A Dual-Mode On-Chip 3D-Printed Nanoengineered Platform for Extraction and Electrochemical Detection of Enrofloxacin.

A magnetic molecularly imprinted polymer (MMIP) is synthesized for the development of a highly selective and sensitive electrochemical sensing platform targeting enrofloxacin (ENF). The micro-sized mesoporous core-shell MMIP structure is constructed with a magnetite core and an outer shell functionalized using 3-aminopropyltriethoxysilane (APTES) as the monomer. The synthesis is optimized and validated using a range of physical and electrochemical techniques. The sensor is designed with dual-mode functionality, integrating magnetic separation for efficient target extraction and electrochemical detection for precise quantification. A conventional electrode is modulated with multi-layer nano-functionalization to improve its analytical performance, while 3D-printed components ensure miniaturization, fabrication precision, and scalability. The resulting device exhibits a broad linear detection range from 100 pM to 10 mM (10 to 10 M), with an exceptionally low limit of detection (LOD) of 161 fM (1.61 × 10 M). As ENF is recurrently administered to cattle, milk is used as a real sample to demonstrate the sensor's proof-of-application. Real sample analysis showed a high recovery rate (90.23% to 97.29%) with minimal matrix interference, confirming reliability in complex biological matrices. The platform demonstrates exceptional reproducibility and stability, offering a robust and scalable solution for environmental and food safety monitoring.