3D interconnected conductive network architectures of layered double hydroxides nanosheets anchored in MXene for particularly sensitive electrochemical biosensing platform

The development of precise and sensitive electrochemical sensing methods for organophosphorus pesticides (OPs) is crucial for effective contamination regulation in food and environmental resources. In this study, a novel biosensing platform, AChE-Chit/PPy/NiFe LDH/TM/GCE (APLTMG), was constructed based on the activity inhibition mechanism of the chitosan (Chit) and acetylcholinesterase (AChE) system as the biorecognition element for the rapid detection of dimethoate. The NiFe LDHs, characterized by bimetallic active sites, are deposited onto the Ti₃C₂ (TM) substrate with superior conductivity and integrated with a three-dimensional (3D) conductive network of polypyrrole (PPy). This configuration facilitates rapid charge transfer and serves to enhance performance through a synergistic effect. On this basis, the APLTMG biosensor demonstrates exceptional sensitivity with a low detection limit (1.459 × 10⁻¹¹ mol L⁻¹), good recovery rates (97.43 %–106.92 %), and reasonable relative standard deviation (RSD) or coefficient of variation (CV) (<7.8 %) for dimethoate in real samples. Besides, it is worth noting that the APLTMG exhibits the comparable repeatability, good reproducibility, stable storage performance, prominent selectivity and detection accuracy in comparison with LC-MS. This work provides valuable insights for the development of highly sensitive biosensors based on three-dimensional conductive architectures, with potential applications in ecological resource management and food safety monitoring.