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

Abstract

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 H ₂O ₂ 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%.

Highlights

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  ILs-enhanced hydrogel possessed higher solubility and excellent mechanical properties.

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  DNA hydrogel encapsulated with AuPt nanoparticles could specifically and sensitively detect ZEN.

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  Au _0.4Pt _0.6 nanoparticles exhibited excellent peroxidase-like catalytic activity.

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  The theoretical calculation was used to evaluate the energy barriers of AuPt to catalyze TMB/H ₂O ₂ system.

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  The smartphone-based colorimetric sensor was successfully detected for ZEN in real samples.