A cascade-triggered ratiometric fluorescent sensor based on nanocomposite for lactate determination

For this study, a cascade-triggered ratiometric fluorescent sensor based on nanocomposites was designed to detect lactate. This sensor was established by breaking the inner-filter effect (IFE) between blue emission carbon dots (bCDs) and silver nanoparticles (AgNPs) and activating the dynamic quenching process of red emission quantum dots (rQDs) and Ag+. In this sensor (bCDs/AgNPs-rQDs), the fluorescence of bCDs was quenched by the formation of CDs/AgNPs, and recovered by adding lactate. Subsequently, the quenching of rQDs was triggered by Ag+, which originated from the disintegration of AgNPs. This cascade-triggered ratiometric fluorescent sensor for lactate detection was established with the LOD (limit of detection) of 0.12 μM. The developed probe was applied to lactate detection in human serum with satisfactory results, indicating that the probe has enormous potential in clinical practice.