Metal-bridged DNA-functionalized silica nanoparticles for multifacet biological applications

Silicon, as the second richest element in the earth, is of great importance to the current nanoscience. Functionalization of silica nanomaterials with DNA molecules can significantly broaden their biological application. However, current assembly methods usually involve complex and time-consuming steps or detrimental reagents, limiting their real application. In this work, we report a metal ion-assistant DNA assembly method to simply, rapidly and robustly immobilize short DNA molecules on the surface of silica nanoparticles (SiNPs) and use it to perform different tasks. By fully screening the metal ions, metal ions such as Zn 2+ , Al 3+ , Y 3+ and Zr 4+ , are found to be effective on the mediation of the interaction between DNA and SiNPs. The DNA density can be finely tuned by adjusting the added concentration of DNA or metal ions, and the adsorbed DNA is highly stable in the metal ion-containing buffer. Through simply adjusting the kind of metal ions and DNA, different biological applications such as biosensing, purification, and gene regulation can be achieved. This work not only offers fundamental insights into the biointerface science of SiNPs with DNA, but holds great potential in the area of biomolecule purification, nucleic acid delivery, biosensing, and bioimaging.