Bimetallic CuMo nanozyme with peroxidase-mimetic activity for sequential detecting H2O2 and DA

Dopamine (DA) as an important biomarker for assessing mood and neurological disorders, hydrogen peroxide (H 2 O 2 ) serves as a marker of oxidative stress and antimicrobial activity. The levels of DA and H 2 O 2 are associated with the development of serious neurological diseases. Therefore, precise prompt and portable detection for DA and H 2 O 2 is of great importance for clinical diagnosis and treatment, but maintaining a major challenge. In this work, bimetallic nanozyme CuMo nanosheets (CMNS) with peroxidase(POD)-like activity were fabricated by using tryptophan as ligand, and achieved sequential detection of H 2 O 2 and DA via a sequential process with limits of detection at 4.7 μM and 0.11 μM, respectively. A portable smartphone-based swab sensing system was also developed for rapid, on-site, and visual monitoring of DA with limit of detection (LOD) of 0.587 μM. This platform performed portable sensing DA with high accuracy in serum and milk samples, achieving recoveries between 93.02% and 108.2% with a relative standard deviation below 3.02%, indicated the excellent environmental tolerance. A molecular logic gate was also designed to understand and effectively apply the sequential sensing process. Overall, this work established a highly sensitive, selective, and portable colorimetric biosensing platform based on bimetallic nanozymes, demonstrated significant potential for practical application in diagnosis and biomarker monitoring. Such bimetallic nanozyme have great potential for future visible sensing in environmental and medical applications.