SiO2-MIP core-shell nanoparticles containing gold nanoclusters for sensitive fluorescence detection of the antibiotic erythromycin

The authors describe a fluorescence based assay for determination of the macrolid antibiotic erythromycin (ERY). It is based in the use of fluorescent gold nanoclusters (AuNCs) coated first with silica (to obtain AuNC@SiO2) and then with a molecularly imprinted polymer (MIP). The MIP was synthesized from 3-aminopropyltriethoxysilane as the functional monomer, ERY as the template, and tetraethoxysilane as the cross-linker via a sol-gel process that leads to surface imprinting. By using this method, the strong fluorescence of AuNCs was maintained in the resultant MIPs. After optimization of the experimental conditions, the signal (measured at excitation/emission wavelengths of 396/585 nm) decreases linearly with increasing concentration of ERY in the 0.1 to 11.9 μM ERY concentration range. The limit of detection is 12 nM, and the imprinting factor is 4.0. The method was successfuly applied to the determination of ERY in spiked human urine and saliva.