A novel electrochemical chiral interface based on sandwich-structured molecularly imprinted SiO2/AuNPs/SiO2 for enantioselective recognition of cysteine isomers

SiO 2 nanospheres were synthesized by the sol–gel method using tetraethoxysilane (TEOS) as the precursor, which was then modified with 3-aminopropyltriethoxysilane (APTES) for the grafting of NH 2 to the SiO 2 surface. Au nanoparticles (AuNPs) were anchored to the NH 2 grafted SiO 2 , and then l -cysteine (L-Cys) templates were introduced to the SiO 2 /AuNPs through forming Au S bond. Another layer of SiO 2 was then coated on the L-Cys doped SiO 2 /AuNPs as the coating layer, and then the templates were removed by calcination to form a sandwich-structured molecularly imprinted SiO 2 /AuNPs/SiO 2 . Finally, the molecularly imprinted chiral interface was applied for electrochemical enantioselective recognition of Cys isomers, and discernible differences in the current signals could be observed on the differential pulse voltammograms ( I D-cys / I L-cys , 2.36).