Fluorescent and ratiometric probe for tetracycline antibiotics based on metal-chelated functional mesoporous silica

The need to create efficient detection techniques for tetracycline antibiotics (TCs) is pressing, as their overabundance can be damaging to ecosystems and human health. In this work, phenylterpyridine and aminopropyl functionalized mesoporous silica (APT–SBA–15) was chelated with Zn2+, and the metal-chelated functional mesoporous silica material (APT–SBA–15@Zn2+) was successfully prepared. APT-SBA-15@Zn2+ was found to be a fluorescent and ratiometric probe with remarkable selectivity and sensitivity. In the presence of TCs, the fluorescence intensity of APT–SBA–15@Zn2+ at 447 nm quenched and a new fluorescence emission appeared at 521 nm (or 512 nm), which was due to the strong interaction between TCs and Zn2+ that led to the decomposing of APT–SBA–15@Zn2+ and the formation TCs-Zn2+ complexes. The fluorescent intensity ratio at 521 nm (or 512 nm) and 447 nm versus the concentration of tetracycline (or oxytetracycline) displayed good linear relationships, realizing the ratiometric detection of TCs which can avoid interferences from background and external factors. The detection of tetracycline and oxytetracycline was limited to 76.4 and 76.2 nM, respectively.