A turn-on fluorescence sensor for highly selective detection of chlortetracycline based on AIE effect enhanced by citrate modified graphitic carbon nitride nanodots

In this study, the novel graphitic carbon nitride (g-C 3 N 4 ) nanodots etched with citrate (CCNDs) were synthesized successfully. And the result CCNDs exhibited an obvious aggregation emission effect (AIE) by forming a fluorescence complex with chlortetracycline (CTC) and significantly enhanced the fluorescence intensity of CCNDs. On the strength of this, the synthesized CCNDs demonstrated remarkable sensitivity and selectivity to CTC, which has been effectively studied and utilized for selectively and sensitively detecting CTC by AIE-based fluorescence-enhanced effect with a detection range spanning from 0 to 15 μM and a limit of detection (LOD) as low as 13 nM. The CCNDs were viably used for actually detecting CTC in real samples including chicken and feed, and further extended to detecting CTC in living cells. Finally, the bonding mechanism of CCNDs towards CTC was investigated in detail by dynamic light scattering (DLS), zeta(ζ) potential, TEM, ultraviolet-visible absorption spectrometry (UV-Vis), resonance light scattering (RLS) and fluorescence lifetime. It is due to the combination of a special fluorescent complex between CCNDs and CTC, which distinguishes CTC from other TCs.