Cloud-integrated microfluidic fluorescence sensing platform using UCNP/Fe3O4@Cu nanoprobes for simultaneous and on-site multi-pesticide residue detection with smartphone assistance

Rapid and efficient detection of pesticide residues is essential for ensuring food safety. Herein, we develop a smartphone-assisted multi-channel microfluidic paper–based device (MCPD) biosensor integrated with a cloud platform for the simultaneous detection of glyphosate (Gly), malathion (Mal) and acetamiprid (Ace). Detection zones are functionalised using nanoprobes fabricated via coupling up-conversion nanoparticles (UCNPs) with Fe 3 O 4 @Cu. In the presence of targets, the fluorescence intensity gradually recovers and is detected using a spectrometer and smartphone. Under optimal conditions, the MCPD exhibits a rapid response time of 25 min for Gly, Mal and Ace, with fluorescence-based detection limits of 0.133, 0.181 and 0.232 ng/mL, respectively, and image-based detection limits of 0.493, 0.346 and 0.285 ng/mL, respectively. This method shows no significant differences compared with HPLC method. Furthermore, an Android-based cloud platform enables real-time image analysis and data storage. This MCPD biosensor represents a sensitive, efficient platform for the on-site monitoring of multiple targets.