A novel ratiometric nanoprobe based on copper nanoclusters and graphitic carbon nitride nanosheets using Ce(III) as crosslinking agent and aggregation-induced effect initiator for sensitive detection of hydrogen peroxide and glucose

Herein, glutathione-capped copper nanoclusters (CuNCs) and graphitic carbon nitride nanosheets (g-C 3 N 4 NSs) were synthesized by a facile one-pot chemical reduction and directly thermal pyrolysis following ultrasonic exfoliation approaches, respectively. The introduction of Ce(III) (Ce 3+ ) played dual functions in constructing a fluorescence-enhanced ratiometric nanoprobe (g-C 3 N 4 NSs-Ce 3+ -CuNCs), i.e., triggering aggregation-induced emission of CuNCs and conjugating g-C 3 N 4 NSs with CuNCs by virtue of electrostatic and coordination interactions. The as-fabricated nanohybrid displayed 460 and 625 nm dual-emitting peaks, attributing to the emission of g-C 3 N 4 NSs and CuNCs, respectively. Upon addition of H 2 O 2 , the 625 nm emission was dramatically quenched, whereas the 460 nm emission remained nearly unchanged, thereby causing obvious color changes from purple to blue under a 365-nm UV lamp. A ratiometric fluorescent assay, based on g-C 3 N 4 NSs-Ce 3+ -CuNCs, was devised for sensitive and visual detection of H 2 O 2 , which spanned the linear range of 2–100 μM with a detection limit of 0.6 μM. In the presence of glucose oxidase , the ratiometric nanoprobe could be simultaneously employed to detect glucose across the linear range of 1.6–320 μM with a detection limit of 0.48 μM. In milk and human serum samples, the fortified recoveries for H 2 O 2 and glucose by the nanoprobe were in the range of 95.5–103.6% with RSDs <3.8%. The real detection levels for glucose are consistent with those by a standard glucometer. As such, the ratiometric nanoprobe offers a promising methodology for several practical applications, such as point-of-care diagnosis and workplace health evaluations.