Nanotechnology in dsRNA Delivery

 

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Nanotechnology has become one of the most important enabling tools for RNA interference (RNAi) because naked double-stranded RNA (dsRNA) is easily degraded, poorly internalized, and often trapped before it reaches the cytoplasm. Across plants, fungi, arthropods, and vertebrates, nanocarriers improve dsRNA or siRNA performance by condensing RNA, shielding it from nucleases and adverse pH, promoting uptake through cell walls or epithelia, extending persistence on biological surfaces, and in some cases facilitating endosomal escape and tissue targeting. The field is not biologically uniform: in plants and many arthropods, long dsRNA is practical and often preferred, whereas in vertebrates long dsRNA is usually immunostimulatory, so nanomedicine has largely converged on short interfering RNA (siRNA). The most mature agricultural applications are sprayable or orally delivered nanoformulations for crop protection and pest suppression; the most mature biomedical application is lipid nanoparticle (LNP)-enabled siRNA therapy, exemplified by patisiran. Taken together, current evidence shows that nanotechnology does not merely “carry” RNA, but determines whether gene silencing is transient or durable, local or systemic, and experimental or truly translational.

RNAi is a conserved eukaryotic gene-silencing mechanism in which dsRNA-derived small RNAs guide sequence-specific suppression of complementary transcripts. Its conceptual appeal is obvious: it is programmable, highly sequence-specific, and adaptable to crop protection, functional genomics, and therapy. Its practical bottleneck is delivery. RNA is large, polyanionic, hydrophilic, and sensitive to RNases; plant cells add a rigid wall, insects add alkaline guts and dsRNases, fungi differ widely in environmental RNA uptake, and mammals add serum instability, immune sensing, reticuloendothelial clearance, and endosomal sequestration. Nanotechnology addresses these barriers through material design rather than sequence design alone.

Nanocarrier Platforms
The leading platforms fall into five broad classes. Inorganic carriers such as layered double hydroxide (LDH) clays and silica protect RNA and enable slow release. Carbon-based systems, including carbon dots and carbon quantum dots, are attractive where size matters, especially in plants. Polymeric and biopolymeric carriers such as chitosan, star polycations, cyclodextrin polymers, and PLGA-based hybrids condense RNA electrostatically and often improve mucosal or gut delivery. Peptide-based nanocapsules can enhance oral uptake in arthropods. Lipid systems, especially ionizable LNPs, dominate vertebrate translation because they combine high encapsulation efficiency, hepatocyte delivery, and scalable manufacture. Biogenic vesicles such as exosomes are appealing when tissue specificity or barrier crossing is critical, especially in the nervous system.

Applications in Plants and Plant-Associated Systems
Plant systems illustrate how nanocarriers can convert RNAi from a lab method into a field-facing technology. The landmark “BioClay” study by Mitter et al. showed that dsRNA loaded onto LDH clay nanosheets remained detectable on sprayed leaves for up to 30 days and provided sustained antiviral protection, solving one of the central weaknesses of naked foliar dsRNA: rapid wash-off and degradation. That study established controlled release, surface persistence, and topical practicality as core design criteria for agricultural RNA nanotechnology.

Subsequent work expanded beyond viral protection to direct gene silencing in plant tissues. Zhang et al. demonstrated that DNA nanostructures can enter mature plant cells and deliver siRNA, and that uptake depends on size, stiffness, compactness, and attachment geometry. This was important mechanistically because it showed that plant nanodelivery is not only possible, but designable. Schwartz et al. then showed that carbon dots enable low-pressure spray delivery of siRNA into Nicotiana benthamiana and tomato, producing strong silencing of both transgenes and endogenous magnesium chelatase genes. More recently, Sun et al. engineered cationized bovine serum albumin (cBSA)/dsRNA nanocomplexes that produced systemic silencing in tobacco and poplar after local application through petioles or shoots, suggesting that plant RNA nanotechnology is moving from local foliar effects toward whole-shoot and meristem-level responses.

Plant-pathogen systems add another layer. McLoughlin et al. showed that exogenous dsRNA can suppress Sclerotinia sclerotiorum and Botrytis cinerea, and Qiao et al. later showed that environmental RNA uptake varies sharply across fungi and oomycetes. That heterogeneity matters: in pathosystems where uptake is already strong, nanotechnology mainly improves persistence and dose efficiency; where uptake is intrinsically weak, formulation alone may not rescue performance. Thus, the fungal frontier is promising but still more biologically contingent than antiviral plant delivery.

Applications in Insects and Other Arthropods
Arthropods are among the most active arenas for dsRNA nanodelivery because many target pests are susceptible to environmental RNAi, yet oral delivery is undermined by gut nucleases, extreme pH, and poor epithelial uptake. Das et al. compared chitosan, carbon quantum dot, and silica nanoparticle delivery of dsRNA in Aedes aegypti and showed that nanocarriers can materially improve larval gene silencing. Avila et al. then used branched amphiphilic peptide capsules (BAPCs) to deliver lethal dsRNAs through insect diets, enhancing mortality in both the aphid Acyrthosiphon pisum and the beetle Tribolium castaneum. This was a key proof that nanotechnology could make feeding-based RNAi substantially more potent.

Chitosan has emerged as one of the most practical arthropod carriers because it is cationic, biodegradable, and comparatively inexpensive. In Helicoverpa armigera, Kolge et al. reported chitosan nanoparticles with high dsRNA loading, protection against gut nucleases and alkaline hydrolysis, uptake into gut cells, and bioassay-level lethality tied to silencing of lipase and chitinase targets. In Apolygus lucorum, Qiao et al. showed that chitosan/dsRNA nanoparticles were stable on plant surfaces for 48 hours, reached midgut epithelial cells and hemolymph after feeding, reduced target-gene expression by about 70%, and increased mortality by about 50%. These studies are especially important because they push RNAi toward realistic crop-protection scenarios rather than injection-based assays.

Nanotechnology is also expanding RNAi into non-model and beneficial arthropods. Wang et al. used star polycation-mediated dsRNA soaking in the predatory mite Phytoseiulus persimilis, sharply reducing reproductive output and enabling functional studies in a biologically important natural enemy. Zhou et al. then provided mechanistic insight in the mite Tetranychus cinnabarinus, showing that chitosan/dsRNA polyplex nanoparticles enhance environmental RNAi in part by activating clathrin-dependent endocytosis. Together, these studies suggest that arthropod nanodelivery is no longer just empirical formulation work; it is becoming a mechanistically grounded field.

Applications in Vertebrates and Humans
In vertebrates, the delivery problem is solved differently because long dsRNA usually activates innate immune sensors such as TLR3, RIG-I, and MDA5. As a result, vertebrate “dsRNA delivery” has largely become siRNA nanodelivery. Even so, the same principles apply: protection, biodistribution control, cell entry, and endosomal escape. Davis et al. provided the first direct evidence of RNAi in humans from systemically administered, targeted nanoparticles in cancer patients, marking a historic transition from concept to clinical mechanism. Alvarez-Erviti et al. showed that engineered exosomes can deliver siRNA across the blood-brain barrier to mouse brain, knocking down BACE1 and demonstrating that endogenous nanovesicles can solve tissue-access problems that synthetic systems often struggle with.

The deepest translational success has come from LNPs. Dong et al. reported highly potent lipopeptide nanoparticles that silenced liver genes in rodents and nonhuman primates, and degradable LNPs later achieved more than 90% PCSK9 silencing with durable LDL lowering in cynomolgus monkeys. Jyotsana et al. extended the paradigm beyond liver-centric delivery by showing efficient LNP-siRNA uptake in bone marrow and reduced leukemic burden in a mouse chronic myeloid leukemia model. The clearest clinical proof of maturity is patisiran, an LNP-formulated siRNA therapeutic for hereditary transthyretin amyloidosis: the APOLLO program showed large transthyretin reductions and meaningful clinical benefit, and later work extended efficacy into transthyretin cardiomyopathy. Newer systems are also trying to move beyond hepatic delivery. For example, Alameh et al. showed that chitosan siRNA nanoparticles can accumulate in kidney cortex and achieve functional knockdown with lower toxicity than conventional cationic lipid systems, pointing toward organ-selective post-LNP designs.

Challenges and Future Directions
Three challenges cut across organisms. First, carrier design must match barrier biology. A formulation optimized for leaf-surface persistence may fail in an insect gut, and a liver-tropic LNP is not automatically useful for brain, kidney, or tumor delivery. Second, uptake is not enough; cytosolic release remains a major bottleneck, especially in vertebrates. Third, specificity at the sequence level does not eliminate systems-level risk. Off-target silencing, ecological exposure of non-target arthropods, emergence of RNAi resistance through altered uptake or dsRNase activity, and formulation persistence in the environment all require case-by-case evaluation.

The next wave of progress will likely come from biodegradable, stimuli-responsive carriers that release cargo in defined microenvironments; hybrid systems that combine targeting ligands with endosome-disruptive chemistry; and more explicit integration of comparative organismal biology into formulation design. In agriculture, that means matching nanocarriers to cuticle chemistry, phyllosphere conditions, and pest feeding mode. In medicine, it means moving beyond hepatocytes toward extrahepatic precision delivery without sacrificing safety or manufacturability.

Conclusion
Nanotechnology has changed RNAi from a powerful idea into a deployable platform. In plants, it has made topical and even systemic silencing practical. In arthropods, it has transformed fragile environmental RNAi into orally active, biologically meaningful gene knockdown. In vertebrates, it has enabled the first approved RNAi medicines. The unifying lesson is that gene silencing efficacy is not dictated by RNA sequence alone; it is co-determined by the carrier, the barrier landscape of the target organism, and the intracellular route taken after uptake. The most successful future applications will therefore come from treating RNA and nanomaterials as a single integrated therapeutic or biocontrol system.

References:

• Mitter et al., 2017, BioClay for sustained antiviral RNAi in plants: PubMed
• Zhang et al., 2019, DNA nanostructures for siRNA delivery in mature plants: PMC
• Schwartz et al., 2020, carbon dots for spray siRNA delivery in plants: PMC
• Sun et al., 2024, dsRNA-protein nanoparticles for systemic silencing in plants: PMC
• McLoughlin et al., 2018, exogenous dsRNA against Sclerotinia and Botrytis: PubMed
• Qiao et al., 2021, fungal/oomycete differences in environmental RNA uptake: PubMed
• Das et al., 2015, nanoparticle-mediated dsRNA delivery in Aedes aegypti: PubMed
• Avila et al., 2018, BAPC oral dsRNA delivery in aphids and beetles: PubMed
• Wang et al., 2022, star polycation-mediated dsRNA soaking in predatory mites: PubMed
• Kolge et al., 2023, chitosan nanocarriers for Helicoverpa armigera: ScienceDirect
• Qiao et al., 2023, oral chitosan/dsRNA delivery in Apolygus lucorum: PubMed
• Zhou et al., 2023, clathrin-dependent uptake of chitosan/dsRNA nanoparticles in mites: ScienceDirect
• Davis et al., 2010, first evidence of RNAi in humans via targeted nanoparticles: PubMed
• Alvarez-Erviti et al., 2011, exosome-mediated siRNA delivery to mouse brain: Nature Biotechnology
• Dong et al., 2014, potent lipopeptide nanoparticles in rodents and nonhuman primates: PubMed
• Biodegradable LNPs for durable PCSK9 silencing in monkeys, 2017: PubMed
• Jyotsana et al., 2019, LNP-siRNA therapy for leukemia in vivo: PubMed
• Adams et al., 2018, patisiran phase 3 in hereditary transthyretin amyloidosis: Repository record
• Maurer et al., 2023, patisiran in transthyretin cardiac amyloidosis: PubMed
• Alameh et al., 2024, chitosan siRNA nanoparticles for kidney gene silencing: PubMed