Target-triggered surface-confined FRET on carbon dots for ratiometric fluorescence detection of acetone in exhaled breath condensate

The analysis of breath acetone could be a potential non-invasive testing alternative for routine blood-based diabetic diagnosis. However, existing methods for detecting acetone are limited by some drawbacks including complex operation, low accuracy and strong interferences from other substances in exhaled breath. Herein, we presented a straightforward ratiometric fluorescence strategy for highly efficient detection of acetone in exhaled breath condensate (EBC) based on surface-confined FRET on carbon dots (CDs). In this sensing platform, the introduction of acetone triggered specific condensation reaction with abundant phenolic hydroxyl groups around the CDs; and concurrently, the in-situ generated product constituted another emitting center by absorbing the excitation energy of the CDs, which enabled visual detection according to a remarkable fluorescence color change from blue to yellowish green. Importantly, the presented probe exhibited a highly sensitive response to acetone, a good self-calibration capability, as well as excellent selectivity against common species in EBC. Finally, it was demonstrated to be applied for accurate evaluation of the acetone content in simulated diabetic EBC samples, indicating the possibility in preliminary screening and assessment of diabetes by non-invasive breath analysis.