Europium functionalized ratiometric fluorescent transducer silicon nanoparticles based on FRET for the highly sensitive detection of tetracycline

A europium functionalized silicon nanoparticle (SiNP) ratiometric fluorescence transducer based on Fluorescence Resonance Energy Transfer (FRET) was designed to detect tetracyline (TC) as an effective antibiotic with high sensitivity and selectivity. SiNPs were prepared by one-step microwave-assisted synthesis from low-cost ethylenediaminetetraacetic acid disodium salt and (3-aminopropyl)triethoxysilane (APTES) as the precursor. The obtained SiNPs served as co-ligands for coordinating with Eu3+ ions, energy donors in FRET, and also a fluorescence reference. The fluorescence intensity ratio of I-617/I-450 of the transducer displayed a good linear response to TC concentrations in the range of 10 nM to 120 mu M with a detection limit of 5.4 nM, and was applied successfully to determine the levels of TC in normal mouse sera and milk samples with high selectivity.