An electrochemical aptasensor for streptomycin based on covalent attachment of the aptamer onto amesoporous silica thin film-coated gold electrode.

Abstract

An electrochemical method is described for the determination of streptomycin (STR). It is making use of a gold electrode coated with a thin mesoporous silica film (MSF). In addition, silver nanoparticles were coated on the MSF to increase the surface area, to bind a large amount of aptamer (Apt), and to improve the electrical conductivity. In the presence of STR, it will bind to the Apt and hinder the diffusion of the redox probe hexacyanoferrate through the nanochannels of the mesoporous film. The aptasensor, best operated at a working potential of 0.22V (vs. Ag/AgCl) has a linear response in the 1fg.mL-1 to 6.2ng.mL-1 STR concentration range. The detection limit is 0.33fg.mL-1. The assay was successfully validated by analyzing spiked samples of milk and blood serum. Graphical abstract Voltammetric assay of streptomycin (STR) by using a Fe(CN)63-/4- probe. The aptamerwas immobilized on a gold electrode modified with amesoporous silica thin film (MSF)that was functionalized with (3-aminopropyl) triethoxysilane (APTES) and silver nanoparticles (AgNP). Incubation with STR leads to adecrease of the current.