Construction a novel photoelectrochemical aptasensor based on multivariate copper-based metal-organic framework for...

Chronic tetracycline (TET) exposure in water/food triggers drug resistance, immune damage and allergies, requiring rapid, sensitive TET detection to safeguard food and human safety. Herein, a novel photoelectric active multivariate copper-based metal-organic framework (Cu-MOF) constructed from tetra(4-carboxyphenyl)porphine (TCPP) and 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) (denoted as Cu-TCPP/TPyP) was employed as the bioplatform for the fabrication of a photoelectrochemical (PEC) aptasensor for the efficient detection of TET. The Cu-TCPP/TPyP was synthesized via the coprecipitation method using TCPP and TPyP as dual ligands and copper ions as the metal precursor. Due to the dual-coordination metal nodes, the attained Cu-TCPP/TPyP possessed rich defects, large pore size, and high specific surface area relative to Cu-MOFs prepared using the sole ligand. The Cu-TCPP/TPyP also showed enhanced photoelectric conversion efficiency due to the suppressed combination of electron-hole pair, enhanced visible light utilization, and high carrier density. The manufactured Cu-TCPP/TPyP-based PEC aptasensor thus exhibited the ultralow limit of detection of 0.76 fg mL^-1 toward TET within the concentration from 1 fg mL^-1 to 10 ng mL^-1, markedly lower than most reported TET biosensors. In view of the high selectivity, good reproducibility, and high long-term stability, the constructed aptasensor possesses wide practicability for the sensitive determination of TET in diverse samples, which was also confirmed by the standard conventional determination method. The presented PEC aptasensor puts forward the advancement of the MOF-based biosensor in the field of the analysis of food safety.