An imprinted Ag@CdS core shell nanoparticle based optical-electrochemical dual probe for trace level recognition of...

In this work, we present a new approach to prepare the Ag@CdS core-shell fluorescent nanoparticles wrapped with molecularly imprinted polymer for ferritin macromolecule by capping with vinyl derivative of cysteine. The imprinted Ag@CdS nanoparticle was prepared via activator regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP) method onto the surface of vinyl silane modified pencil graphite electrode. Combination of Ag and CdS in a single motif causes the dual behavior of core shell nanoparticle, which shows enhanced fluorescence as well as electrochemical properties. The performance of the obtained imprinted sensor was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, chronocoulometry, differential pulse voltammetry and fluorescence spectrophotometry. Under the optimal experimental conditions, the current response of the electrochemical sensor was linear to ferritin concentrations in the range from 1.99 to 23.43 µg L⁻¹, with the detection limit of 0.65 µg L⁻¹. Similarly, a linear response was obtained between fluorescence quenching of imprinted Ag@CdS and concentration of ferritin in the range from 4.0 to 91.0 µg L⁻¹, with limit of detection (LOD) of 1.3 µg L⁻¹. The method was successfully applied to the analysis of blood serum samples of five different men and women with acceptable recoveries of 99.7% and 100.3% (RSD in %=1.0-2.0).