Nanomaterial-enabled RNA therapeutics: bridging delivery barriers to clinical translation

Introduction

RNA-based therapeutics have emerged as a distinct and versatile class of biomedical interventions with applications spanning infectious diseases, cancer, and inherited genetic disorders. Unlike conventional small-molecule drugs, which typically act by modulating protein function, RNA therapeutics operate at the level of gene expression, enabling sequence-specific regulation of disease-associated pathways (Rohner et al., 2022; Sahin et al., 2014). This capability allows RNA molecules to either suppress pathogenic gene expression or promote the production of therapeutic proteins, offering flexibility across diverse clinical contexts. Advances in RNA synthesis, chemical modification, and molecular biology have further supported the development of multiple RNA modalities, including messenger RNA (mRNA), small interfering RNA (siRNA), microRNA (miRNA), and CRISPR-associated guide RNAs, each with distinct mechanisms of action and therapeutic potential (Kanasty et al., 2013; Dowdy, 2017).

Despite these advances, the clinical translation of RNA therapeutics remains fundamentally constrained by delivery-related challenges. RNA molecules exhibit limited stability under physiological conditions and are highly susceptible to rapid degradation by nucleases present in biological fluids (Tang and Khvorova, 2024). In addition, their large molecular size, polyanionic character, and hydrophilic nature significantly limit passive diffusion across cellular membranes, resulting in inefficient cytosolic delivery (Yin et al., 2014a). Following systemic administration, RNA therapeutics may also trigger innate immune responses, undergo rapid clearance by the reticuloendothelial system, and display non-specific biodistribution, collectively reducing therapeutic efficacy and increasing the risk of off-target effects (Kowalski et al., 2019). These factors have established delivery as the primary bottleneck in the clinical development of RNA-based medicines.

Nanomaterial-based delivery systems have therefore become central to efforts aimed at overcoming these biological and physicochemical barriers. By encapsulating or electrostatically complexing RNA molecules, nanocarriers can enhance RNA stability, improve circulation time, and facilitate cellular uptake through endocytic pathways (Peer et al., 2020). A wide range of nanomaterial platforms, including lipid-based nanoparticles, polymeric carriers, inorganic nanomaterials, and hybrid or biomimetic systems, have been investigated for RNA delivery, each offering distinct advantages and limitations with respect to loading efficiency, targeting capability, intracellular trafficking, and safety (Hou et al., 2021; Mitchell et al., 2020). Importantly, the biological performance of these systems is strongly governed by physicochemical parameters such as particle size, surface charge, composition, and surface chemistry, which critically influence circulation stability, immune recognition, biodistribution, and endosomal escape (Blanco et al., 2015).

Although substantial progress has been made in the development of RNA therapeutics and nanomaterial-based delivery systems, several important conceptual and translational gaps remain insufficiently addressed in current literature. Existing reviews frequently focus either on specific RNA modalities, individual nanocarrier classes, or isolated delivery barriers without systematically integrating how nanocarrier physicochemical properties influence biological interactions, intracellular trafficking, therapeutic performance, and clinical feasibility. In particular, limited emphasis has been placed on understanding why certain delivery platforms, especially lipid nanoparticles, have achieved successful clinical translation whereas many polymeric, inorganic, and biomimetic systems remain confined to preclinical investigation despite promising experimental outcomes. Furthermore, translational factors such as manufacturability, scalability, reproducibility, safety optimisation, and regulatory considerations are often discussed independently rather than as interconnected determinants of clinical success. Therefore, this review aims to bridge these gaps by providing an integrated design-to-clinic perspective that links material engineering principles with biological barriers, delivery efficiency, and translational performance to guide the rational development of next-generation RNA nanotherapeutics.

Although many nanomaterial-based RNA delivery systems have demonstrated promising preclinical efficacy, successful clinical translation remains limited. Challenges related to large-scale manufacturing, batch-to-batch reproducibility, long-term safety, and regulatory approval continue to restrict the progression of numerous delivery platforms beyond early-stage development (Fang et al., 2022). These limitations underscore the need for a more integrated understanding of how nanocarrier design parameters intersect with biological barriers and translational constraints. In this context, the present review critically examines recent advances in nanomaterial-enabled RNA delivery systems while comparatively evaluating the biological and translational factors governing their clinical applicability. By integrating insights from nanotechnology, RNA biology, and translational medicine, this review aims to provide a coherent framework for the rational development of clinically viable RNA nanotherapeutics.

To provide a structured translational perspective, this review first summarises the major classes of RNA therapeutics and their distinct delivery requirements. Subsequently, the principal nanomaterial platforms for RNA delivery, including lipid-based, polymeric, inorganic, and hybrid biomimetic systems, are comparatively discussed with respect to their physicochemical characteristics and biological performance. The review then examines the major biological barriers limiting clinical translation and analyses current engineering strategies developed to overcome these challenges, including surface functionalization, targeting ligands, stimuli-responsive systems, and endosomal escape enhancement approaches. Finally, clinically approved and late-stage RNA nanotherapeutics are critically evaluated alongside translational limitations, manufacturing challenges, safety considerations, and emerging future directions, including artificial intelligence-guided nanocarrier engineering and personalised nanomedicine.

RNA therapeutics: molecular classes and delivery requirements

mRNA therapeutics

Messenger RNA (mRNA) therapeutics enable transient intracellular protein expression without integrating into the host genome, thereby avoiding the risk of insertional mutagenesis associated with DNA-based therapies (Sahin et al., 2020). Their versatility has driven applications in infectious disease vaccines, cancer immunotherapy, and protein replacement therapies. However, the therapeutic translation of mRNA remains strongly dependent on efficient delivery because mRNA molecules are intrinsically unstable, highly susceptible to nuclease degradation, and inefficiently internalised due to their large size and polyanionic nature.

In addition to poor cellular uptake, exogenous mRNA can activate innate immune receptors such as TLR7/8 and RIG-I, resulting in inflammatory responses that reduce translational efficiency (Karikó et al., 2005). Consequently, nanocarrier systems including lipid nanoparticles (LNPs), polymeric carriers, and hybrid biomimetic systems have become essential for protecting mRNA cargo and facilitating intracellular transport. Among these, ionizable lipid-based systems are particularly effective because they remain relatively neutral during circulation but become protonated within acidic endosomes, promoting membrane destabilisation and cytosolic release. Structural optimisation of mRNA through modified nucleosides such as pseudouridine further improves translation efficiency while reducing immune activation (Morais and Yu, 2025). The clinical success of COVID-19 mRNA vaccines demonstrated the feasibility of large-scale mRNA delivery and established LNP-mediated delivery as a benchmark platform for RNA therapeutics (Polack et al., 2020; Baden et al., 2021; Carthew and Sontheimer, 2009).

siRNA and miRNA therapeutics

Small interfering RNAs (siRNAs) and microRNAs (miRNAs) function through RNA interference (RNAi)-mediated suppression of gene expression (Bernstein et al., 2001; Tyagi et al., 2025; Lee et al., 2003). Although both operate through the RNA-induced silencing complex (RISC), siRNAs typically exhibit near-perfect complementarity to target mRNAs, resulting in sequence-specific transcript cleavage, whereas miRNAs commonly regulate multiple genes through partial complementarity, leading to broader but less specific post-transcriptional regulation (Li et al., 2025; Serra et al., 2025; Sanchis-Pascual et al., 2025).

The therapeutic potential of siRNAs has been validated clinically, particularly for diseases involving previously “undruggable” targets, with approved examples including patisiran and givosiran (Davidson and McCray, 2011; Setten et al., 2019; Adams et al., 2025; Scott, 2020). In contrast, miRNA-based therapies remain more challenging because their broad regulatory activity increases the risk of off-target modulation and systemic dysregulation (Yu et al., 2022). Despite their relatively small size, both siRNA and miRNA therapeutics face major delivery limitations including rapid nuclease degradation, renal clearance, poor tissue penetration, and immune recognition (Yu et al., 2022; Contractor et al., 2026; Lennox and Behlke, 2016; Birmingham et al., 2006; Nikan et al., 2025). Accordingly, diverse nanocarrier systems such as cationic lipids, polymers, dendrimers, and cell-penetrating peptides have been developed to improve RNA stability, cellular uptake, and cytosolic delivery. Chemical modifications including 2′-O-methyl substitutions further reduce immune activation and off-target effects while improving therapeutic stability (Kanasty et al., 2013, Yin et al., 2014a).

CRISPR/cas RNA systems

CRISPR/Cas systems have revolutionised gene editing by enabling programmable and sequence-specific genomic modification (Fa et al., 2025; Mehnath, 2026; Finn et al., 2018). RNA-based CRISPR delivery strategies commonly involve co-delivery of Cas9 mRNA and single-guide RNA (sgRNA), allowing transient nuclease expression while reducing the risk of permanent genomic integration associated with DNA-based systems (Kumar et al., 2025). Following delivery, the sgRNA directs Cas proteins to complementary genomic targets, where site-specific DNA cleavage enables gene disruption or correction through endogenous repair pathways (Chen et al., 2025; Naruka et al., 2025).

Compared with mRNA and siRNA therapeutics, CRISPR/Cas systems present substantially greater delivery complexity because they require synchronised delivery of multiple large biomolecular components, efficient intracellular trafficking, and, in many cases, nuclear localisation (Yin et al., 2014b). In addition, prolonged nuclease activity and off-target genome editing remain major safety concerns (Kalter et al., 2025). Lipid nanoparticles, polymeric carriers, and hybrid nanocarriers have therefore been explored to improve cargo protection, coordinated release, and intracellular delivery efficiency. Among these, LNP-mediated delivery has shown promising editing efficiency in hepatocytes and hematopoietic cells in preclinical studies (Kleinstiver et al., 2016). Ongoing efforts focus on improving sgRNA specificity, minimising immune recognition, and optimising tissue-targeted delivery to enhance the precision and translational safety of CRISPR-based therapeutics (Charlesworth et al., 2019).

The major RNA therapeutic modalities differ considerably in their molecular complexity, intracellular trafficking requirements, duration of action, and translational delivery challenges, which consequently influence nanocarrier design strategies and clinical applicability (Table 1; Figure 1). mRNA therapeutics generally require efficient cytosolic delivery of relatively large and immunogenic RNA cargos to support transient protein expression, whereas siRNA/miRNA systems involve smaller duplex RNAs primarily designed for post-transcriptional gene silencing. In contrast, CRISPR/Cas systems present substantially greater delivery complexity due to the requirement for co-delivery of multiple editing components and efficient nuclear localisation. These differences highlight why delivery systems optimised for one RNA modality frequently demonstrate limited performance when directly adapted to another, emphasising the need for modality-specific nanocarrier engineering approaches.

TABLE 1. Comparative overview of major RNA therapeutic modalities and their delivery requirements.

Nanomaterial platforms for RNA deliver

Lipid nanoparticles

Lipid nanoparticles (LNPs) are currently the most clinically advanced non-viral platforms for RNA delivery, largely due to the success of siRNA therapeutics and mRNA vaccines (Zong et al., 2023). Typical LNP formulations consist of four key components: ionizable lipids, helper phospholipids, cholesterol, and PEG-lipid conjugates (Brimacombe et al., 2025). Ionizable lipids remain relatively neutral under physiological conditions to minimise systemic toxicity but become protonated within acidic endosomes, promoting membrane destabilisation and cytosolic RNA release (Liao et al., 2026). Helper lipids and cholesterol contribute to membrane stability and fusion, whereas PEG-lipids enhance colloidal stability and prolong circulation by reducing opsonisation and clearance by the mononuclear phagocyte system.

The clinical success of LNPs has validated their ability to protect RNA cargo, facilitate cellular uptake, and support efficient intracellular delivery, as demonstrated by approved siRNA therapies and highly effective COVID-19 mRNA vaccines (Polack et al., 2020; Adams et al., 2018). However, despite these advances, endosomal escape remains a major intracellular bottleneck, with only a limited fraction of internalised RNA successfully reaching the cytosol (Sabnis et al., 2018). In addition, LNPs frequently exhibit preferential hepatic accumulation mediated by ApoE adsorption and LDL receptor uptake, which may contribute to off-target liver exposure and dose-associated hepatotoxicity (Liu et al., 2026).

Immunogenicity and formulation-associated safety also remain important challenges. Although PEGylation improves nanoparticle stability and circulation time, excessive PEG density may impair cellular uptake and endosomal escape while repeated administration can induce anti-PEG antibodies, accelerated blood clearance, and hypersensitivity reactions. Consequently, alternative stealth strategies, including cleavable PEG linkers, polysarcosine, and poly (2-oxazoline)-based coatings, are being explored to improve immune compatibility without compromising delivery efficiency (Nogueira et al., 2020). Furthermore, large-scale manufacturing requires strict control of formulation parameters to ensure reproducibility and GMP compliance, while cold-chain storage requirements continue to limit global distribution and accessibility (Roces et al., 2020).

Polymeric nanocarriers

Polymeric materials have been extensively explored for RNA delivery and have been shown to prevent premature RNA degradation and facilitate cytosolic delivery to target cells (Ulko et al., 2019). They are divided into two main categories based on the physiological charges they carry. The categories include cationic polymers, which are the most commonly used due to their ability to form complexes with anionic RNA molecules via electrostatic interactions, and non-cationic polymers, which exhibit lower in vitro and in vivo toxicity (Whitehead et al., 2009). There is a special class of polymers derived from stimuli-responsive behaviour; it includes endogenous (pH, enzymes, redox environment, etc.) and exogenous (electromagnetic radiation, etc.) (Mura et al., 2013). The use of stimuli-responsive polymers has improved the specificity and efficiency of RNA delivery (Kaczmarek et al., 2017).

Cationic polymers

Cationic polymers are among the most extensively investigated polymeric nanocarriers for RNA delivery because their positively charged amine groups enable efficient electrostatic complexation with negatively charged RNA molecules, forming protective polyplexes that enhance cellular uptake and reduce nuclease degradation (Mura et al., 2013). In addition to RNA condensation, these protonable amine groups facilitate endosomal escape through proton sponge-mediated osmotic swelling and membrane destabilisation.

Among these systems, poly (ethyleneimine) (PEI) remains a benchmark carrier due to its high transfection efficiency, although its clinical applicability is restricted by significant cytotoxicity and non-specific interactions. Dendrimeric systems such as poly (amidoamine) (PAMAM) provide structurally defined and tunable architectures, whereas biodegradable polymers including poly (β-amino ester)s (PBAEs) offer improved biocompatibility through hydrolysable backbones that reduce long-term toxicity while maintaining efficient delivery. Other classes, including cationic polyacrylates, polypeptides, and glycopolymers, further contribute functionalities such as pH-responsive release, membrane translocation, and receptor-mediated interactions. Despite their strong intracellular delivery efficiency, the clinical translation of cationic polymers remains limited by the inherent trade-off between efficacy and safety. High cationic charge density improves RNA binding and endosomal escape but frequently induces membrane destabilisation, haemolysis, immune activation, and non-specific serum interactions, resulting in rapid clearance and off-target effects (Kaczmarek et al., 2017). Consequently, current strategies increasingly focus on biodegradable, charge-shielded, and hybrid polymer systems designed to balance transfection efficiency with improved biocompatibility and in vivo stability (Table 2).

TABLE 2. Representative cationic polymers for RNA delivery: structural features, mechanisms, advantages, and limitations.

Non-cationic polymers

Non-cationic polymers have emerged as important alternatives to cationic delivery systems due to their improved biocompatibility, reduced cytotoxicity, and favourable in vivo stability. Unlike cationic polymers that rely primarily on electrostatic RNA complexation, non-cationic systems generally utilise steric encapsulation, hydrophobic interactions, or matrix-based entrapment to protect RNA cargo from enzymatic degradation. These materials are frequently incorporated as structural matrices or shielding components within hybrid nanocarriers to prolong circulation time and minimise non-specific biological interactions.

Poly (ethylene glycol) (PEG) is widely used as a steric stabiliser that forms a hydration shell around nanoparticles, thereby reducing protein adsorption and immune recognition. Similarly, biodegradable polyesters such as PLA, PLGA, and PCL function as controlled-release matrices that gradually release RNA through hydrolytic degradation. Hybrid polyester systems further improve functionality by integrating cationic or lipid-based components to enhance RNA loading while maintaining favourable safety profiles (Kamaly et al., 2016). By considering these advantages, non-cationic polymers often demonstrate lower intrinsic transfection efficiency than cationic systems because of their limited ability to directly complex and internalise RNA. In addition, excessive steric shielding, particularly through PEGylation, may reduce cellular uptake and endosomal escape, illustrating the trade-off between systemic stability and intracellular delivery efficiency. Consequently, current strategies increasingly focus on multifunctional hybrid systems combining non-cationic polymers with ionizable lipids, targeting ligands, or stimuli-responsive elements to improve translational performance while preserving biocompatibility (Table 3).

TABLE 3. Non-cationic polymer platforms for RNA delivery: structural features, mechanisms, and applications.

Stimuli responsive polymers

Stimuli-responsive polymers represent an advanced class of smart nanocarriers designed to achieve controlled and site-specific RNA delivery in response to internal or external triggers. Unlike conventional polymeric systems that primarily rely on passive degradation or diffusion, these materials undergo physicochemical changes in response to environmental cues, thereby enabling triggered RNA release and improved intracellular delivery (Kamaly et al., 2016). Endogenous stimuli such as acidic pH, redox gradients, and enzymatic activity exploit pathological microenvironments to destabilise nanocarriers and promote cargo release, whereas exogenous triggers including light, ultrasound, magnetic fields, and temperature provide externally controlled activation with enhanced spatial and temporal precision.

Mechanistically, these systems commonly operate through polymer cleavage, charge reversal, or phase transitions that facilitate carrier destabilisation and endosomal escape. For example, pH-responsive polymers become protonated within acidic endosomes, while redox-sensitive linkers undergo intracellular cleavage to release RNA payloads. Similarly, photo-responsive and thermo-responsive systems enable externally regulated delivery with improved targeting control. Although stimuli-responsive polymers offer significant advantages for improving targeting specificity and controlled RNA release, several translational challenges remain, including limited trigger reliability, restricted tissue penetration of external stimuli, scalability issues, and variability in physiological responsiveness across biological environments (Emadi et al., 2026). Therefore, current research increasingly focuses on multi-stimuli-responsive and hybrid biomimetic systems to enhance delivery robustness, reproducibility, and clinical applicability (Table 4)

TABLE 4. Mechanistic overview of externally triggered stimuli-responsive polymer systems for RNA delivery: mechanisms, materials, and applications.

Inorganic nanomaterials

Inorganic nanomaterials have attracted significant interest for RNA delivery because of their tunable morphology, high surface area, imaging capability, and stimulus-responsive properties (Vasti et al., 2025). These systems are frequently combined with lipids or polymers to form hybrid nanocarriers that improve RNA loading, protection, and intracellular delivery.

Among these materials, gold nanoparticles (AuNPs) are particularly well studied due to their biocompatibility, facile synthesis, and surface plasmon resonance properties that support photothermal therapy and optical imaging applications (Patil et al., 2025). RNA molecules can be efficiently conjugated to AuNPs through thiol-gold interactions, forming spherical nucleic acids (SNAs) with enhanced stability, cellular uptake, and prolonged therapeutic activity. Notably, SNAs have demonstrated the ability to penetrate the blood–brain and blood–tumour barriers, enabling silencing of oncogenic targets such as Bcl2L12 in glioma models (Jensen et al., 2013).

Other inorganic systems including carbon nanomaterials and mesoporous silica nanoparticles (MSNs) have also shown promise for RNA delivery. Functionalised carbon nanotubes, graphene-based systems, and nanodiamonds facilitate intracellular transport of small RNAs, whereas MSNs provide large surface areas and tunable pore structures suitable for RNA loading and combination therapies (Alidori et al., 2016; Meng et al., 2010). In addition, dissolvable inorganic systems such as calcium phosphate nanoparticles, iron oxide nanoparticles, and metal–organic frameworks (MOFs) are increasingly explored because of their improved biodegradability and reduced risk of long-term tissue accumulation (Table 5) (Paris et al., 2019). Although inorganic nanomaterials offer unique theranostic and stimulus-responsive functionalities, their clinical translation remains limited by concerns regarding biodegradability, long-term biosafety, complex surface engineering, and regulatory challenges. Consequently, current approaches increasingly focus on hybrid inorganic-organic systems designed to combine imaging capability and controlled release with improved biocompatibility and translational potential.

TABLE 5. Representation of inorganic nanocarriers for RNA delivery: loading strategies, release mechanisms, and biomedical applications.

Inorganic nanomaterials provide unique imaging and stimulus-responsive functionalities; however, their clinical translation remains restricted by challenges related to endosomal escape, long-term accumulation, immune recognition, and manufacturing complexity (Fadeel and Garcia-Bennett, 2010). Non-biodegradable or slowly degrading particles may accumulate in off-target tissues, while protein corona formation can alter biodistribution and promote clearance by the mononuclear phagocyte system (Avasthi et al., 2025). Strategies such as renal-clearable nanoparticle design and surface modification with PEG or zwitterionic ligands have therefore been explored to improve circulation behaviour and reduce immune recognition (Prins et al., 2026). Nevertheless, achieving an optimal balance among stability, functionality, biodegradability, and scalable manufacturing remains difficult, particularly for complex hybrid structures requiring GMP-compliant production and standardised characterisation methods.

Hybrid and biomimetic nanomaterials have consequently emerged to address the limitations of conventional nanocarriers by combining synthetic tunability with biological compatibility (Yoo et al., 2011). Lipid–polymer hybrid nanoparticles (LPHNPs), for example, integrate the structural stability of polymeric cores with the biocompatibility and membrane fusion properties of lipid shells, thereby improving RNA encapsulation, circulation stability, and intracellular delivery (Mukherjee et al., 2019). Optimised hybrid systems have demonstrated enhanced mRNA transfection, improved endosomal escape, and reduced cytotoxicity compared with conventional lipid nanoparticles (Miao et al., 2019). Biomimetic systems including exosome-mimetic vesicles and cell membrane-coated nanoparticles further improve immune evasion, targeting specificity, and intracellular trafficking (Kamerkar et al., 2017; Fang et al., 2018). These systems exploit native membrane proteins and “self” markers such as CD47 to reduce protein corona formation and prolong systemic circulation (Lyu et al., 2025; Luk et al., 2012; Rodriguez et al., 2013). In addition, advanced surface engineering approaches including ligand functionalization, click chemistry, and genetic modification enable improved receptor-mediated uptake and tissue-specific targeting (Yoo et al., 2011; Hou et al., 2026).

Despite their promising biological performance, hybrid and biomimetic systems continue to face translational challenges associated with manufacturing complexity, batch variability, scalability limitations, and the absence of standardised regulatory frameworks, particularly for exosome-based platforms (Hua et al., 2018). Comprehensive in vivo evaluation of biodistribution, clearance, immunogenicity, and long-term safety therefore remain essential for their successful clinical development. Figure 2 illustrates the intracellular delivery pathways and stimuli-responsive release mechanisms of representative RNA nanocarriers, including pH-, redox-, and ROS-triggered systems.

Major RNA delivery platforms differ substantially in their biological interactions, translational performance, and clinical feasibility (Table 6). Lipid nanoparticles (LNPs) currently represent the most clinically advanced RNA delivery systems due to their efficient endosomal escape, scalable manufacturing, and favourable regulatory translation. Polymeric nanocarriers offer greater structural tunability and stimuli responsiveness but remain constrained by cytotoxicity, batch variability, and inconsistent in vivo performance. Inorganic nanomaterials provide unique imaging, theragnostic, and stimulus-responsive functionalities; however, concerns regarding long-term accumulation, biodegradability, and regulatory complexity continue to limit their clinical progression. Hybrid and biomimetic systems attempt to integrate the advantages of multiple platforms, particularly improved immune evasion and targeting specificity, yet manufacturing complexity and reproducibility remain significant translational barriers. Overall, these comparisons demonstrate that successful clinical translation depends not only on delivery efficiency but also on achieving an optimal balance among biocompatibility, scalability, reproducibility, and safety.

TABLE 6. Comparative framework of major nanomaterial platforms for RNA delivery.

The superior clinical translation of lipid nanoparticles (LNPs) compared with many alternative nanocarrier systems can be attributed to their ability to achieve a favourable balance among delivery efficiency, biocompatibility, manufacturability, and regulatory feasibility. Ionizable lipids enable efficient RNA encapsulation and pH-responsive endosomal escape while maintaining relatively low systemic toxicity under physiological conditions. In addition, LNPs can be produced reproducibly at large scale using well-established microfluidic manufacturing approaches compatible with GMP requirements. Their physicochemical properties, including particle size, surface composition, and encapsulation efficiency, are also comparatively easier to standardise and optimise for regulatory approval. In contrast, many polymeric systems remain limited by cytotoxicity, non-specific interactions, and batch-to-batch variability, whereas inorganic nanomaterials frequently face concerns related to biodegradability, long-term accumulation, and regulatory complexity. Similarly, hybrid and biomimetic systems, despite improved targeting and immune evasion capabilities, continue to encounter major challenges associated with manufacturing scalability, purification, reproducibility, and quality control. Collectively, these factors suggest that successful clinical translation depends not solely on delivery performance but on the integration of efficacy, safety, scalability, and regulatory compatibility within a clinically manufacturable platform.

Biological barriers limiting clinical translation

Biological barriers remain a major limitation in the clinical translation of RNA therapeutics and largely account for the discrepancy between promising in vitro performance and limited in vivo efficacy. Following systemic administration, RNA nanocarriers undergo substantial delivery losses, with approximately 90% cleared during circulation, nearly 98% trapped within endosomal compartments, and a large proportion subsequently degraded in lysosomes, resulting in less than 1% productive cytosolic delivery (Wilhelm et al., 2016). Although many nanocarrier systems demonstrate high transfection efficiency under controlled in vitro conditions, systemic factors including nuclease degradation, opsonisation, protein corona formation, and clearance by the mononuclear phagocyte system significantly reduce delivery efficiency in vivo (Blanco et al., 2015).

Importantly, these quantitative estimates are derived from representative preclinical in vivo studies involving systemically administered nanocarriers and may vary substantially depending on RNA modality, nanocarrier composition, administration route, dosage, animal model, and target tissue (Hosseini-Kharat et al., 2025). For example, liver-targeted lipid nanoparticles generally demonstrate higher intracellular delivery efficiencies than tumour-targeted or extrahepatic systems because of ApoE-mediated hepatic uptake and the comparatively permissive vascular architecture of the liver. Similarly, endosomal escape efficiencies differ considerably across nanocarrier classes and cell types, highlighting the challenges associated with directly extrapolating delivery performance across experimental models (Pei, 2025).

Systemic stability and immune recognition

Systemic stability is a prerequisite for effective RNA delivery. Naked RNA is rapidly degraded by serum nucleases, while nanocarriers face opsonisation and sequestration in clearance organs such as the liver (65%) and spleen (15%) (Wilhelm et al., 2016); naked RNA exhibits t₁/₂ = 2.5 min (serum), 0.3 min (plasma) due to RNase I/Dcp2 cleavage (Wadhwa et al., 2020). The formation of a protein corona alters particle identity, often reducing circulation time and promoting off-target accumulation. PEGylation, zwitterionic coatings, and biomimetic membranes have been used to alter immune recognition. Still, these modifications can simultaneously hinder cellular uptake and endosomal escape, highlighting the trade-off between stability and functionality (Suk et al., 2016). Among the multiple biological barriers limiting RNA nanotherapeutic translation, endosomal escape is widely regarded as the principal intracellular bottleneck. Although many nanocarriers achieve efficient cellular internalisation, only a limited fraction of internalised RNA successfully escapes endosomal compartments before lysosomal degradation, thereby substantially restricting productive cytosolic delivery (Gilleron et al., 2013). Consequently, insufficient endosomal escape frequently limits therapeutic efficacy even when systemic stability and cellular uptake are optimised.

Cellular uptake and endosomal escape

Efficient cytosolic delivery requires both cellular internalisation and endosomal escape, yet <2% of internalised nanoparticles reach the cytosol despite 95% uptake (Sabnis et al., 2018; Gilleron et al., 2013). While cationic polymers and ionizable lipids facilitate uptake and promote endosomal disruption, these mechanisms are often inefficient or cytotoxic in vivo. The proton sponge effect, fusogenic peptides, and membrane-destabilising agents have been explored to enhance escape, yet reproducibility across diverse cell types and tissues remains limited (Chahal et al., 2026). Importantly, quantitative studies indicate that productive endosomal escape remains one of the least efficient steps in intracellular RNA delivery. Although up to 95% of nanoparticles may undergo cellular internalisation, typically less than 1%–2% successfully escape endosomal compartments to achieve functional cytosolic delivery. A substantial fraction is instead recycled back to the extracellular environment or trafficked toward lysosomal degradation pathways. Furthermore, the precise molecular mechanisms governing endosomal escape in vivo remain incompletely understood and appear highly dependent on nanocarrier composition, intracellular trafficking dynamics, endosomal maturation state, and cell type (Jozić et al., 2026). These findings highlight endosomal escape as a major translational bottleneck despite extensive optimisation of uptake efficiency. Consequently, many systems that perform well in vitro fail to achieve sufficient cytosolic release in vivo.

Tissue targeting and biodistribution

Tissue targeting faces 80% clearance organ accumulation: liver (65% ± 8%), spleen (15% ± 4%), lungs (8%), leaving 0.8% ± 0.3% tumour delivery 24 h post-IV (1 mg/kg) (Wilhelm et al., 2016). Nanocarriers frequently accumulate in clearance organs, limiting delivery to intended sites. Passive targeting via the enhanced permeability and retention effect is inconsistent across tumour types, while active targeting strategies using ligands or antibodies face challenges of heterogeneity and receptor saturation. Biological barriers such as the extracellular matrix and endothelial tight junctions further restrict penetration into solid tissues. Stimuli-responsive designs and biomimetic coatings have shown promise, but consistent and predictable biodistribution remains evasive (Rosenblum et al., 2018).

The sharp decline in efficacy from in vitro to in vivo settings illustrates why many promising RNA nanocarrier systems fail to translate clinically. Overcoming these barriers will require integrated strategies that balance systemic stability, immune evasion, efficient cellular trafficking, and precise tissue targeting, supported by predictive in vivo models that more faithfully recapitulate human physiology (Blanco et al., 2015). Major biological barriers encountered during systemic RNA delivery are closely linked to specific nanocarrier engineering strategies designed to improve translational performance (Table 7).

TABLE 7. Relationship between major biological barriers and nanocarrier engineering strategies.

Design strategies to bridge delivery gaps

Successful clinical translation of RNA nanocarriers requires integrated engineering strategies that simultaneously address systemic instability, immune recognition, inefficient intracellular trafficking, endosomal entrapment, and limited tissue specificity (Kulkarni et al., 2018; Haghighi et al., 2024). Rather than functioning as isolated material modifications, modern nanocarrier design approaches increasingly combine surface engineering, stimuli responsiveness, and intracellular release mechanisms to optimise both biological performance and translational feasibility (Mitchell et al., 2020; Blanco et al., 2015). In this context, three interconnected strategies, surface functionalization and targeting, stimuli-responsive delivery, and enhancement of endosomal escape, have emerged as central design principles for improving RNA delivery efficiency and clinical applicability (Kaczmarek et al., 2017).

A major challenge in RNA nanocarrier engineering lies in balancing the interconnected trade-offs among systemic stability, cellular uptake, endosomal escape, biocompatibility, and translational scalability. For instance, surface shielding strategies such as PEGylation improve circulation stability and reduce immune clearance but may simultaneously hinder cellular internalisation and endosomal escape. Similarly, highly cationic materials enhance RNA condensation and intracellular delivery efficiency yet frequently increase cytotoxicity and non-specific biological interactions. Stimuli-responsive and biomimetic systems attempt to address these competing requirements by enabling selective activation, controlled intracellular release, and improved targeting specificity while preserving systemic compatibility. Consequently, successful RNA nanotherapeutic design increasingly depends on integrated optimisation of multiple physicochemical and biological parameters rather than maximisation of any single delivery property (Liu et al., 2024). The interconnected trade-offs among delivery efficiency, systemic stability, biocompatibility, and translational feasibility that govern RNA nanocarrier design are comparatively summarised in Table 8.

TABLE 8. Major design trade-offs in RNA nanocarrier engineering.

Surface functionalisation and targeting ligands

Surface engineering plays a critical role in regulating circulation stability, biodistribution, immune recognition, and cellular uptake (Suk et al., 2016). Among available approaches, PEGylation remains the most widely used strategy for reducing protein corona formation and prolonging systemic circulation through steric shielding (Knop et al., 2010). However, excessive PEG density may simultaneously reduce cellular uptake and endosomal escape, illustrating the translational trade-off between systemic stability and intracellular delivery efficiency (Hatakeyama et al., 2011). Cleavable PEG linkers and low-density PEG formulations have therefore been developed to preserve circulation stability while enabling recovery of intracellular delivery activity (Mahalingam et al., 2024).

Active targeting ligands further improve tissue specificity through receptor-mediated uptake mechanisms. Antibodies, peptides, aptamers, and small molecules have been conjugated to nanocarrier surfaces to selectively target disease-associated receptors. Notably, GalNAc conjugation has demonstrated high hepatocyte specificity and has become central to several clinically approved siRNA therapies (Springer and Dowdy, 2018). Similarly, biomimetic surface engineering strategies employing erythrocyte, platelet, or cancer-cell membranes enhance immune evasion and prolong circulation while simultaneously improving tissue targeting through native membrane-associated proteins (Fang et al., 2018; Rodriguez et al., 2013). Collectively, these strategies demonstrate how surface engineering directly influences the balance among immune compatibility, biodistribution, and delivery efficiency.

Stimuli-responsive and smart nanocarriers

Stimuli-responsive nanocarriers enhance delivery precision by enabling controlled RNA release in response to pathological or externally applied triggers (Mura et al., 2013). Endogenous stimuli including acidic pH, redox gradients, and enzymatic activity exploit disease-associated microenvironments to destabilise nanocarriers and promote intracellular cargo release, whereas external stimuli such as light, ultrasound, and temperature provide spatial and temporal control over delivery (Sutradhar et al., 2025). These systems improve tissue specificity and reduce off-target exposure by coupling material responsiveness with local biological conditions.

Advanced smart nanocarriers increasingly integrate multiple responsive elements to achieve more precise control over intracellular release kinetics and therapeutic activity. In addition, theranostic platforms combining RNA delivery with imaging functionalities enable real-time monitoring of biodistribution and therapeutic response (Cheng et al., 2013; Ryu et al., 2014). Such multifunctional systems highlight the growing shift from passive delivery platforms toward adaptive nanocarriers capable of simultaneously improving targeting, release efficiency, and therapeutic monitoring.

Endosomal escape enhancement strategies

Endosomal escape remains one of the principal intracellular bottlenecks limiting productive RNA delivery (Chahal et al., 2026). Although many nanocarriers achieve efficient cellular uptake, only a small fraction of internalised RNA successfully escapes endosomal compartments before lysosomal degradation. Consequently, considerable effort has focused on engineering nanocarriers capable of destabilising endosomal membranes while maintaining acceptable biocompatibility.

Cationic polymers such as PEI facilitate endosomal escape through proton sponge-mediated osmotic swelling, although their clinical applicability remains limited by cytotoxicity (Boussif et al., 1995). Ionizable lipids provide a more clinically successful alternative by becoming protonated within acidic endosomes and promoting membrane destabilisation, a mechanism central to the success of LNP-based mRNA vaccines and siRNA therapeutics (Liao et al., 2026). Additional approaches including fusogenic peptides, membrane-active agents, and photochemical internalisation further enhance cytosolic release by promoting membrane fusion or disruption (Lönn et al., 2016). Biomimetic strategies employing exosome-derived membranes or viral-mimetic mechanisms have also shown promise for improving intracellular trafficking and escape efficiency (Kamerkar et al., 2017).

Collectively, these strategies demonstrate that specific nanocarrier engineering approaches are increasingly designed to address distinct biological delivery barriers. Surface shielding and biomimetic coatings primarily improve systemic stability and reduce immune clearance, whereas targeting ligands enhance tissue specificity and cellular uptake. Similarly, stimuli-responsive systems enable controlled intracellular release within pathological microenvironments, while ionizable lipids, proton sponge polymers, and fusogenic agents are specifically engineered to overcome endosomal entrapment and improve productive cytosolic delivery. Such integrated barrier-oriented design strategies are essential for improving the translational performance of RNA nanotherapeutics. Among current delivery strategies, ionizable lipid nanoparticle (LNP) systems and GalNAc-mediated targeting approaches remain the most clinically validated owing to their reproducible manufacturing, efficient intracellular delivery, and favourable regulatory translation. In contrast, advanced experimental systems including photoresponsive, magnetic, and ultrasound-triggered nanocarriers demonstrate promising spatiotemporal control and targeting precision in preclinical models but remain limited by challenges related to scalability, tissue penetration, device dependency, and clinical standardization (Cao et al., 2025; Qin et al., 2025). These comparisons highlight that translational success depends not only on delivery functionality but also on manufacturability, reproducibility, and clinical feasibility.

Figure 3 summarises the principal mechanisms underlying endosomal escape, including proton sponge-mediated osmotic rupture, pH-triggered membrane fusion, and membrane destabilisation pathways.

Clinical translation of RNA nanotherapeutics

The clinical translation of RNA nanotherapeutics highlights the ongoing gap between promising preclinical results and clinical feasibility. Although many nanocarrier systems exhibit strong efficacy in vitro and in animal models, few have progressed to regulatory approval or late-stage clinical trials. This gap is primarily due to challenges in scaling up complex nanomaterials, achieving reproducibility, and satisfying rigorous safety and regulatory standards. Analyses of approved and late-stage therapies elucidate the design principles that facilitate successful clinical translation (Hua et al., 2018).

Gap addressed: preclinical success vs. clinical feasibility

Clinically approved and late-stage systems

A major milestone in RNA nanotherapeutics is the approval of lipid nanoparticle (LNP)-based delivery systems. Onpattro (patisiran), the first FDA-approved siRNA therapy, demonstrated that ionizable lipid formulations can efficiently enable hepatic delivery, induce robust gene silencing, and maintain acceptable safety profiles (Adams et al., 2025). This efficacy resulted from careful optimisation of lipid composition, PEGylation to enhance systemic stability, and GalNAc conjugation to target hepatocytes. Likewise, mRNA vaccines for COVID-19, delivered via LNPs, highlighted the scalability and clinical applicability of RNA nanocarriers (Polack et al., 2020). These vaccines achieved global deployment due to their capacity to encapsulate large RNA payloads, promote endosomal escape, and induce transient protein expression with manageable safety profiles.

Late-stage clinical platforms now include GalNAc-conjugated siRNAs, which employ receptor-mediated uptake in hepatocytes (Ryu et al., 2014). Their success is attributed to straightforward design, reproducible synthesis, and predictable biodistribution. In contrast, polymeric and inorganic systems, despite significant preclinical investigation, have not reached similar clinical milestones. This disparity highlights that clinical success is determined not only by efficacy but also by manufacturability, scalability, and regulatory compliance (Cullis and Felgner, 2024).

The superior clinical translation of lipid nanoparticle (LNP)-based systems is largely attributable to their ability to balance delivery efficiency, biocompatibility, scalable manufacturing, and regulatory feasibility. Ionizable lipid formulations enable efficient RNA encapsulation and pH-responsive endosomal escape while maintaining comparatively acceptable in vivo safety profiles. Furthermore, LNPs possess relatively well-defined physicochemical properties and are compatible with reproducible microfluidic manufacturing technologies that support GMP-compliant large-scale production and quality control. In contrast, many polymeric and inorganic nanocarriers continue to face translational limitations associated with cytotoxicity, structural heterogeneity, complex surface engineering, poor biodegradability, long-term tissue accumulation, and batch-to-batch variability. Several clinically investigated systems, including the cyclodextrin polymer-based CALAA-01 platform and the siRNA therapeutic revusiran, demonstrated promising early-stage gene silencing but were discontinued because of toxicity, immune-related adverse events, or insufficient therapeutic benefit despite encouraging preclinical outcomes (Davis et al., 2010; Fitzgerald et al., 2017).

Despite the remarkable clinical success of liver-targeted RNA therapeutics, efficient extrahepatic delivery remains one of the most significant unresolved challenges in RNA nanomedicine. Most clinically approved systems, including LNP-based therapeutics and GalNAc-conjugated siRNAs, preferentially accumulate in the liver owing to ApoE-mediated uptake, fenestrated hepatic vasculature, and favourable biodistribution profiles. In contrast, delivery to extrahepatic tissues such as the lungs, CNS, solid tumours, and immune cells remains substantially less efficient due to complex biological barriers. Pulmonary delivery is restricted by mucus penetration and alveolar clearance, CNS targeting is limited by the blood–brain barrier, and tumour-targeted delivery is hindered by heterogeneous vascular permeability, dense extracellular matrices, and elevated interstitial pressure. Similarly, efficient RNA delivery to immune cells remains challenging because of poor nanoparticle internalization and rapid intracellular degradation. Consequently, the development of safe, selective, and clinically scalable extrahepatic delivery platforms remains a major priority for next-generation RNA nanotherapeutics and is essential for expanding the therapeutic applicability of RNA medicines beyond hepatic diseases (Dalabehera et al., 2025). Collectively, these observations emphasise that successful clinical translation depends not solely on delivery performance but also on safety, reproducibility, manufacturability, and regulatory compatibility.

Manufacturing, scale-up, and reproducibility

Manufacturing and scale-up present significant obstacles to clinical translation. Nanocarriers typically require complex multi-component formulations, precise control over particle size and charge, and consistent encapsulation of RNA cargo. Although laboratory methods can produce small batches with high efficiency, scaling up to industrial production often introduces variability that may compromise safety and efficacy. Lipid nanoparticles (LNPs) have benefited from established microfluidic mixing technologies, which facilitate reproducible large-scale production under Good Manufacturing Practice (GMP) conditions (Cullis and Hope, 2017). In contrast, polymeric and hybrid systems frequently involve intricate synthesis procedures or biological components, such as exosomes, that are challenging to standardise, leading to batch-to-batch variability (Whitford and Guterstam, 2019). Reproducibility is further challenged by the sensitivity of nanocarrier performance to subtle formulation changes. Small variations in lipid ratios, polymer chain length, or surface ligand density can substantially affect biodistribution and immune recognition. Regulatory agencies require rigorous characterisation and quality control; however, standardised methods for complex nanomaterials are still limited (Ehmann et al., 2013). Addressing these challenges necessitates advances in scalable manufacturing technologies, robust analytical tools, and harmonised regulatory guidelines.

Safety, toxicity, and regulatory considerations

Safety and toxicity are primary concerns in the development of RNA nanotherapeutics. Although cationic polymers demonstrate efficacy in vitro, they frequently induce cytotoxicity, haemolysis, and immune activation in vivo (Volovat et al., 2026). Inorganic nanomaterials present risks of long-term accumulation and organ toxicity, especially in the liver and spleen. LNPs, while clinically successful, may still cause infusion reactions, complement activation, or transient increases in liver enzyme levels (Szegedi et al., 2026). Consequently, regulatory agencies mandate comprehensive toxicological assessments, including studies on biodistribution, clearance, immunogenicity, and long-term safety (Table 9).

TABLE 9. From design to clinic: discussion of approved RNA nanotherapeutics and their key delivery features.

Design strategies often conflict with regulatory requirements. For instance, increasing cationic charge density can improve transfection efficiency but also heightens toxicity, whereas PEGylation extends circulation time but may decrease cellular uptake. Hybrid and biomimetic delivery systems add further complexity, as their multi-component structures complicate characterisation and raise concerns regarding reproducibility and immunogenicity (Amaeze et al., 2025; Yousefi Adlsadabad et al., 2024). Regulatory frameworks are evolving to address these advanced platforms; however, the absence of standardised assays and predictive models delays approval processes. Successful clinical translation requires not only innovative design but also adherence to safety, scalability, and regulatory standards.

Translational gaps and future perspectives

While RNA nanotherapeutics have experienced swift development from hypothesis to clinical implementation, they still have notable translational gaps. These gaps indicate a divergence between advanced laboratory formulations and scalable manufacturing, an ongoing compromise between delivery efficiency and safety, and the drawbacks of existing regulatory frameworks. To overcome these challenges, recent developments such as AI-guided design, personalised nanomedicine, and combination strategies have shown promising potential for resolving them.

Collectively, these translational gaps indicate that successful clinical implementation of RNA nanotherapeutics depends on coordinated optimisation across four interconnected dimensions: delivery efficiency, safety and biocompatibility, manufacturing reproducibility, and regulatory scalability. Improvements in one parameter frequently compromise another, creating translational trade-offs that cannot be resolved through isolated material modifications alone. Consequently, next-generation RNA nanocarrier development increasingly requires integrated design frameworks that combine rational material engineering, predictive computational modelling, scalable manufacturing, and precision biological targeting to achieve clinically viable translation.

Design–manufacturing disconnect

A major translational limitation in RNA nanomedicine lies in the disconnect between highly optimised laboratory-scale formulations and reproducible large-scale manufacturing. Many advanced nanocarrier systems rely on complex multi-component architectures, precise surface engineering, and biologically derived materials such as exosomes, all of which remain difficult to standardise under GMP-compliant manufacturing conditions (Kaczmarek et al., 2017). Even minor variations in lipid composition, polymer chain length, or ligand density can substantially alter biodistribution, immune recognition, and therapeutic performance, thereby complicating reproducibility and regulatory translation.

Among current delivery platforms, LNPs have achieved the greatest clinical success largely because they are compatible with scalable and reproducible microfluidic manufacturing technologies (Hou et al., 2021). In contrast, polymeric, hybrid, and exosome-based systems frequently exhibit batch-to-batch variability and lack standardised purification and characterisation protocols, limiting their translational consistency (Luisotti et al., 2025). Recent studies further suggest that manufacturing variability may reduce reproducibility by 30%–40% between preclinical and scaled production systems (Crommelin et al., 2020). Consequently, future translational progress will require integrated advances in scalable synthesis, process automation, standardised analytical frameworks, and predictive formulation optimisation. In this context, AI-assisted modelling approaches are increasingly being explored to improve formulation reproducibility and reduce dependence on empirical trial-and-error design strategies (Bannigan et al., 2021).

Safety vs. delivery efficiency trade-offs

A central challenge in RNA nanotherapeutic translation is balancing delivery efficiency with long-term safety and biocompatibility. Strategies that improve intracellular delivery frequently introduce safety-related limitations. For example, increased cationic charge density enhances RNA condensation, cellular uptake, and endosomal escape but also promotes cytotoxicity, haemolysis, and immune activation (Kotwal et al., 2025). Similarly, PEGylation improves circulation stability and reduces immune clearance, yet excessive surface shielding may impair cellular internalisation and intracellular trafficking (Sutradhar et al., 2025). Inorganic nanomaterials further illustrate this trade-off, as their structural stability and imaging capabilities are often accompanied by concerns regarding long-term accumulation in clearance organs such as the liver and spleen (Yin et al., 2014a).

Clinically approved RNA therapeutics demonstrate how successful translation depends on achieving a controlled balance between efficacy and tolerability. Patisiran (Onpattro) achieved approximately 80% transthyretin (TTR) reduction with manageable infusion-related reactions (Adams et al., 2025), whereas Inclisiran demonstrated sustained LDL-cholesterol reduction with relatively low toxicity through targeted GalNAc-mediated delivery (Ray et al., 2020). Likewise, mRNA COVID-19 vaccines achieved high clinical efficacy while maintaining generally acceptable transient systemic side effects (Polack et al., 2020). Collectively, these examples highlight that translational success depends not on maximising delivery efficiency alone but on integrated optimisation of efficacy, safety, and manufacturability. Consequently, future nanocarrier design strategies must increasingly prioritise biocompatibility, controlled biodistribution, and predictive safety profiling alongside delivery performance.

Emerging tools to bridge gaps

Emerging technologies are increasingly reshaping RNA nanomedicine by enabling more predictive, adaptive, and personalised delivery strategies. AI and machine learning approaches are being explored to predict nanocarrier behaviour, optimise RNA sequences, and improve formulation safety and efficacy by integrating large datasets related to material properties, biodistribution, and immune responses (Bannigan et al., 2021). Recent studies employing deep learning-based whole-body nanocarrier imaging have further demonstrated the potential of AI-assisted prediction of tissue targeting and clearance at single-cell resolution (Alafeef et al., 2020). In addition, computational optimisation of lipid and polymer compositions is reducing reliance on empirical trial-and-error formulation strategies.

Despite these advances, several limitations continue to restrict the clinical implementation of AI-guided nanocarrier design. Machine learning models remain highly dependent on the availability of large, standardised, and biologically representative datasets, which are often limited in nanomedicine research. Furthermore, variability across experimental models, inconsistencies in nanoparticle characterisation, and limited interpretability of predictive algorithms may reduce the reliability and generalisability of AI-derived predictions in clinical settings. In addition, regulatory frameworks for AI-assisted nanomedicine development remain poorly standardised, and prospectively validated clinical prediction models capable of reliably translating preclinical findings into human therapeutic outcomes are still lacking. Consequently, successful integration of AI into RNA nanomedicine will require standardized datasets, transparent computational frameworks, rigorous experimental validation, and harmonised regulatory evaluation strategies to ensure reliable translational applicability (Han et al., 2025).

Parallel advances in genomics, transcriptomics, and biomimetic engineering are also driving the development of personalised RNA nanomedicine. Autologous exosomes, cell membrane-coated nanoparticles, and other biomimetic systems may reduce immune rejection while improving tissue-specific delivery (Luisotti et al., 2025; Pr et al., 2026). In addition, multifunctional co-delivery platforms capable of simultaneously transporting RNA therapeutics, chemotherapeutics, adjuvants, or imaging agents have demonstrated enhanced therapeutic synergy and theranostic potential in preclinical studies (Hou et al., 2021; Polack et al., 2020; Sun et al., 2025; Laxane and Yadav, 2025; Wang et al., 2025).

Collectively, these emerging strategies reflect a broader shift toward precision-integrated RNA nanomedicine, in which computational modelling, biomimetic engineering, multifunctional delivery systems, and personalized therapeutic design converge to address interconnected translational barriers simultaneously. Future clinical translation will likely depend on integrated nanocarrier platforms capable of achieving scalable manufacturing, adaptive biological responsiveness, targeted intracellular delivery, and predictive safety profiling within a single translational framework. In this context, the convergence of artificial intelligence, biomimetic materials engineering, and clinically scalable manufacturing technologies is expected to define the next generation of clinically viable RNA nanotherapeutics. Accordingly, Table 10 summarizes a proposed translational framework outlining the key design priorities required for the development of clinically viable next-generation RNA nanocarriers.

TABLE 10. Future design framework for clinically translatable RNA nanocarriers.

Conclusion

RNA-based therapeutics have emerged as highly versatile platforms for treating infectious diseases, cancer, and genetic disorders; however, their successful clinical translation remains fundamentally constrained by delivery-related biological and translational barriers. Rapid nuclease degradation, immune recognition, inefficient tissue penetration, and limited endosomal escape collectively restrict productive intracellular RNA delivery despite promising preclinical performance. Consequently, the development of clinically viable RNA nanotherapeutics increasingly depends on integrated nanocarrier engineering strategies capable of balancing delivery efficiency, safety, manufacturability, and regulatory feasibility. Several key design principles have emerged as critical for future RNA nanocarrier development. First, efficient endosomal escape remains essential for productive cytosolic delivery and therapeutic efficacy. Second, surface engineering strategies including PEGylation, targeting ligands, and biomimetic coatings must balance systemic stability with cellular uptake and immune compatibility. Third, multifunctional and stimuli-responsive systems capable of integrating targeting, controlled release, and intracellular responsiveness offer significant advantages for improving delivery precision while minimising off-target effects. Fourth, scalable manufacturing, reproducibility, biodegradability, and predictive safety profiling must be incorporated into nanocarrier design at early developmental stages to improve translational feasibility. The clinical success of lipid nanoparticle-based systems such as Patisiran and mRNA vaccines demonstrates the transformative potential of rationally engineered RNA delivery platforms. Looking forward, the convergence of artificial intelligence-guided formulation design, biomimetic engineering, precision-targeted delivery, and scalable manufacturing technologies is expected to drive the next-generation of clinically translatable RNA nanotherapeutics. By integrating material innovation with translational and regulatory considerations, future progress in RNA nanomedicine will ultimately depend on overcoming the challenge of safe, reproducible, and clinically scalable extrahepatic systems capable of achieving efficient tissue-specific cytosolic RNA delivery.

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Footnotes

Edited by: Aamir Suhail, Harvard Medical School, United States

Reviewed by: Elahe Haghighi, Shiraz University of Medical Sciences, Iran

Yihang Wu, Shenzhen Campus of Sun Yat-Sen University, China