Hierarchical porous MXene/amino carbon nanotubes-based molecular imprinting sensor for highly sensitive and selective sensing of fisetin

In this work, a highly selective and sensitive electrochemical sensor based on hierarchical porous MXene/amino carbon nanotubes (MXene/NH2-CNTs) composite and molecularly imprinted polymer (MIP) was developed for fisetin detection. The porous MXene/NH2-CNTs films were fabricated by self-assembly of negatively charged Ti3C2Tx MXene flakes and positively charged NH2-CNTs. The utilization of conductive NH2-CNTs as interlayer spacers efficiently inhibited the aggregation of MXene flakes and formed a well-defined porous structure, as a result of increasing the effective surface area, an enhancement of the electrical conductivity and electrocatalytic activity was observed. This sensor takes advantages of molecularly imprinted technique and MXene/NH2-CNTs nanomaterials to achieve high selectivity and high sensitivity for the determination of fisetin. The factors that affect sensor response were studied and optimized. The as-prepared molecular imprinting sensor, under the optimized conditions, presented a good linear relationship with the fisetin concentration ranging from 0.003 μmol L−1 to 20.0 μmol L−1 with a limit of detection (LOD) of 1.0 nmol L−1. Besides, with favorable stability and selectivity, this newly developed sensor was utilized for the detection of fisetin in actual samples with satisfactory results.