Ultra-thin silica shell-guarded nanoflares for high-fidelity live cell miRNA-21 imaging by fully avoiding the interference of biothiols.

We successfully constructed a new class of nanoflares based on ultra-thin silica-coated gold nanoparticles (Au@SiO 2 ) with the covalent binding of nucleic acids, which demonstrated more resistance to biothiols than that exhibited in the traditional Au-S binding strategy, for imaging the target miRNA-21 with high fidelity in living cells.