Spatiotemporally programmable cascade hybridization of hairpin DNA in polymeric nanoframework for precise siRNA delivery

DNA nanostructures have been demonstrated as promising carriers for gene delivery. In the carrier design, spatiotemporally programmable assembly of DNA under nanoconfinement is important but has proven highly challenging due to the complexity-scalability-error of DNA. Herein, a DNA nanotechnology-based strategy via the cascade hybridization chain reaction (HCR) of DNA hairpins in polymeric nanoframework has been developed to achieve spatiotemporally programmable assembly of DNA under nanoconfinement for precise siRNA delivery. The nanoframework is prepared via precipitation polymerization with Acrydite-DNA as cross-linker. The potential energy stored in the loops of DNA hairpins can overcome the steric effect in the nanoframework, which can help initiate cascade HCR of DNA hairpins and achieve efficient siRNA loading. The designer tethering sequence between DNA and RNA guarantees a triphosadenine triggered siRNA release specifically in cellular cytoplasm. Nanoframework provides stability and ease of functionalization, which helps address the complexity-scalability-error of DNA. It is exemplified that the phenylboronate installation on nanoframework enhanced cellular uptake and smoothed the lysosomal escape. Cellular results show that the siRNA loaded nanoframework down-regulated the levels of relevant mRNA and protein. In vivo experiments show significant therapeutic efficacy of using siPLK1 loaded nanoframework to suppress tumor growth. Controlled delivery of siRNA is important for potential clinical applications. Here, the authors report on the use of cascade hybridization of DNA hairpins with ATP aptamers in DNA crosslinked polymer nanoparticles for triggered release of siRNA and demonstrate anticancer applications.

Automated summary

DNA nanostructures have been used as carriers for gene delivery, but spatiotemporally programmable assembly of DNA under nanoconfinement is challenging due to DNA complexity. A strategy using cascade hybridization chain reaction of DNA hairpins in polymeric nanoframework enables precise siRNA delivery. The nanoframework provides stability and ease of functionalization, addressing DNA complexity issues. Phenylboronate installation on nanoframework enhances cellular uptake and lysosomal escape.