Three MOF-Templated Carbon Nanocomposites for Potential Platforms of Enzyme Immobilization with Improved...

An efficient and facile metal-organic framework (MOF)-template strategy for preparing carbon nanocomposites has been developed. First of all, a series of metal ions, including Fe³⁺, Zr⁴⁺, and La³⁺, were respectively connected with 2-aminoterephthalate (H₂ATA) to form three metal-organic frameworks (MOFs) and then three novel MOF-derived materials were obtained by annealing them at 550 °C under N₂ atmosphere. The morphologies and microstructure results showed that they still retained the original structure of MOFs and formed carbon-supported metal oxide hybrid nanomaterials. Interestingly, it was found that La-MOF-NH₂ and its derived materials were first reported, which had wool-ball-like structure formed by many streaky-shaped particles intertwining each other. Furthermore, these MOF-derived materials were all successfully used as effective immobilization matrixes of acetylcholinesterase (AChE) to construct biosensors for the detection of methyl parathion. Especially, [La-MOF-NH₂]_N with wool-ball-like structure not only provided more active sites of multicontents to increase AChE immobilization amount but also facilitated the accessibility of electron transfer and shorten their diffusion length on the surface of electrode. Under optimal conditions, the biosensor based on [La-MOF-NH₂]_N displayed the widest linear range of 1.0 × 10^-13-5.0 × 10^-9 g mL^-1 and the lowest detection limit of 5.8 × 10^-14 g mL^-1 in three biosensors. This study illustrates the feasibility and the potential of a series of MOF-derived materials for biosensors with improved electrochemical performance.