Delaminated layered double hydroxide delivers DNA molecules as sandwich nanostructure into cells via a non-endocytic pathway

Layered double hydroxides (LDHs) are effective molecular carriers in cytological research, gene therapy, and transgenic applications. Herein, we investigated the internalization behavior of the LDH-DNA bioconjugates via a microscopic approach and analyzed the internalization pathway by dissipative particle dynamics (DPD) simulations. We experimentally found that LDH can efficiently carry DNA into the nucleus of cell in BY-2 suspension cells. Furthermore, atomic force microscopy and X-ray diffraction analysis demonstrated that the LDH-DNA bioconjugates mainly exist as a DNA-LDH-DNA sandwich complex, while the LDH-DNA-LDH sandwich complex and DNA-LDH complex cannot be excluded. The DPD simulations further indicated that only the DNA-LDH-DNA sandwich structure could penetrate the plasma membrane (PM), while PM is impermeable to the LDH-DNA-LDH sandwich complex and the DNA-LDH complex. This work provides novel perspective for understanding the membrane penetration mechanism of LDH nano-sheets and new insights into the design of novel molecular delivery systems.