Gd3+aggregation-induced enhancement of MPA-CdTe quantum dots fluorescent probe for Tetracycline detection

In this paper, a sensitive Gd3+ aggregation-induced emission (AIE) fluorescent quantum dots probe for tetracycline detection was designed based on mercaptopropionic acid (MPA)-capped CdTe quantum dots (MPA-CdTe QDs). Gd3+ can coordinate with the carboxyl groups on the surface of MPA-CdTe QDs, which triggers the aggregation-induced enhancement fluorescence emission effect. Notably, the fluorescence of Gd3+-modified MPA-CdTe QDs (Gd3+@MPA-CdTe QDs) is quenched by tetracycline (TC). This fluorescent probe exhibits excellent selectivity and sensitivity, achieving the limit of detection of 4.26 nM. Consequently, the MPA-CdTe QDs show an "on-off" fluorescence response. Tetracycline molecule coordinates with Gd3+ in Gd3+@MPA- CdTe QDs, promoting further aggregation of the quantum dots and forming a network structure. Additionally, the inner filter effect (IFE) contributes to fluorescence quenching. The Gd3+@MPA-CdTe QDs probe can be applied for detecting TC in milk and tap water, demonstrating significant application potential. Furthermore, Gd3+@MPA-CdTe QDs can be utilized for TC detection in living cells.