Highly photostable Nb2C MXene quantum dots as fluorescence probes for the quantitative specific detection of the antibiotic chloramphenicol

초록

The development of a simple, real-time fluorescence platform for the rapid and accurate detection of the essential antibiotic drug, chloramphenicol (CPL), holds great promise for use in food, environmental, and clinical diagnostics. In this work, we introduce highly luminescent, bluish-green-emitting N/S-co-doped Nb2C MXene quantum dots (Nb2C-MX QDs) synthesized through a hydrothermal process using glutathione as a nitrogen and sulfur dopant. These synthesized Nb2C-MX QDs exhibit a strong fluorescence peak at 427 nm under 330 nm excitation, making them a straightforward fluorescent nano-label for CPL sensing. Under challenging conditions such as UV light irradiation, varying ambient pH, and ionic conditions, these Nb2C-MX QDs demonstrated exceptional stability and reliability. Given QDs' outstanding properties, the fluorescence of Nb2C-MX QDs quenches significantly as a function of the dose of CPL antibiotic added to them. This notable quenching effect results from the formation of non-fluorescent complexes between the Nb2C-MX QDs and the CPL antibiotic, effectively triggering a "turn-off" fluorescence response. The proposed sensing platform has a limit of detection of approximately 76.3 nM with a detection range of 20-240 mu M. Importantly, interference tests confirm the system's high specificity, as the addition of CPL markedly suppresses the fluorescence of Nb2C-MX QDs, while other interferents, such as amino acids and other biomolecules/antibiotics, do not. Finally, this Nb2C-MX QDs quenching-based sensor was applied to estimate CPL levels in real samples, including tap water, drinking water, milk, and human blood/urine, achieving excellent signal recovery rates from 92.31 % to 98.24 %. This successful quantitative detection may tempt one to leverage Nb2C-MX QDs for real-time biosensors in point-of-care diagnosis of environmental, food, and clinical specimens.

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