Clay nanoparticles efficiently deliver small interfering RNA to intact plant leaf cells.

RNA interference is triggered in plants by the exogenous application of double-stranded RNA (dsRNA) or small interfering RNA (siRNA) to silence the expression of target genes. This approach can potentially provide insights into metabolic pathways and gene function and afford plant protection against viruses and other plant pathogens. However, the effective delivery of biomolecules such as siRNA into plant cells is difficult because of the unique barrier imposed by the plant cell wall. Here, we demonstrate that 40 nm layered double hydroxide (LDH) nanoparticles are rapidly taken up by intact Nicotiana benthamiana leaf cells and by chloroplasts, following their application via infiltration. We also describe the distribution of infiltrated LDH nanoparticles in leaves and demonstrate their translocation through the apoplast and vasculature system. Furthermore, we show that 40 nm LDH nanoparticles can greatly enhance the internalization of nucleic acids by N. benthamiana leaves to facilitate siRNA-mediated down-regulation of targeted transgene mRNA by greater than 70% within 1 day of exogenous application. Together, our results show that 40 nm LDH nanoparticle is an effective platform for delivery of siRNA into intact plant leaf cells.