Covalent Organic Frameworks with Fe/Co Single-Atom Nanozyme for Alendronate Sodium Detection

Constructing nanozyme-based single atoms with exposed metal-Nx catalytic sites for alendronate sodium (ALDS) tablet quality control is a complex and uncommon task. Herein, we presented an innovative colorimetric assay to detect ALDS utilizing carbon-supported Fe/Co dual-atom nanozymes (Fe/CoSA-NCs) derived from a precursor of porphyrin covalent organic frameworks (COFs). The Fe/CoSA-NC nanozymes, featuring an Fe–N5 active site and electronic interactions between Fe and Co, exhibited enhanced peroxidase-like activity. Experimental findings and theoretical calculations elucidated that the superior activity of Fe/CoSA-NCs stemmed from the synergistic effect of the dual atoms, which boosted substrate adsorption and reduced the reaction barrier. When integrated with ALDS and Fe/CoSA-NCs, the peroxidase-like activity of Fe/CoSA-NCs could be inhibited due to ALDS-Fe3+ coordination. Leveraging this mechanism, a rapid and selective colorimetric method was developed for detecting ALDS. The Fe/CoSA-NC sensor showed a detection limit of 0.96 μM for ALDS in phosphate buffer, surpassing traditional techniques in terms of efficiency, accuracy, and simplicity. Moreover, the system was successfully utilized to control the pharmaceutical quality of ALDS and to determine ALDS in urine samples. This work opens a powerful avenue for developing efficient dual-atom nanozymes from COFs and expands the potential applications of nanozyme clinical pharmacy.