyophilization. Keeping cells viable throughout the whole cell therapy process, from culture to final formulation, is still a major difficulty. In mRNA therapeutics, stabilization strategies such as the optimization of mRNA nucleotides and lipid compositions are used to address the instability of both the mRNA and lipid nanoparticles. Monoclonal antibodies are colloidally and conformationally unstable. Hence, buffers and stabilizers are useful to maintain stability. Although fusion proteins and monoclonal antibodies share structural similarities, they show a similar pattern of instability. Antibody-drug conjugates possess issues with conjugation and linker stability. This review outlines the stability issues associated with advanced biotherapeutics and provides insights into the approaches to address these challenges.

Current Trends in Messenger RNA Technology for Cancer Therapeutics

Messenger RNA (mRNA)-based therapy has revolutionized cancer research by enabling versatile delivery systems for therapeutic applications. The future of mRNA-based cancer therapies shows promise amidst challenges such as delivery efficiency, immunogenicity, and tumor heterogeneity. Recent progress has adapted various strategies such as design flexibility, scalable production, and targeted delivery capabilities to enhance the potential in personalized cancer therapy. Further research to optimize delivery for enhanced outcomes and efficacy in solid tumors is warranted. Therefore, we aim to explore the current landscape and future prospects of mRNA technology across various therapeutic platforms.

Chirality-Controlled Lipid Nanoparticles for mRNA Delivery

mRNA therapeutics present a promising strategy for the treatment of human diseases, which requires a carrier to protect the mRNA and ensure its effective cellular delivery. However, research on how the surface physicochemical properties of the mRNA carriers affect the efficiency of delivery of mRNA into cells has been limited thus far. Here, we report that chirality control of lipid nanoparticles (LNPs) can enhance the delivery and transfection efficiency of cargo mRNA into cells. We prepared chiral LNPs by surface modification of LNPs with chiral cobalt oxide nanoparticles. The chiral LNPs with d- or l-chirality resulted in different cellular uptake and transfection efficiencies of luciferase or EGFP mRNA. Chiral LNPs with d-chirality showed significant enhancement in cellular delivery as well as transfection (5.3-fold) of mRNA compared to the control LNPs. This study suggests a novel strategy of using chirality for the delivery of nucleic acid drugs and provides a more in-depth understanding of the effect of chirality on cells.

Advances in RNAi-based nanoformulations: revolutionizing crop protection and stress tolerance in agriculture

Nucleic acid-based therapeutics have the ability to tackle a wide range of diseases and stress tolerance that present significant obstacles for conventional approaches in agriculture. RNA-based medicines have become a promising approach, using nanoformulation treatments to specifically target certain diseases. Nanoformulations offer numerous benefits in comparison to alternative treatment methods, such as precise administration, minimal toxicity, and medication loading compatibility due to their bioactivity. There are a variety of nanoformulations available today, such as liposomes, polymeric nanoparticles (NPs), magnetic NPs, nanogels, and solid lipid nanoparticles (SLNs). RNA-based therapy employs intracellular gene nanoparticles containing messenger RNA (mRNA), which play an important role in stress management and pest as well as disease control. The adoption of mRNA-based technology paves the way for future technological progress. This review focuses on elucidating the process underlying the development of RNA interference (RNAi) and the diverse array of nanocarriers employed for the transportation of RNAi. Currently, this technique is being employed in the field of crop protection to combat diseases, pests, and environmental stress. The article highlights the benefits of RNAi mediated nanoformulations and discusses the significant obstacles that must be overcome to improve the viability of this technology for future applications.

Lipid Nanoparticles for mRNA Delivery in Cancer Immunotherapy

Cancer immunotherapy is poised to be one of the major modalities for cancer treatment. Messenger RNA (mRNA) has emerged as a versatile and promising platform for the development of effective cancer immunotherapy. Delivery systems for mRNA therapeutics are pivotal for their optimal therapeutic efficacy and minimal adverse side effects. Lipid nanoparticles (LNPs) have demonstrated a great success for mRNA delivery. Numerous LNPs have been designed and optimized to enhance mRNA stability, facilitate transfection, and ensure intracellular delivery for subsequent processing. Nevertheless, challenges remain to, for example, improve the efficiency of endosomal escape and passive targeting. This review highlights key advancements in the development of mRNA LNPs for cancer immunotherapy. We delve into the design of LNPs for mRNA delivery, encompassing the chemical structures, characterization, and structure-activity relationships (SAR) of LNP compositions. We discuss the key factors influencing the transfection efficiency, passive targeting, and tropism of mRNA-loaded LNPs. We also review the preclinical and clinical applications of mRNA LNPs in cancer immunotherapy. This review can enhance our understanding in the design and application of LNPs for mRNA delivery in cancer immunotherapy.

Ionizable Lipids with Branched Linkers Enhance the Delivery of mRNA Vaccines

The emergence of mRNA vaccines has heralded an epoch in disease prevention and treatment. Safe and efficient mRNA delivery systems are highly desired for the widespread application of mRNA therapeutics. Herein, we have designed a facile synthetic pathway for producing ionizable lipids featuring various branched linkers. These lipids have been integrated into lipid nanoparticles (LNPs) to improve the delivery of mRNA vaccines. The influence of linker structure on lipids and LNPs is currently underreported, yet it undeniably exerts a substantial impact on the outcomes. Through systematic screening and formulation optimization, we have identified that LNPs comprising ionizable lipids with a branched β-isobutylglutarate linker (bLNPs) exhibited superior transfection capabilities. In preclinical cancer prevention and treatment models, mRNA vaccines delivered by bLNPs (mRNA-bLNPs) have shown significant efficacy without causing systemic toxicity, highlighting the potential of bLNPs for clinical translation. Our synthetic strategy facilitates the expansion of the LNP library and provides valuable insights into the relationship between linker structures and delivery efficiency, thereby propelling the advancement of LNP technology.

A review of RNA nanoparticles for drug/gene/protein delivery in advanced therapies: Current state and future prospects

Nanotechnology involves the utilization of materials with exceptional properties at the nanoscale. Over the past few years, nanotechnologies have demonstrated significant potential in improving human health, particularly in medical treatments. The self-assembly characteristic of RNA is a highly effective method for designing and constructing nanostructures using a combination of biological, chemical, and physical techniques from different fields. There is great potential for the application of RNA nanotechnology in therapeutics. This review explores various nano-based drug delivery systems and their unique features through the impressive progress of the RNA field and their significant therapeutic promises due to their unique performance in the COVID-19 pandemic. However, a significant hurdle in fully harnessing the power of RNA drugs lies in effectively delivering RNA to precise organs and tissues, a critical factor for achieving therapeutic effectiveness, minimizing side effects, and optimizing treatment outcomes. There have been many efforts to pursue targeting, but the clinical translation of RNA drugs has been hindered by the lack of clear guidelines and shared understanding. A comprehensive understanding of various principles is essential to develop vaccines using nucleic acids and nanomedicine successfully. These include mechanisms of immune responses, functions of nucleic acids, nanotechnology, and vaccinations. Regarding this matter, the aim of this review is to revisit the fundamental principles of the immune system's function, vaccination, nanotechnology, and drug delivery in relation to the creation and manufacturing of vaccines utilizing nanotechnology and nucleic acids. RNA drugs have demonstrated significant potential in treating a wide range of diseases in both clinical and preclinical research. One of the reasons is their capacity to regulate gene expression and manage protein production efficiently. Different methods, like modifying chemicals, connecting ligands, and utilizing nanotechnology, have been essential in enabling the effective use of RNA-based treatments in medical environments. The article reviews stimuli-responsive nanotechnologies for RNA delivery and their potential in RNA medicines. It emphasizes the notable benefits of these technologies in improving the effectiveness of RNA and targeting specific cells and organs. This review offers a comprehensive analysis of different RNA drugs and how they work to produce therapeutic benefits. Recent progress in using RNA-based drugs, especially mRNA treatments, has shown that targeted delivery methods work well in medical treatments.

Dual-Mechanism mRNA Delivery via Fluorinated-Sorbitol Polyplexes: Enhancing Cellular Uptake and Endosomal Escape for COVID-19 Vaccination

Advancements in mRNA delivery nanoparticles have significantly improved the potential for treating challenging diseases. Due to the inherent immunogenicity and rapid degradation of mRNA, specialized nanoparticles are required for efficient intracellular uptake, endosomal escape, and protection from lysosomal degradation. Although current methods enable transgene expression but achieving a balance between efficiency and toxicity remains challenging. In this study, an effective mRNA delivery system is developed by modifying a cationic polymer with sorbitol and fluorine, resulting in fluorinated polyethyleneimine with sorbitol functionalization (PFS). This polyplex enhances mRNA delivery through improved cellular uptake via sorbitol channels and caveolae-mediated endocytosis, while fluorination facilitates endosomal escape and mitigates toxicity. The formulation demonstrated successful expression of Gaussian luciferase mRNA in both Raw 264.7 cells and Balb/c mice. Additionally, intramuscular administration of the SARS-CoV-2 spike mRNA vaccine elicited robust immune responses comparable to Moderna's LNP formulation. The vaccine effectively neutralized the Wuhan variant strain of SARS-CoV-2, as shown by PRNT50 testing. These findings suggest that the PFS formulation is a promising candidate for developing polymeric mRNA vaccines targeting various infectious and non-infectious diseases.

Bioengineered Nanomaterials for siRNA Therapy of Chemoresistant Cancers

Chemoresistance remains a long-standing challenge after cancer treatment. Over the last two decades, RNA interference (RNAi) has emerged as a gene therapy modality to sensitize cancer cells to chemotherapy. However, the use of RNAi, specifically small-interfering RNA (siRNA), is hindered by biological barriers that limit its intracellular delivery. Nanoparticles can overcome these barriers by protecting siRNA in physiological environments and facilitating its delivery to cancer cells. In this review, we discuss the development of nanomaterials for siRNA delivery in cancer therapy, current challenges, and future perspectives for their implementation to overcome cancer chemoresistance.

Navigating the intricate in-vivo journey of lipid nanoparticles tailored for the targeted delivery of RNA therapeutics: a quality-by-design approach

RNA therapeutics, such as mRNA, siRNA, and CRISPR-Cas9, present exciting avenues for treating diverse diseases. However, their potential is commonly hindered by vulnerability to degradation and poor cellular uptake, requiring effective delivery systems. Lipid nanoparticles (LNPs) have emerged as a leading choice for in vivo RNA delivery, offering protection against degradation, enhanced cellular uptake, and facilitation of endosomal escape. However, LNPs encounter numerous challenges for targeted RNA delivery in vivo, demanding advanced particle engineering, surface functionalization with targeting ligands, and a profound comprehension of the biological milieu in which they function. This review explores the structural and physicochemical characteristics of LNPs, in-vivo fate, and customization for RNA therapeutics. We highlight the quality-by-design (QbD) approach for targeted delivery beyond the liver, focusing on biodistribution, immunogenicity, and toxicity. In addition, we explored the current challenges and strategies associated with LNPs for in-vivo RNA delivery, such as ensuring repeated-dose efficacy, safety, and tissue-specific gene delivery. Furthermore, we provide insights into the current clinical applications in various classes of diseases and finally prospects of LNPs in RNA therapeutics.

Enhanced Delivery and Potency of Chemotherapeutics in Melanoma Treatment via Magnetite Nanobioconjugates

Melanoma, known for its aggressive metastatic potential, poses significant treatment challenges. Despite the potent antiproliferative effects of anticancer drugs, systemic toxicity and low water solubility limit their efficacy. This study addresses these challenges by employing magnetite (Fe3O4) nanobioconjugates as a drug delivery system, aimed at enhancing drug solubility and reducing off-target effects in melanoma therapy. Magnetite nanoparticles (MNPs) were engineered with functional molecules and loaded with the anticancer agents Temozolomide (TMZ) or paclitaxel (PTX). The nanobioconjugates were characterized via Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and transmission electron microscopy (TEM). The results validated the efficacious synthesis and drug loading, attaining efficiencies ranging from 32 to 72% for TMZ and 32 to 60% for PTX. Biocompatibility assessments demonstrated excellent tolerance, with minimal hemolysis rates and platelet aggregation. In vitro studies revealed enhanced cytotoxicity against A-375 human melanoma cells compared to free drugs, with cellular uptake facilitated primarily through macropinocytosis, caveolin-, and clathrin-mediated endocytosis. Furthermore, the nanobioconjugates exhibited significant efficacy in targeting A-375 melanoma spheroids, underlining their potential in melanoma therapy. This research underscores magnetite nanobioconjugates as a promising avenue for targeted melanoma treatment, offering enhanced drug delivery specificity and reduced systemic toxicity in oncological drug delivery systems.

Better, Faster, Stronger: Accelerating mRNA-Based Immunotherapies With Nanocarriers

Messenger ribonucleic acid (mRNA) therapeutics are attracting attention as promising tools in cancer immunotherapy due to their ability to leverage the in vivo expression of all known protein sequences. Even small amounts of mRNA can have a powerful effect on cancer vaccines by promoting the synthesis of tumor-specific antigens (TSA) or tumor-associated antigens (TAA) by antigen-presenting cells (APC). These antigens are then presented to T cells, eliciting strong antitumor immune stimulation. The potential of mRNA can be further enhanced by expressing immunomodulatory agents, such as cytokines, antibodies, and chimeric antigen receptors (CAR), enhancing tumor immunity. Recent research also explores mRNA-encoded tumor death inducers or tumor microenvironment (TME) modulators. Despite its promise, the clinical translation of mRNA-based anticancer strategies faces challenges, including inefficient targeted delivery in vivo, failure of endosomal escape, and inadequate intracellular mRNA release, resulting in poor transfection efficiencies. Inspired by the approval of lipid nanoparticle-loaded mRNA vaccines against coronavirus disease 2019 (COVID-19) and the encouraging outcomes of mRNA-based cancer therapies in trials, innovative nonviral nanotechnology delivery systems have been engineered. These aim to advance mRNA-based cancer immunotherapies from research to clinical application. This review summarizes recent preclinical and clinical progress in lipid and polymeric nanomedicines for delivering mRNA-encoded antitumor therapeutics, including cytokines and antibody-based immunotherapies, cancer vaccines, and CAR therapies. It also addresses advanced delivery systems for direct oncolysis or TME reprogramming and highlights key challenges in translating these therapies to clinical use, exploring future perspectives, including the role of artificial intelligence and machine learning in their development.

Development of mRNA Lipid Nanoparticles: Targeting and Therapeutic Aspects

Lipid nanoparticles (LNPs) have emerged as leading non-viral carriers for messenger RNA (mRNA) delivery in clinical applications. Overcoming challenges in safe and effective mRNA delivery to target tissues and cells, along with controlling release from the delivery vehicle, remains pivotal in mRNA-based therapies. This review elucidates the structure of LNPs, the mechanism for mRNA delivery, and the targeted delivery of LNPs to various cells and tissues, including leukocytes, T-cells, dendritic cells, Kupffer cells, hepatic endothelial cells, and hepatic and extrahepatic tissues. Here, we discuss the applications of mRNA-LNP vaccines for the prevention of infectious diseases and for the treatment of cancer and various genetic diseases. Although challenges remain in terms of delivery efficiency, specific tissue targeting, toxicity, and storage stability, mRNA-LNP technology holds extensive potential for the treatment of diseases.

Low-Dose Mildronate-Derived Lipidoids for Efficient mRNA Vaccine Delivery with Minimal Inflammation Side Effects

mRNA vaccines have been revolutionizing disease prevention and treatment. However, their further application is hindered by inflammatory side effects, primarily caused by delivery systems such as lipid nanoparticles (LNPs). In response to this issue, we prepared cationic lipids (mLPs) derived from mildronate, a small-molecule drug, and subsequently developed the LNP (mLNP-69) comprising a low dose of mLP. Compared with the LNP (sLNP) based on SM-102, a commercially available ionizable lipid, mLNP-69 ensures effective mRNA delivery while significantly reducing local inflammation. In preclinical prophylactic and therapeutic B16-OVA melanoma models, mLNP-69 demonstrated successful mRNA cancer vaccine delivery in vivo, effectively preventing tumor occurrence or impeding tumor progression. The results suggest that the cationic lipids derived from mildronate, which exhibit efficient delivery capabilities and minimal inflammatory side effects, hold great promise for clinical application.

Advancing mRNA Therapeutics: The Role and Future of Nanoparticle Delivery Systems

The coronavirus (COVID-19) pandemic has underscored the critical role of mRNA-based vaccines as powerful, adaptable, readily manufacturable, and safe methodologies for prophylaxis. mRNA-based treatments are emerging as a hopeful avenue for a plethora of conditions, encompassing infectious diseases, cancer, autoimmune diseases, genetic diseases, and rare disorders. Nonetheless, the in vivo delivery of mRNA faces challenges due to its instability, suboptimal delivery, and potential for triggering undesired immune reactions. In this context, the development of effective drug delivery systems, particularly nanoparticles (NPs), is paramount. Tailored with biophysical and chemical properties and susceptible to surface customization, these NPs have demonstrated enhanced mRNA delivery in vivo and led to the approval of several NPs-based formulations for clinical use. Despite these advancements, the necessity for developing a refined, targeted NP delivery system remains imperative. This review comprehensively surveys the biological, translational, and clinical progress in NPs-mediated mRNA therapeutics for both the prevention and treatment of diverse diseases. By addressing critical factors for enhancing existing methodologies, it aims to inform the future development of precise and efficacious mRNA-based therapeutic interventions.

Thu H, Dobchev D, Balsubramani A, N.D. Santos R, Kogler-Anele L, Corrochano-Navarro A, Li S, U. Montoya F, Agarwal V, Bar-Joseph Z, Jager S. Representations of lipid nanoparticles using large language models for transfection efficiency prediction

MOTIVATION

Lipid nanoparticles (LNPs) are the most widely used vehicles for mRNA vaccine delivery. The structure of the lipids composing the LNPs can have a major impact on the effectiveness of the mRNA payload. Several properties should be optimized to improve delivery and expression including biodegradability, synthetic accessibility, and transfection efficiency.

RESULTS

To optimize LNPs, we developed and tested models that enable the virtual screening of LNPs with high transfection efficiency. Our best method uses the lipid Simplified Molecular-Input Line-Entry System (SMILES) as inputs to a large language model. Large language model-generated embeddings are then used by a downstream gradient-boosting classifier. As we show, our method can more accurately predict lipid properties, which could lead to higher efficiency and reduced experimental time and costs.

AVAILABILITY AND IMPLEMENTATION

Code and data links available at: https://github.com/Sanofi-Public/LipoBART.

A comprehensive comparison of DNA and RNA vaccines

Nucleic acid technology has revolutionized vaccine development, enabling rapid design and production of RNA and DNA vaccines for prevention and treatment of diseases. The successful deployment of mRNA and plasmid DNA vaccines against COVID-19 has further validated the technology. At present, mRNA platform is prevailing due to its higher efficacy, while DNA platform is undergoing rapid evolution because it possesses unique advantages that can potentially overcome the problems associated with the mRNA platform. To help understand the recent performances of the two vaccine platforms and recognize their clinical potentials in the future, this review compares the advantages and drawbacks of mRNA and DNA vaccines that are currently known in the literature, in terms of development timeline, financial cost, ease of distribution, efficacy, safety, and regulatory approval of products. Additionally, the review discusses the ongoing clinical trials, strategies for improvement, and alternative designs of RNA and DNA platforms for vaccination.

Cardiac delivery of modified mRNA using lipid nanoparticles: Cellular targets and biodistribution after intramyocardial administration

Despite research efforts being made towards preserving (or even regenerating) heart tissue after an ischemic event, there is a lack of resources in current clinical treatment modalities for patients with acute myocardial infarction that specifically address cardiac tissue impairment. Modified messenger RNA (modRNA) presents compelling properties that could allow new therapeutic strategies to tackle the underlying molecular pathways that ultimately lead to development of chronic heart failure. However, clinical application of modRNA for the heart is challenged by the lack of effective and safe delivery systems. Lipid nanoparticles (LNPs) represent a well characterized class of RNA delivery systems, which were recently approved for clinical usage in mRNA-based COVID-19 vaccines. In this study, we evaluated the potential of LNPs for cardiac delivery of modRNA. We tested how variations in C12-200 modRNA-LNP composition affect transfection levels and biodistribution after intramyocardial administration in both healthy and myocardial-infarcted mice, and determined the targeted cardiac cell types. Our data revealed that LNP-mediated modRNA delivery outperforms the current state of the art (modRNA in citrate buffer) upon intramyocardial administration in mice, with only minor differences among the formulations tested. Furthermore, we determined both in vitro and in vivo that the cardiac cells targeted by modRNA-LNPs include fibroblasts, endothelial cells and epicardial cells, suggesting that these cell types could represent targets for therapeutic interference with these LNP formulations. These outcomes may serve as a starting point for LNP development specifically for therapeutic mRNA cardiac delivery applications.

Unlocking the potential of nanocarrier-mediated mRNA delivery across diverse biomedical frontiers: A comprehensive review

Messenger RNA (mRNA) has gained marvelous attention for managing and preventing various conditions like cancer, Alzheimer's, infectious diseases, etc. Due to the quick development and success of the COVID-19 mRNA-based vaccines, mRNA has recently grown in prominence. A lot of products are in clinical trials and some are already FDA-approved. However, still improvements in line of optimizing stability and delivery, reducing immunogenicity, increasing efficiency, expanding therapeutic applications, scalability and manufacturing, and long-term safety monitoring are needed. The delivery of mRNA via a nanocarrier system gives a synergistic outcome for managing chronic and complicated conditions. The modified nanocarrier-loaded mRNA has excellent potential as a therapeutic strategy. This emerging platform covers a wide range of diseases, recently, several clinical studies are ongoing and numerous publications are coming out every year. Still, many unexplained physical, biological, and technical problems of mRNA for safer human consumption. These complications were addressed with various nanocarrier formulations. This review systematically summarizes the solved problems and applications of nanocarrier-based mRNA delivery. The modified nanocarrier mRNA meaningfully improved mRNA stability and abridged its immunogenicity issues. Furthermore, several strategies were discussed that can be an effective solution in the future for managing complicated diseases.

Optimizing Nucleic Acid Delivery Systems through Barcode Technology

Conventional biological experiments often focus on in vitro assays because of the inherent limitations when handling multiple variables in vivo, including labor-intensive and time-consuming procedures. Often only a subset of samples demonstrating significant efficacy in the in vitro assays can be evaluated in vivo. Nonetheless, because of the low correlation between the in vitro and in vivo tests, evaluation of the variables under examination in vivo and not solely in vitro is critical. An emerging approach to achieve high-throughput in vivo tests involves using a barcode system consisting of various nucleotide combinations. Unique barcodes for each variant enable the simultaneous testing of multiple entities, eliminating the need for separate individual tests. Subsequently, to identify crucial parameters, samples were collected and analyzed using barcode sequencing. This review explores the development of barcode design and its applications, including the evaluation of nucleic acid delivery systems and the optimization of gene expression in vivo.

Design and Characterization of a New Formulation for the Delivery of COVID-19-mRNA Vaccine to the Nasal Mucosa

Chitosan, a natural polysaccharide derived from chitin, possesses biocompatibility, biodegradability, and mucoadhesive characteristics, making it an attractive material for the delivery of mRNA payloads to the nasal mucosa and promoting their uptake by target cells such as epithelial and immune cells (e.g., dendritic cells and macrophages). In this project, we aimed at developing novel lipid-based nanoformulations for mRNA delivery to counteract the pandemic caused by SARS-CoV-2 virus. The formulations achieved a mRNA encapsulation efficiency of ~80.2% with chitosan-lipid nanoparticles, as measured by the RiboGreen assay. Furthermore, the evaluation of SARS-CoV-2 Spike (S) receptor-binding domain (RBD) expression via ELISA for our vaccine formulations showed transfection levels in human embryonic kidney cells (HEK 293), lung carcinoma cells (A549), and dendritic cells (DC 2.4) equal to 9.9 ± 0.1 ng/mL (174.7 ± 1.1 fold change from untreated cells (UT)), 7.0 ± 0.2 ng/mL (128.1 ± 4.9 fold change from UT), and 0.9 ± 0.0 ng/mL (18.0 ± 0.1 fold change from UT), respectively. Our most promising vaccine formulation was also demonstrated to be amenable to lyophilization with minimal degradation of loaded mRNA, paving the way towards a more accessible and stable vaccine. Preliminary in vivo studies in mice were performed to assess the systemic and local immune responses. Nasal bronchoalveolar lavage fluid (BALF) wash showed that utilizing the optimized formulation resulted in local antibody concentrations and did not trigger any systemic antibody response. However, if further improved and developed, it could potentially contribute to the management of COVID-19 through nasopharyngeal immunization strategies.

Advances in lipid nanoparticle mRNA therapeutics beyond COVID-19 vaccines

The remarkable success of two lipid nanoparticle-mRNA vaccines against coronavirus disease (COVID-19) has placed the therapeutic and prophylactic potential of messenger RNA (mRNA) in the spotlight. It has also drawn attention to the indispensable role of lipid nanoparticles in enabling the effects of this nucleic acid. To date, lipid nanoparticles are the most clinically advanced non-viral platforms for mRNA delivery. This is thanks to their favorable safety profile and efficiency in protecting the nucleic acid from degradation and allowing its cellular uptake and cytoplasmic release upon endosomal escape. Moreover, the development of lipid nanoparticle-mRNA therapeutics was already a very active area of research even before the COVID-19 pandemic, which has likely only begun to bear its fruits. In this Review, we first discuss key aspects of the development of lipid nanoparticles as mRNA carriers. We then highlight promising preclinical and clinical studies involving lipid nanoparticle-mRNA formulations against infectious diseases and cancer, and to enable protein replacement or supplementation and genome editing. Finally, we elaborate on the challenges in advancing lipid nanoparticle-mRNA technology to widespread therapeutic use.

mRNA delivery systems for cancer immunotherapy: Lipid nanoparticles and beyond

mRNA-based vaccines are emerging as a promising alternative to standard cancer treatments and the conventional vaccines. Moreover, the FDA-approval of three nucleic acid based therapeutics (Onpattro, BNT162b2 and mRNA-1273) has further increased the interest and trust on this type of therapeutics. In order to achieve a significant therapeutic efficacy, the mRNA needs from a drug delivery system. In the last years, several delivery platforms have been explored, being the lipid nanoparticles (LNPs) the most well characterized and studied. A better understanding on how mRNA-based therapeutics operate (both the mRNA itself and the drug delivery system) will help to further improve their efficacy and safety. In this review, we will provide an overview of what mRNA cancer vaccines are and their mode of action and we will highlight the advantages and challenges of the different delivery platforms that are under investigation.

Recent advances in mRNA-based vaccine for cancer therapy; bench to bedside

The messenger RNA (mRNA) vaccines have progressed from a theoretical concept to a clinical reality over the last few decades. Compared to conventional vaccination methods, these vaccines have a number of benefits, such as substantial potency, rapid growth, inexpensive production, and safe administration. Nevertheless, their usefulness was restricted up to now due to worries about the erratic and ineffective circulation of mRNA in vivo. Thankfully, these worries have largely been allayed by recent technological developments, which have led to the creation of multiple mRNA vaccination platforms for cancer and viral infections. The mRNA vaccines have been demonstrated as a powerful alternative to traditional conventional vaccines because of their high potency, safety and efficacy, capacity for rapid clinical development, and potential for rapid, low-cost manufacturing. The paper will examine the present status of mRNA vaccine technology and suggest future paths for the advancement and application of this exciting vaccine platform as a common therapeutic choice.

Correlating Stability-Indicating Biochemical and Biophysical Characteristics with In Vitro Cell Potency in mRNA LNP Vaccine

The development of mRNA vaccines has increased rapidly since the COVID-19 pandemic. As one of the critical attributes, understanding mRNA lipid nanoparticle (LNP) stability is critical in the vaccine product development. However, the correlation between LNPs' physiochemical characteristics and their potency still remains unclear. The lack of regulatory guidance on the specifications for mRNA LNPs is also partially due to this underexplored relationship. In this study, we performed a three-month stability study of heat-stressed mRNA LNP samples. The mRNA LNP samples were analyzed for their mRNA degradation, LNP particle sizes, and mRNA encapsulation efficiency. In vitro cell potency was also evaluated and correlated with these above-mentioned physiochemical characterizations. The mRNA degradation-cell potency correlation data showed two distinct regions, indicating a critical cut-off size limit for mRNA degradation. The same temperature dependence was also observed in the LNP size-cell potency correlation.

Chemistry and Art of Developing Lipid Nanoparticles for Biologics Delivery: Focus on Development and Scale-Up

Lipid nanoparticles (LNPs) have gained prominence as primary carriers for delivering a diverse array of therapeutic agents. Biological products have achieved a solid presence in clinical settings, and the anticipation of creating novel variants is increasing. These products predominantly encompass therapeutic proteins, nucleic acids and messenger RNA. The advancement of efficient LNP-based delivery systems for biologics that can overcome their limitations remains a highly favorable formulation strategy. Moreover, given their small size, biocompatibility, and biodegradation, LNPs can proficiently transport therapeutic moiety into the cells without significant toxicity and adverse reactions. This is especially crucial for the existing and upcoming biopharmaceuticals since large molecules as a group present several challenges that can be overcome by LNPs. This review describes the LNP technology for the delivery of biologics and summarizes the developments in the chemistry, manufacturing, and characterization of lipids used in the development of LNPs for biologics. Finally, we present a perspective on the potential opportunities and the current challenges pertaining to LNP technology.

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.

Telomerase mRNA Enhances Human Skin Engraftment for Wound Healing

Deep skin wounds represent a serious condition and frequently require split-thickness skin grafts (STSG) to heal. The application of autologous human-skin-cell-suspension (hSCS) requires less donor skin than STSG without compromising the healing capacity. Impaired function and replicative ability of senescent cutaneous cells in the aging skin affects healing with autologous hSCS. Major determinants of senescence are telomere erosion and DNA damage. Human telomerase reverse transcriptase (hTERT) adds telomeric repeats to the DNA and can protect against DNA damage. Herein, hTERT mRNA lipid nanoparticles (LNP) are proposed and evaluated for enhancing cellular engraftment and proliferation of hSCS. Transfection with optimized hTERT mRNA LNP system enables delivery and expression of mRNA in vitro in keratinocytes, fibroblasts, and in hSCS prepared from donors' skin. Telomerase activity in hSCS is significantly increased. hTERT mRNA LNP enhance the generation of a partial-thickness human skin equivalent in the mouse model, increasing hSCS engraftment (Lamin) and proliferation (Ki67), while reducing cellular senescence (p21) and DNA damage (53BP1).

Charge-Complementary Polymersomes for Enhanced mRNA Delivery

Messenger RNA (mRNA) therapies have emerged as potent and personalized alternatives to conventional DNA-based therapies. However, their therapeutic potential is frequently constrained by their molecular instability, susceptibility to degradation, and inefficient cellular delivery. This study presents the nanoparticle "ChargeSome" as a novel solution. ChargeSomes are designed to protect mRNAs from degradation by ribonucleases (RNases) and enable cell uptake, allowing mRNAs to reach the cytoplasm for protein expression via endosome escape. We evaluated the physicochemical properties of ChargeSomes using 1H nuclear magnetic resonance, Fourier-transform infrared, and dynamic light scattering. ChargeSomes formulated with a 9:1 ratio of mPEG-b-PLL to mPEG-b-PLL-SA demonstrated superior cell uptake and mRNA delivery efficiency. These ChargeSomes demonstrated minimal cytotoxicity in various in vitro structures, suggesting their potential safety for therapeutic applications. Inherent pH sensitivity enables precise mRNA release in acidic environments and structurally protects the encapsulated mRNA from external threats. Their design led to endosome rupture and efficient mRNA release into the cytoplasm by the proton sponge effect in acidic endosome environments. In conclusion, ChargeSomes have the potential to serve as effective secure mRNA delivery systems. Their combination of stability, protection, and delivery efficiency makes them promising tools for the advancement of mRNA-based therapeutics and vaccines.

Combinatorial design of ionizable lipid nanoparticles for muscle-selective mRNA delivery with minimized off-target effects

Ionizable lipid nanoparticles (LNPs) pivotal to the success of COVID-19 mRNA (messenger RNA) vaccines hold substantial promise for expanding the landscape of mRNA-based therapies. Nevertheless, the risk of mRNA delivery to off-target tissues highlights the necessity for LNPs with enhanced tissue selectivity. The intricate nature of biological systems and inadequate knowledge of lipid structure-activity relationships emphasize the significance of high-throughput methods to produce chemically diverse lipid libraries for mRNA delivery screening. Here, we introduce a streamlined approach for the rapid design and synthesis of combinatorial libraries of biodegradable ionizable lipids. This led to the identification of iso-A11B5C1, an ionizable lipid uniquely apt for muscle-specific mRNA delivery. It manifested high transfection efficiencies in muscle tissues, while significantly diminishing off-targeting in organs like the liver and spleen. Moreover, iso-A11B5C1 also exhibited reduced mRNA transfection potency in lymph nodes and antigen-presenting cells, prompting investigation into the influence of direct immune cell transfection via LNPs on mRNA vaccine effectiveness. In comparison with SM-102, while iso-A11B5C1's limited immune transfection attenuated its ability to elicit humoral immunity, it remained highly effective in triggering cellular immune responses after intramuscular administration, which is further corroborated by its strong therapeutic performance as cancer vaccine in a melanoma model. Collectively, our study not only enriches the high-throughput toolkit for generating tissue-specific ionizable lipids but also encourages a reassessment of prevailing paradigms in mRNA vaccine design. This study encourages rethinking of mRNA vaccine design principles, suggesting that achieving high immune cell transfection might not be the sole criterion for developing effective mRNA vaccines.

Inhalable Gene Therapy and the Lung Surfactant Problem

Lung-targeting RNA-carrying lipid nanoparticles (LNPs) are often intravenously administered and accumulate in the pulmonary endothelium. However, most respiratory diseases are localized in the airway or the alveolar epithelium. Inhalation has been explored as a more direct delivery method, but it presents its own challenges. We believe that one reason LNPs have failed to transfect RNA into alveolar epithelial cells is their interaction with the lung surfactant (LS). We propose that inhalable LNP design should take inspiration from biological agents and other nanoparticles to overcome this barrier. Screening should first focus on LS penetration and then be optimized for cell uptake and endosomal release. This will enable more efficient applications of RNA-LNPs in lung diseases.

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.

mRNA Cancer Vaccines: Construction and Boosting Strategies

In late 2020, the U.S. Food and Drug Administration (FDA) approved a lipid-based mRNA vaccine for the prevention of COVID-19, which has pushed this field to be more closely studied and motivated researchers to delve deeper into mRNA therapeutics. To date, the research on mRNA cancer vaccines has been developed rapidly, and substantial hopeful therapeutic results have been achieved against various solid tumors in clinical trials. In this review, we first introduce three main components of mRNA cancer vaccines, including mRNA antigens, adjuvants, and delivery vectors. Engineering these components can optimize the therapeutic effects of mRNA cancer vaccines. For instance, appropriate modification of mRNA structure can alleviate the poor stability and innate immunogenicity of mRNA, and the use of mRNA delivery vectors can address the issues of low delivery efficiency in vivo. Second, we emphatically discuss some strategies to further improve the efficacy of mRNA cancer vaccines, namely modulating the immunosuppressive tumor environment, optimizing administration routes, achieving targeting delivery to intended tissues or organs, and employing combination therapy. These strategies can strengthen the tumor inhibitory ability of mRNA cancer vaccines and increase the possibility of tumor elimination. Finally, we point out some challenges in the clinical practice of mRNA cancer vaccines and offer our perspectives on future developments in this rapidly evolving field. It is anticipated that mRNA cancer vaccines will be rapidly developed for clinical cancer therapy in the near future.

Engineering nanoparticle toolkits for mRNA delivery

The concept of using mRNA to produce its own medicine in situ in the body makes it an ideal drug candidate, holding great potential to revolutionize the way we approach medicine. The unique characteristics of mRNA, as well as its customizable biomedical functions, call for the rational design of delivery systems to protect and transport mRNA molecules. In this review, a nanoparticle toolkit is presented for the development of mRNA-based therapeutics from a drug delivery perspective. Nano-delivery systems derived from either natural systems or chemical synthesis, in the nature of organic or inorganic materials, are summarised. Delivery strategies in controlling the tissue targeting and mRNA release, as well as the role of nanoparticles in building and boosting the activity of mRNA drugs, have also been introduced. In the end, our insights into the clinical and translational development of mRNA nano-drugs are presented.

Research progress in mRNA drug modification and delivery systems

Messenger RNA (mRNA) has shown tremendous potential in disease prevention and therapy. The clinical application requires mRNA with enhanced stability and high translation efficiency, ensuring it not to be degraded by nucleases and targeting to specific tissues and cells. mRNA immunogenicity can be reduced by nucleotide modification, and translation efficiency can be enhanced by codon optimization. The 5´ capping structure and 3´ poly A increase mRNA stability, and the addition of 5' and 3' non-translational regions regulate mRNA translation initiation and protein production. Nanoparticle delivery system protects mRNA from degradation by ubiquitous nucleases, enhances mRNA concentration in circulation and assists it cytoplasmic entrance for the purpose of treatment and prevention. Here, we review the recent advances of mRNA technology, discuss the methods and principles to enhance mRNA stability and translation efficiency; summarize the requirements involved in designing mRNA delivery systems with the potential for industrial translation and biomedical application. Furthermore, we provide insights into future directions of mRNA therapeutics to meet the needs for personalized precision medicine.

The mRNA Vaccine Revolution: COVID-19 Has Launched the Future of Vaccinology

During the COVID-19 pandemic, mRNA (mRNA) vaccines emerged as leading vaccine candidates in a record time. Nonreplicating mRNA (NRM) and self-amplifying mRNA (SAM) technologies have been developed into high-performing and clinically viable vaccines against a range of infectious agents, notably SARS-CoV-2. mRNA vaccines demonstrate efficient in vivo delivery, long-lasting stability, and nonexistent risk of infection. The stability and translational efficiency of in vitro transcription (IVT)-mRNA can be further increased by modulating its structural elements. In this review, we present a comprehensive overview of the recent advances, key applications, and future challenges in the field of mRNA-based vaccinology.

Nanoadjuvants: Promising Bioinspired and Biomimetic Approaches in Vaccine Innovation

Adjuvants are the important part of vaccine manufacturing as they elicit the vaccination effect and enhance the durability of the immune response through controlled release. In light of this, nanoadjuvants have shown unique broad spectrum advantages. As nanoparticles (NPs) based vaccines are fast-acting and better in terms of safety and usability parameters as compared to traditional vaccines, they have attracted the attention of researchers. A vaccine nanocarrier is another interesting and promising area for the development of next-generation vaccines for prophylaxis. This review looks at the various nanoadjuvants and their structure-function relationships. It compiles the state-of-art literature on numerous nanoadjuvants to help domain researchers orient their understanding and extend their endeavors in vaccines research and development.

mRNA-based cancer therapeutics

Due to the fact that mRNA technology allows the production of diverse vaccines and treatments in a shorter time frame and with reduced expense compared to conventional approaches, there has been a surge in the use of mRNA-based therapeutics in recent years. With the aim of encoding tumour antigens for cancer vaccines, cytokines for immunotherapy, tumour suppressors to inhibit tumour development, chimeric antigen receptors for engineered T cell therapy or genome-editing proteins for gene therapy, many of these therapeutics have shown promising efficacy in preclinical studies, and some have even entered clinical trials. Given the evidence supporting the effectiveness and safety of clinically approved mRNA vaccines, coupled with growing interest in mRNA-based therapeutics, mRNA technology is poised to become one of the major pillars in cancer drug development. In this Review, we present in vitro transcribed mRNA-based therapeutics for cancer treatment, including the characteristics of the various types of synthetic mRNA, the packaging systems for efficient mRNA delivery, preclinical and clinical studies, current challenges and future prospects in the field. We anticipate the translation of promising mRNA-based treatments into clinical applications, to ultimately benefit patients.

Spleen-Targeted mRNA Delivery by Amphiphilic Carbon Dots for Tumor Immunotherapy

In recent years, the application of mRNA vaccine-based tumor immunotherapy invigorated anti-tumor therapy. However, the low efficiency of mRNA delivery and the lack of targeting ability in vivo are the major obstacles to achieving highly efficient immunotherapy. In this work, we report a chemical library of amphiphilic carbon dots (ACDs) and the synthesized ACDs were applied to mRNA delivery, bio-imaging, and tumor immunotherapy. The ACDs can smoothly bind with mRNA to form ACDs@mRNA nanocomplexes, and the fluorescent properties of the ACDs afforded the nanoparticles with bio-imaging ability. By screening of the ACDs, O₁₂-Tta-CDs were found to have optimal mRNA transfection efficiency and the ability of spleen-targeted delivery. In addition, O₁₂-Tta-CDs can well transfect the immune cells and promote the maturation and antigen presentation of bone marrow-derived dendritic cells (BMDCs). Furthermore, O₁₂-Tta-CDs@OVA-mRNA was successfully applied to inhibit tumor growth, and more specific T-cell infiltration was observed in spleen and tumors of mice after treatment in the E.G7-OVA tumor model. Besides, O₁₂-Tta-CDs@OVA-mRNA also achieved a good therapeutic effect in tumor recurrence inhibition and tumor prophylactic experiments. This study provided a new direction for the design of mRNA vectors, which is promising in tumor immunotherapy.

Development and applications of mRNA treatment based on lipid nanoparticles

Nucleic acid-based therapies such as messenger RNA have the potential to revolutionize modern medicine and enhance the performance of existing pharmaceuticals. The key challenges of mRNA-based therapies are delivering the mRNA safely and effectively to the target tissues and cells and controlling its release from the delivery vehicle. Lipid nanoparticles (LNPs) have been widely studied as drug carriers and are considered to be state-of-the-art technology for nucleic acid delivery. In this review, we begin by presenting the advantages and mechanisms of action of mRNA therapeutics. Then we discuss the design of LNP platforms based on ionizable lipids and the applications of mRNA-LNP vaccines for prevention of infectious diseases and for treatment of cancer and various genetic diseases. Finally, we describe the challenges and future prospects of mRNA-LNP therapeutics.

Emerging Trends in Lipid-Based Vaccine Delivery: A Special Focus on Developmental Strategies, Fabrication Methods, and Applications

Lipid-based vaccine delivery systems such as the conventional liposomes, virosomes, bilosomes, vesosomes, pH-fusogenic liposomes, transferosomes, immuno-liposomes, ethosomes, and lipid nanoparticles have gained a remarkable interest in vaccine delivery due to their ability to render antigens in vesicular structures, that in turn prevents its enzymatic degradation in vivo. The particulate form of lipid-based nanocarriers confers immunostimulatory potential, making them ideal antigen carriers. Facilitation in the uptake of antigen-loaded nanocarriers, by the antigen-presenting cells and its subsequent presentation through the major histocompatibility complex molecules, leads to the activation of a cascade of immune responses. Further, such nanocarriers can be tailored to achieve the desired characteristics such as charge, size, size distribution, entrapment, and site-specificity through modifications in the composition of lipids and the selection of the appropriate method of preparation. This ultimately adds to its versatility as an effective vaccine delivery carrier. The current review focuses on the various lipid-based carriers that have been investigated to date as potential vaccine delivery systems, the factors that affect their efficacy, and their various methods of preparation. The emerging trends in lipid-based mRNA vaccines and lipid-based DNA vaccines have also been summarized.

Research Advances on the Stability of mRNA Vaccines

Compared to other vaccines, the inherent properties of messenger RNA (mRNA) vaccines and their interaction with lipid nanoparticles make them considerably unstable throughout their life cycles, impacting their effectiveness and global accessibility. It is imperative to improve mRNA vaccine stability and investigate the factors influencing stability. Since mRNA structure, excipients, lipid nanoparticle (LNP) delivery systems, and manufacturing processes are the primary factors affecting mRNA vaccine stability, optimizing mRNA structure and screening excipients can effectively improve mRNA vaccine stability. Moreover, improving manufacturing processes could also prepare thermally stable mRNA vaccines with safety and efficacy. Here, we review the regulatory guidance associated with mRNA vaccine stability, summarize key factors affecting mRNA vaccine stability, and propose a possible research path to improve mRNA vaccine stability.

Delivery challenges for CRISPR-Cas9 genome editing for Duchenne muscular dystrophy

Duchene muscular dystrophy (DMD) is an X-linked neuromuscular disorder that affects about one in every 5000 live male births. DMD is caused by mutations in the gene that codes for dystrophin, which is required for muscle membrane stabilization. The loss of functional dystrophin causes muscle degradation that leads to weakness, loss of ambulation, cardiac and respiratory complications, and eventually, premature death. Therapies to treat DMD have advanced in the past decade, with treatments in clinical trials and four exon-skipping drugs receiving conditional Food and Drug Administration approval. However, to date, no treatment has provided long-term correction. Gene editing has emerged as a promising approach to treating DMD. There is a wide range of tools, including meganucleases, zinc finger nucleases, transcription activator-like effector nucleases, and, most notably, RNA-guided enzymes from the bacterial adaptive immune system clustered regularly interspaced short palindromic repeats (CRISPR). Although challenges in using CRISPR for gene therapy in humans still abound, including safety and efficiency of delivery, the future for CRISPR gene editing for DMD is promising. This review will summarize the progress in CRISPR gene editing for DMD including key summaries of current approaches, delivery methodologies, and the challenges that gene editing still faces as well as prospective solutions.

Development of Novel siRNA Therapeutics: A Review with a Focus on Inclisiran for the Treatment of Hypercholesterolemia

Over the past two decades, it was discovered that introducing synthetic small interfering RNAs (siRNAs) into the cytoplasm facilitates effective gene-targeted silencing. This compromises gene expression and regulation by repressing transcription or stimulating sequence-specific RNA degradation. Substantial investments in developing RNA therapeutics for disease prevention and treatment have been made. We discuss the application to proprotein convertase subtilisin/kexin type 9 (PCSK9), which binds to and degrades the low-density lipoprotein cholesterol (LDL-C) receptor, interrupting the process of LDL-C uptake into hepatocytes. PCSK9 loss-of-function modifications show significant clinical importance by causing dominant hypocholesterolemia and lessening the risk of cardiovascular disease (CVD). Monoclonal antibodies and small interfering RNA (siRNA) drugs targeting PCSK9 are a significant new option for managing lipid disorders and improving CVD outcomes. In general, monoclonal antibodies are restricted to binding with cell surface receptors or circulating proteins. Similarly, overcoming the intracellular and extracellular defenses that prevent exogenous RNA from entering cells must be achieved for the clinical application of siRNAs. N-acetylgalactosamine (GalNAc) conjugates are a simple solution to the siRNA delivery problem that is especially suitable for treating a broad spectrum of diseases involving liver-expressed genes. Inclisiran is a GalNAc-conjugated siRNA molecule that inhibits the translation of PCSK9. The administration is only required every 3 to 6 months, which is a significant improvement over monoclonal antibodies for PCSK9. This review provides an overview of siRNA therapeutics with a focus on detailed profiles of inclisiran, mainly its delivery strategies. We discuss the mechanisms of action, its status in clinical trials, and its prospects.

High-Precision Synthesis of RNA-Loaded Lipid Nanoparticles for Biomedical Applications

The recent development of RNA-based therapeutics in delivering nucleic acids for gene editing and regulating protein translation has led to the effective treatment of various diseases including cancer, inflammatory and genetic disorder, as well as infectious diseases. Among these, lipid nanoparticles (LNP) have emerged as a promising platform for RNA delivery and have shed light by resolving the inherent instability issues of naked RNA and thereby enhancing the therapeutic potency. These LNP consisting of ionizable lipid, helper lipid, cholesterol, and poly(ethylene glycol)-anchored lipid can stably enclose RNA and help them release into the cells' cytosol. Herein, the significant progress made in LNP research starting from the LNP constituents, formulation, and their diverse applications is summarized first. Moreover, the microfluidic methodologies which allow precise assembly of these newly developed constituents to achieve LNP with controllable composition and size, high encapsulation efficiency as well as scalable production are highlighted. Furthermore, a short discussion on current challenges as well as an outlook will be given on emerging approaches to resolving these issues.

Nucleic acid drug vectors for diagnosis and treatment of brain diseases

Nucleic acid drugs have the advantages of rich target selection, simple in design, good and enduring effect. They have been demonstrated to have irreplaceable superiority in brain disease treatment, while vectors are a decisive factor in therapeutic efficacy. Strict physiological barriers, such as degradation and clearance in circulation, blood-brain barrier, cellular uptake, endosome/lysosome barriers, release, obstruct the delivery of nucleic acid drugs to the brain by the vectors. Nucleic acid drugs against a single target are inefficient in treating brain diseases of complex pathogenesis. Differences between individual patients lead to severe uncertainties in brain disease treatment with nucleic acid drugs. In this Review, we briefly summarize the classification of nucleic acid drugs. Next, we discuss physiological barriers during drug delivery and universal coping strategies and introduce the application methods of these universal strategies to nucleic acid drug vectors. Subsequently, we explore nucleic acid drug-based multidrug regimens for the combination treatment of brain diseases and the construction of the corresponding vectors. In the following, we address the feasibility of patient stratification and personalized therapy through diagnostic information from medical imaging and the manner of introducing contrast agents into vectors. Finally, we take a perspective on the future feasibility and remaining challenges of vector-based integrated diagnosis and gene therapy for brain diseases.

A tale of nucleic acid-ionizable lipid nanoparticles: Design and manufacturing technology and advancement

INTRODUCTION

Ionizable lipid nanoparticles (LNPs) have been proven to have high encapsulation, cellular uptake, and effective endosomal escape and are therefore promising for nucleic acid delivery. The combination of ionizable lipids, helper lipids, cholesterol, and PEG lipids advances nucleic acid-ionizable LNPs and distinguishes them from liposomes, SLNs, NLCs, and other lipid particles. Solvent injection and microfluidics technology are the primary manufacturing techniques for commercialized ionizable LNPs. Microfluidics technology limitations restrict the rapid industrial scale-up and therapeutic effectiveness of ionized LNPs. Alternative manufacturing technologies and target-specific lipids are urgently needed.

AREA COVERED

This article provides an in-depth update on the lipid compositions, clinical trials, and manufacturing technologies for nucleic acid-ionizable LNPs. For the first time, we updated the distinction between ionizable LNPs and other lipid particles. We also proposed an alternate thermocycling technology for high industrial scale-up and the stability of nucleic acid-ionizing LNPs.

EXPERT OPINION

Nucleic acid-ionizable LNPs have a promising future for delivering nucleic acids in a target-specific manner. Though ionizing LNPs are in their early stages, they face several challenges, including only hepatic delivery, a short shelf life, and ultra-cold storage. In our opinion, ligand-based, target-specific synthesized novel lipids and advanced manufacturing technologies can easily overcome the restrictions and open up a new approach for improved therapeutic efficacy for chronic disorders.