Single-well colorimetric sensor array for discrimination and smartphone-assisted detection of catecholamines based on...

Catecholamines (CAs), such as noradrenaline (NE), adrenaline (AD), and dopamine (DA), are essential signaling mediators that regulate various physiological functions. Monitoring their levels is crucial for studying and diagnosing diseases, as abnormal concentrations are associated with numerous health conditions. However, distinguishing between these CAs is challenging due to their highly similar molecular structures.

In this study, Fe-doped carbon dot-based nanozymes (Fe-CDs) with strong peroxidase-like activity were synthesized using a simple one-pot method. Fe-CDs-based sensing systems exhibit excellent stability, reproducibility, sensitivity (with detection limits of 26.6 nM for NE, 46.0 nM for AD, and 33.3 nM for DA), and anti-interference properties. A triple-channel single-well colorimetric sensor array was developed by collecting the absorbance at 20, 40, and 60 min as sensing units, enabling the effective differentiation and identification of various CAs.

The Fe-CDs-based system has proven capable of detecting CAs in real human urine and fetal bovine serum. Additionally, the Fe-CDs-based smartphone-assisted platform provides efficient, highly sensitive, and on-site CAs detection, making it highly promising for biomedical and diagnostic applications.