Blue Carbon Dots Modified Cu-MOF: Excellent Peroxidase-Like Activity and Ratiometric Fluorescence Sensing to L-Cys.

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Metal-organic frameworks (MOFs) offer tunable catalytic properties.
• Carbon dots (CDs) possess unique fluorescence and redox capabilities.
• Developing efficient enzyme mimics and sensors is crucial for diagnostics.

Purpose of the Study:

• To synthesize a novel composite material (B-CDs@Cu-MOF) by integrating blue carbon dots (B-CDs) with copper-based MOF (Cu-MOF).
• To investigate the peroxidase (POD)-like catalytic activity of the composite.
• To develop a ratiometric fluorescence sensing platform for L-cysteine (L-Cys) detection.

Main Methods:

• Hydrothermal synthesis of B-CDs using citric acid and urea.
• In situ one-pot synthesis of B-CDs@Cu-MOF composite.
• Systematic investigation of POD-like activity via o-phenylenediamine (OPD) oxidation.
• Development of a ratiometric fluorescence sensor using B-CDs@Cu-MOF, OPD, and H2O2 for L-Cys detection.

Main Results:

• B-CDs were successfully incorporated into Cu-MOF without significant structural changes.
• The B-CDs@Cu-MOF composite exhibited enhanced POD-like catalytic activity compared to Cu-MOF.
• A ratiometric fluorescence sensor for L-Cys was developed with a linear range of 10–100 µmol·L−1 and a detection limit of 1.77 µmol·L−1.
• The sensor operates by L-Cys inhibiting the formation of a fluorescent product.

Conclusions:

• The B-CDs@Cu-MOF composite demonstrates superior enzyme-like catalytic performance.
• The integrated system provides an effective ratiometric fluorescence sensing platform for L-Cys.
• This work highlights the synergistic combination of MOFs and CDs for advanced sensing applications.