Automatic magnetofluid-integrated microfluidic biosensing platform for dual-colorimetric analysis of organophosphorus...

Excessive pesticide residues in crops pose a serious threat to food safety and human health, necessitating simple and reliable detection methods. This work presents an automated microfluidic biosensing platform integrated with magnetofluid for dual-color detection of organophosphorus pesticides. The system utilizes acetylcholinesterase (AChE)-mediated aggregation of gold nanoparticles to generate colorimetric signals. An Arduino-controlled stepping motor drives a magnet to precisely manipulate AChE-functionalized magnetic beads within the microchannel, enabling automated target recognition, washing, and detection. A portable RGB sensor connected to the Arduino quantifies the color changes. The device achieves a low detection limit of 0.012 μg/mL for malathion within 22 min, with a linear range of 0.02-1.5 μg/mL. Furthermore, this detection method also demonstrates wide applicability and exhibits excellent detection performance for pesticide residues in various food matrices. This platform offers an innovative approach for automated, sensitive, and user-friendly pesticide residue monitoring.