Ultrasound-assisted gram-scale synthesis of nano-tubular ag-MOF and its hybridization with yellow/green carbon quantum dots: membrane-based turn-on fluorescence recognition for procaterol.

Procaterol, a third-generation long-acting β₂-adrenergic receptor agonist, is widely used in asthma and chronic obstructive pulmonary disease (COPD) treatment. Rapid and sensitive detection of Procaterol is essential for both clinical monitoring and environmental surveillance. This study presents a facile and gram-scale synthesis of tubular silver-based Metal-organic framework (MOF) MONT by employing an ultrasonic-assisted green synthesis strategy (20 kHz ultrasound, 100 W power, 30 min). Meanwhile, carbon quantum dots (CQDs) that emit yellow or green fluorescence can be synthesized by the hydrothermal method and dialysis purification. These two materials were hybridized to construct an Ag-MOF/CQDs hybrid material system, and further detection systems based on MONT@Y-CDs and MONT@G-CDs were developed. In the composite system, MONT can interact with procaterol and transfers energy to CQDs, amplifying the fluorescent detection signal, which enables highly efficient procaterol detection with detection limit to 17.63 nM and detection sensitivity (2.66 × 103 M-1) superior to other materials. Moreover, mixed matrix membranes based on Ag-MOF@CQDs have been prepared. As the concentration of procaterol increases, the membrane exhibits a gradual color change from blue to cyan under UV light, offering a visual method for on-site rapid screening. This study integrates ultrasonic synthesis, gram-scale amplification and functional membrane design, addressing key issues of low synthesis efficiency, scalability difficulties, and insufficient detection visualization of MONT materials. The developed detection system, with its high sensitivity and fast response, provides an innovative solution for real-time monitoring of β₂-receptor agonists like procaterol, as well as for drug quality control and environmental pollution prevention and control.