Smart nanocarriers for plant genetic engineering

Main text

Nanocarriers are revolutionizing plant genetic engineering by enabling the direct and efficient delivery of nucleic acids and proteins into plant cells. Through precise control and customization of their properties, nanocarriers can effectively penetrate the plant cell wall and deliver bioactive molecules, thereby bypassing the need for plant genotype-specific compatibility. This technology provides a powerful, flexible, and broadly applicable strategy to improve crop health and resilience.

Conventional plant transformation methods, such as Agrobacterium-mediated gene transfer and biolistic delivery, are often limited by species specificity, long regeneration times, and increased risks of genomic instability (Neelakandan and Wang, 2012). Nanomaterial-based delivery systems are more flexible, but they face the significant challenge of penetrating the complex, multilayered plant cell wall (Lowry et al., 2024). Recent research has identified three effective strategies to overcome this obstacle: optimizing particle size, modifying surface charge, and using cell-wall-degrading enzymes (Figure 1). These approaches greatly enhance nanocarrier uptake, enabling the delivery of diverse bioactive agents such as nucleic acids, proteins, and gene-editing tools, and making nanotechnology a promising strategy for crop improvement.

Figure 1.

Design principles of nanocarriers for plant genetic engineering.

(A) Surface charge–mediated electrostatic interaction. Carbon dots functionalized with low-molecular-weight polyethyleneimine exhibit a moderate to strong positive charge. These positively charged nanocarriers electrostatically adhere to the negatively charged pectic and hemicellulosic components of the plant cell wall. This concentrates the nanocarriers at the cell wall interface, facilitating their penetration into plant cells.

(B) Enzymatic surface functionalization. Layered double hydroxide (LDH) nanosheets coated with lysozyme enhance cell wall permeability. Lysozyme, an enzyme that degrades cell walls, it partially degrades structural polysaccharides in plant cell walls, thereby increasing their permeability. In addition, lysozyme-coated nanoparticles stimulate active endocytosis in plant cells, significantly improving the uptake and delivery efficiency of large genetic payloads, including plasmids up to 15 kb in size.

(C) Aspect ratio and size optimization. Rod-shaped or sheet-like nanocarriers, engineered with quaternary amine groups to maintain a permanent positive charge, efficiently traverse the plant cell wall when their smallest dimension remains below approximately 20 nm. Incorporation of enzymes such as cellulase further increases cell wall permeability, thereby facilitating the delivery of cargo such as nucleic acids and proteins. Further functionalization with organelle-targeting enzyme-powered autonomous nanomotors may enable precise delivery to specific subcellular compartments, such as chloroplasts and mitochondria.

Enzyme-coated nanocarriers

A recent study by Yong et al. (2025) introduced a bio-inspired delivery system that used layered double hydroxide (LDH) nanosheets coated with lysozyme to increase plant cell wall permeability. Lysozyme, an enzyme that degrades bacterial cell walls, was shown to facilitate nanocarrier entry by partially degrading structural polysaccharides in plant cell walls, thereby increasing permeability. Lysozyme-coated nanoparticles also induced plant cell endocytosis, significantly increasing the cellular uptake of genetic material. After crossing the cell wall, nanocarriers must also traverse the plasma membrane, which can occur via passive diffusion, membrane fusion, or active processes such as endocytosis; the last of these has been demonstrated for lysozyme-coated LDH (Yong et al., 2025). This platform was shown to efficiently deliver a wide range of genetic payloads, including synthetic mRNA, double-stranded RNA, small interfering RNA, and plasmid DNA up to 15 kb long, across species such as tobacco, tomato, and sorghum, and into tissues ranging from roots to developing pollen (Yong et al., 2025). Although delivery efficiency declined with increasing plasmid size, complicating the delivery of genome editors (which are typically large), recently developed hypercompact editors offer a potential solution (Weiss et al., 2025). Because LDH is biodegradable and breaks down into harmless byproducts (Singha Roy et al., 2022), it offers a safe and eco-friendly way to deliver biomolecules for crop trait engineering.

Role of surface charge

Surface charge is another critical factor that significantly influences the ability of nanocarriers to overcome the plant cell wall. Positively charged nanocarriers exhibit enhanced electrostatic interactions with the negatively charged components of the plant cell wall, promoting adhesion and facilitating entry through the narrow pores of the wall matrix (Hu et al., 2020). Recently, She et al. (2025) developed a seed-based transformation method using modified carbon dot nanoparticles functionalized with polyethyleneimine. This approach bypassed traditional tissue culture entirely by soaking cereal seeds in a solution of DNA-loaded modified carbon dot nanoparticles. This simple and effective technique resulted in consistent transient gene expression in seedlings, enabling rapid functional genomic analyses, gene function validation, expression profiling, and genome-editing applications. Remarkably, this method was successful across a wide range of plant species, both monocots and dicots, including wheat, barley, Medicago sativa, and Chinese cabbage (She et al., 2025). This rapid, tissue-culture-free system significantly accelerates crop improvement research and simplifies transformation procedures in cereals, which are traditionally considered recalcitrant species.

Size matters

Zhang et al. (2024) developed high-aspect-ratio polymeric nanocarriers, about 10 nm wide and tens to hundreds of nanometers long, designed with quaternized amine groups to confer a permanent positive charge. These carriers efficiently delivered redox-sensitive GFP and other proteins into diverse plant species, including Nicotiana benthamiana, tomato, and maize. Carriers smaller than approximately 14 nm were the most effective, consistent with the pore size of typical plant cell walls (Zhang et al., 2024). Building on this technology, Zhang et al. (2025) optimized the nanocarriers for DNA delivery, discovering that a size of around 20 nm wide and 80 nm long with a moderate positive charge (+14 mV) resulted in optimal gene expression. DNA uptake efficiency was further enhanced using mild enzymatic pre-treatment with cellulase and pectinase to disrupt the cell wall. These results demonstrated an effective strategy to break cell walls and facilitate improved delivery (Zhang et al., 2025). Simple, non-invasive methods such as seed soaking and foliar spraying of nanoparticle formulations offer an approach to rapidly advance crop research without requiring tissue culture or transgenic techniques. For example, seed nano-priming could improve germination rate, seedling vigor, and tolerance to stresses such as frost, drought, and temperature extremes. These approaches could also support high-throughput, genome-wide CRISPR screening by enabling direct delivery of guide RNA libraries into seeds or pollen, accelerating plant functional genomics.

Although many current plant nanocarrier platforms primarily rely on passive diffusion within the cytosol, conjugation with organelle-targeting peptides can direct cargo to specific organelles (Santana et al., 2020). Enzyme-driven nanomotors that enable precise navigation to specific organelles represent a potential future enhancement. Organelles produce distinct biomolecules (e.g., ATP generated by mitochondria) that can serve as endogenous cues to guide nanomotors to their targets. By incorporating enzymes that metabolize these molecules to propel nanocarriers toward regions of higher concentration, targeted delivery to specific organelles has been achieved in mammalian cells (Ortiz-Rivera et al., 2018). This approach could support the delivery of genome editors to organelle genomes. However, achieving stable and heritable genetic transformation remains a major limitation, as most nanocarrier-mediated deliveries result in transient expression. Improving the efficiency of stable integration and ensuring the heritability of genetic modifications are important priorities for future research. Furthermore, the inherent variability in cell wall composition across species, tissue types, and developmental stages may necessitate the development of customizable, context-specific nanocarrier formulations tailored to diverse plant systems.

Funding

G.A.K. would like to acknowledge funding from the Australian Research Council (DE210101200). In addition, we would like to acknowledge the Center of Sustainable Bioproducts at Deakin University.

Acknowledgments

No conflict of interest declared.

Author contributions

The authors contributed equally to the manuscript.

Published: June 19, 2025