A novel carbon dots pair for the construction of a dual-channel fluorescent sensor array for discrimination and detection of biothiols.

Biothiols, such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), are crucial biomolecules involved in redox homeostasis, detoxification metabolism, and cellular signaling. Variations in their concentrations are closely linked to various diseases. However, traditional detection methods for biothiols are often complex, time-consuming, and costly. In this study, we developed a dual-channel fluorescent sensor array based on two distinct carbon dots (A-CDs and B-CDs), synthesized using citric acid and cysteine as precursors under precisely controlled preparation conditions, including the choice of oxidant and solvent. By leveraging the differential responses of A-CDs and B-CDs to biothiols and Fe as mediators, the sensor array generates specific fluorescence response fingerprints for each biothiol. Under optimal conditions, the array effectively discriminates among six biothiols, including structurally similar GSH and GSSG, with a sensitivity of 150 μM. Blind sample recognition experiments demonstrated an accuracy of 97.2 % for single biothiol samples, and practical application tests confirmed the array's ability to accurately differentiate between six biothiols in urine. This study presents an innovative and efficient method for the simultaneous detection of biothiols, highlighting its potential applications in disease diagnosis and biomarker analysis.