Portable smartphone-assisted fluorescence-colorimetric multidimensional immunosensing microarray based on NH2-UiO-66@PtNPs multifunctional composite for efficient and visual detection of amantadine

Amantadine (AMD) is an antiviral drug used to treat animal-based infectious diseases such as avian influenza. However, its illegal use in animal-derived food industries endangers human health. Therefore, an efficient, portable, and visual sensor to detect AMD in food is crucial for ensuring food safety. A multifunctional nanocomposite NH2-UiO-66@PtNPs was exploited to design a smartphone-assisted fluorescence-colorimetric immunosensing microarray for multidimensional detection of AMD in animal-derived foods. Platinum nanoparticles (NPs) were immobilized on a Zr-based metal–organic framework (NH2-UiO-66). Pt NPs exhibited peroxidase-like activity, whereas NH2-UiO-66 stabilized Pt NPs and improved the colorimetric signal of the sensor. Moreover, the fluorescence ligand NH2-BDC in NH2-UiO-66 was released via alkaline hydrolysis, amplifying the fluorescence signal and improving detection sensitivity. The smartphone-assisted color recognition system accurately identified the color changes of the microarray. The immunocompetitive reaction of AMD and the antibody (Ab) in the microarray NH2-UiO-66@PtNPs@Ab2 allowed the quantitative and visual detection of AMD in a wide concentration range (0.1–1000 ng/mL) with high sensitivity [limit of detection = 0.0022 ng/mL (fluorescence), 0.069 ng/mL (colorimetric), and 0.68 ng/mL (smartphone)]. This detection strategy was verified in AMD-spiked food samples with satisfactory recoveries (82.0–103.0%) and stability (RSD: ≤7.1%, n = 3), showing its great potential for visual screening and portable detection of other food contaminants.