Multifunctional CuS-CDs@MnO₂ nanoparticles and liposome-assisted amplification for triple-mode detection of...

The residues of enrofloxacin (ENR) in animal-derived food and water environments have emerged as a growing public health concern in recent years. Herein, a tri-mode biosensor was designed by employing CuS-CDs@MnO₂ as the signal probe and glutathione (GSH)-loaded liposomes for amplification. The manganese dioxide (MnO₂) shell of the nanocomposite quenched the fluorescence of CuS-CDs, reduced its photothermal performance and also endowed it with oxidase-like activity. In the presence of ENR, a large amount of GSH was released after aptamer recognition and magnetic separation. Then, the shell of CuS-CDs@MnO₂ was destroyed, leading to changes in the fluorescence, colorimetric, and photothermal temperature signals. By integrating triple-mode signal output and liposome amplification, this platform enabled specific and ultrasensitive detection with the limits of detection reaching 0.543 ng mL^-1 (FL response), 30.2 ng mL^-1 (photothermal response) and 7.06 ng mL^-1 (UV-vis response), respectively. Notably, the triple-mode output of the innovative platform could enable mutual cross-validation and improve analytical reliability. Moreover, this platform exhibited satisfactory performance for ENR detection in actual spiked samples, with recoveries ranging from 92.0% to 108.9%, demonstrating promising application prospects.