A copper(II) phthalocyanine-based metallo-covalent organic framework decorated with silver nanoparticle for sensitively detecting nitric oxide released from cancer cells

[Display omitted] •Metallo-copper phthalocyanine-based COF doped with silver nanoparticles (CuTAPc-MCOF@AgNPs) was prepared.•The CuTAPc-MCOF@AgNPs showed excellent electrocatalytic activity for NO electro-oxidation.•The proposed electrochemical sensor showed a high sensitivity and low detection limit toward NO.•The sensor was applied for the in situ detection of NO released from living cancer cells. A novel metallo-copper phthalocyanine-based covalent-organic framework (CuTAPc-MCOF) doped with silver nanoparticles (denoted as CuTAPc-MCOF@AgNPs) was developed. CuTAPc-MCOF was synthesized using Cu(II) 4′,4′′,4′′′,4′′′′-tetra-amine phthalocyanine (CuTAPc) and 2,9-bis[p-(formyl)phenyl]-1,10-phenanthroline as building blocks through the Schiff base condensation reaction. The basic characterizations revealed that CuTAPc-MCOF demonstrated extended π-system and possessed the phenanthroline group, which can be coordinated with Ag. Consequently, it endowed the CuTAPc-MCOF@AgNPs nanohybrid with good biological compatibility, boosted electron transfer, and produced abundant catalytic active sites. As such, the CuTAPc-MCOF@AgNPs nanohybrid illustrated superior biocompatibility and excellent electrocatalytic activity, thereby showing remarkable electrocatalytic performance for electro-oxidizing nitric oxide (NO) released from living cancer cells. The sensing properties of the CuTAPc-MCOF@AgNPs-based sensor were measured by cyclic voltammetry and amperometry techniques. The CuTAPc-MCOF@AgNPs-based electrochemical sensor showed a high sensitivity of 29.1 μA μM−1 cm−2 and a low detection limit of 12.6 nM within the concentration range of 0.18 μM to 17.1 μM toward NO, together with excellent selectivity, high reproducibility and repeatability, and good stability. Overall, our sensing strategy showed potential application in detecting NO released from living cancer cells and diagnosing biological processes.