Fast cathodic electrodeposition of ZnTCPP-functionalized metal-organic framework films for preparation of a fluorescent aptamer sensor for microcystin determination.

A one-step electrodeposition-assisted self-assembly technique has been developed for preparation of ZnTCPP@MOF films with three-dimensional mesoporous structure in a three-electrode system. The internal structure of the ZnTCPP@MOF films was tuned by adjusting the electrochemical deposition voltage, deposition time, and the concentration of ZnTCPP at room temperature. The ZnTCPP@MOF films under different deposition conditions were characterized by scanning electron microscopy, Fourier transformation infrared spectroscopy, and X-ray photoelectron spectroscopy. The prepared ZnTCPP@MOF films exhibited excellent fluorescence properties, in which ZnTCPP molecules were encapsulated inside the MOF as fluorescent signal probes and structure-directing agents, which affected the electrochemical response of the ZnTCPP@MOF films. The sensing platform based on ZnTCPP@MOF film was used to detect microcystin with a wide determination range (1.0 × 10 -12  mol/L ~ 1.0 × 10 -5  mol/L), low determination limit (3.8 × 10 -13  mol/L), and high sensitivity. More importantly, the strategy is simple, low-cost, green, and environmentally friendly, and it provides a new strategy for the direct use of MOFs films as signaling components.