Laser-driven molecular hybridization of Sm(OH)3:Se nanocomposites with tailored electronic states for antibiotics sensing

Ensuring food safety requires advanced hybrid materials capable of detecting trace antibiotics within complex plant matrices. We introduce a laser-induced molecular engineering (LIME) strategy to fabricate a selenium-integrated samarium hydroxide and graphene (Gr/Sm(OH) 3 :Se) nanocomposite engineered for direct electrochemical detection of sulfamethoxazole (SMX) in cultivated lettuce tissue. Unlike conventional laser processing techniques that primarily induce surface texturing, LIME enables molecular-level integration of functional elements, producing defect-rich interfaces with enhanced electron mobility and abundant active sites. Comprehensive characterization confirms that localized photothermal and photochemical effects promote the uniform incorporation of Se into the Sm(OH) 3 lattice and convert surface M–OH groups into M–O linkages, thereby generating holes in the O 2p valence band and improving both electron transfer kinetics and the selectivity toward SMX adsorption. The resulting sensor exhibits high sensitivity (1.83 µA (µg/g) −1 cm − 2 ), excellent selectivity, and long-term stability (> 30 days), enabling reliable trace-level detection without artificial sample spiking. Analysis of real samples further reveals higher SMX accumulation in lettuce irrigated with SMX-contaminated water. This study establishes LIME as a versatile and controllable approach for molecularly engineering electrode materials, thereby advancing the real-world monitoring of antibiotic residues in plants.