Porphyrin-functionalized glutathione-Ti3C2 MXene quantum dots for enhanced electrochemiluminescence and sensitive detection of copper ions.

(A) Schematic diagram of construction of composite MQDs-TMPyP 4. (B) Schematic diagram of the ECL biosensor based on the composite material MQDs-TMPyP 4 for Cu2+ detection and ECL mechanism. [Display omitted] • MQDs is combined with TMPyP 4 to produce composite that enhances ECL performance. • MQDs is compounded with TMPyP 4 by π-π stacking and electrostatic interaction. • MQDs-TMPyP 4 can be used to detect copper ions with high sensitivity. • The problems of low selectivity and low luminosity of MQDs in ECL field are solved. Ti 3 C 2 MXene quantum dots (MQDs) have recently gained considerable attention as promising emerging nanomaterials for biosensing applications. However, it is still in the infancy of research on the functionalisation of MQDs to improve their properties. This work synthesised glutathione (GSH)-modified MQDs by hydrothermal method and functionalised them with porphyrin (TMPyP 4), resulting in porphyrin-functionalised GSH-Ti 3 C 2 MXene quantum dots (MQDs-TMPyP 4) nanocomposite with enhanced electrochemiluminescence (ECL) properties. The lack of selectivity of MQDs and the weak luminescence intensity of ECL have been solved, expanding the method for developing materials with enhanced ECL properties. Cu2+ was found to quench the ECL luminescence of MQDs-TMPyP 4 , which is valuable for detecting copper ions. Consequently, we constructed a sensitive "Signal on–off" biosensor for Cu2+ detection. The biosensor demonstrated a sensitive response to copper ions within the concentration range of 10 nM to 10 μM, with an impressively low detection limit of 3.22 nM. Additionally, the biosensor exhibited good stability and selectivity. The ECL biosensor performed well and provided an efficient and ultra-sensitive method for detecting Cu2+. [ABSTRACT FROM AUTHOR]