摘要
MXene-derived Ti 3 C 2 quantum dots have recently emerged as a promising sensing probe owing to their excellent optical properties. In this study, nitrogen-doped MXene-derived Ti 3 C 2 quantum dots (N-MQDs) were synthesized by cutting ultrathin Ti 3 C 2 MXene nanosheets with the assistance of ammonia via a hydrothermal method. The optimal synthesis conditions for N-MQDs, including reaction temperature, time, and initial concentration of precursor, were systematically investigated. The as-synthesized N-MQDs exhibit excitation-dependent fluorescence, with maximum emission fluorescence observed at 420 nm. In addition, various experiments, including long-term storage, UV exposure, temperature variations, and a wide range of pH levels, were conducted to validate the remarkable stability of N-MQDs. The relationship between the quenching levels of N-MQDs and tetracycline (TC) concentration across a range of 0.50–300 µM was well-fitted to the modified Stern–Volmer equation, yielding a low limit of detection (LOD) of 24 nM. Furthermore, superior selectivity was demonstrated over 20 interfering compounds, including various inorganic ions, common biomolecules, and other antibiotics. A possible mechanism for TC detection by N-MQDs is proposed, highlighting the notable contribution of “dark” complex formation between N-MQDs and TC, with considerable involvement of Förster resonance energy transfer (FRET) and inner filter effect (IFE). Subsequently, N-MQDs were successfully applied to detect TC in human serum, achieving satisfactory recovery rates. These results clearly demonstrate the potential applicability of N-MQDs for TC detection, paving the way for enhanced fluorescence applications of N-MQDs in biosensing.