Graphene oxide and UCNPs-integrated hydrogel with enhanced mechanical properties and fluorescent sensing for acetamiprid detection.

Acetamiprid pesticide residues in food have raised increasing concerns in recent years. In this study, we developed a hydrogel fluorescent biosensor integrated with graphene oxide (GO) and upconversion nanoparticles (UCNPs) for acetamiprid detection. The biosensor was constructed by embedding GO and UCNP-aptamers conjugate into a hydrogel, forming a functional platform that combines structural robustness with optical responsiveness. In the presence of acetamiprid, it rapidly bound to the UCNP-aptamer conjugate, disrupting the fluorescence resonance energy transfer (FRET) effect between GO and UCNPs, leading to fluorescence recovery. The hydrogel exhibited excellent elasticity, with a stretchability (1100 %), tensile strength (0.039 MPa), elastic modulus (0.0074 MPa), and toughness (25.27 MJ/m3). The biosensor achieved a low limit of detection (LOD) of 0.108 ng/mL, and its practical applicability for acetamiprid detection was confirmed in real tea samples, with results consistent with the standard HPLC method (p > 0.05). These findings highlight the potential of this hydrogel-based platform for the quantitative and on-site detection of pesticide residues, offering promising prospects for enhancing food safety.