Poly (ionic liquid) cross-linked hydrogel encapsulated with AuPt nanozymes for the smartphone-based colorimetric...

A poly (ionic liquid) enhanced poly(acrylamide-acrylic acid) (PIL-PAM/AA) hydrogel-based colorimetric sensor was designed to detect zearalenone (ZEN). Different Au_xPt_y nanoparticles were synthesized via the on-pot method. Through the kinetic analysis and the theoretical calculation, Au_0.4Pt_0.6 possessed the relatively low energy barriers to adsorb and decompose H₂O₂ so that it exhibited relatively better catalytic activity (K_m = 2.02 × 10^-3, V_max = 6.14 × 10^-7). AuPt nanoparticles were encapsulated into PIL-PAM/AA hydrogel via the interaction between aptamer and cDNA. In the presence of ZEN, the embedded AuPt nanoparticles were released to complete the catalytic reaction. Coupled with the smartphone application, the established method provided the linear range of 1-250 ng mL^-1, with a detection limit of 0.6979 ng mL^-1 for ZEN. Meanwhile, it also possessed excellent selectivity and good anti-interference performance. In wheat and corn samples, spiked recoveries were ranging from 75% to 113.30%.