Development of a Visual Colorimetric Method for Dopamine Detection Using Gold Nanoclusters@Covalent Organic Framework as Peroxidase Mimics

Dopamine (DA) is a critical neurotransmitter linked to various neuropsychiatric disorders, emphasizing the need for precise detection in clinical settings. Herein, a novel colorimetric method for detecting DA was developed using gold nanocluster@covalent organic frameworks (AuNCs@COF) with peroxidase-like activity. The composite was created by integrating ultrasmall, uniformly distributed gold nanoclusters (AuNCs) into a COF matrix, retaining COF' advantages while enhancing catalytic activity and stability. AuNCs@COF catalyzed the oxidation of the colorless substrate TMB in the presence of H₂O₂, producing a blue product (oxTMB) with an absorbance peak at 652 nm. DA inhibited this catalytic activity, enabling visual and quantitative detection. The method demonstrated sensitivity (detection limit: 14 μmol/L) and a wide dynamic range (50–500 μmol/L), with excellent selectivity, reproducibility, and successful application in detecting DA in human urine samples (recovery rates: 93.7%–111.5%, RSD < 2.5%). This study underscores the potential of AuNCs@COF as a robust nanozyme for rapid, cost-effective, and user-friendly DA detection, holding promise for clinical diagnostics and point-of-care applications.