A highly sensitive and wide-ranged electrochemical zinc(II) aptasensor fabricated on core–shell SiO2-Pt@meso-SiO2

In this work, bi-functional SiO 2 -Pt@meso-SiO 2 core–shell nanoparticles were designed to prepare a highly sensitive and selective electrochemical zinc(II) aptasesnor. This core–shell structure boasts its SiO 2 mesoporous shell and the inside Pt nanoparticles. SiO 2 mesoporous shell can fix aptamer without affecting its configuration and can admit electrolyte through the shell. SiO 2 core inside can be the substrate of larger amount of Pt nanoparticles that improve the conductivity of the modified electrode dramatically. Due to the application of such a special bi-functional structure and the aptamer's strong combination capacity with Zn 2+ , Zn 2+ is pre-enriched onto the electrode effectively and specifically, so that it can be determined sensitively and selectively. Results have shown that the zinc(II) aptasensor can be utilized at a wide linear working range from 100   pM to 50   μM and a low detection limit of 65   pM, which makes it practical in both biological samples and environment monitoring. This method has been successfully applied in Zn 2+ monitoring in human blood and disrupted human cells (MCF-7).