The synthesis of PEI core@silica shell nanoparticles and its application for sensitive electrochemical detecting mi-RNA

Abstract

Although the silica-based nanoparticles (NPs) have been widely explored as the labels for sensing different targets, the simple and novel scheme, to impose a large number of signal molecules inside silica NPs, is challenge. Herein, a new scheme for this purpose was developed. This new strategy was based on densely doped polyethyleneimine (PEI) inside silica nanoparticles and forming the PEI@silica nanoparticles. Then, the Cu2+ was selected as the electrochemical signal molecule model to be loaded in PEI@silica nanoparticles the based on the strong coordination reaction of Cu2+ with PEI and test its signal amplification ability. Our results showed that 7.6 × 105 Cu2+signal ions could be loaded in a single PEI@silica nanoparticles. Thereafter, based on the discriminating interaction of this PEI/Cu2+/SiO2 NPs towards both ssDNA probes and ssDNA probe/mi-RNA complex, as well as the specific adsorption effect of this NPs on chemically modified electrode, a highly sensitive electrochemical method for detecting mi-RNA was developed and successfully used to detect mi-RNA in the human serum samples.