A colorimetric and phosphorescent dual-mode nanosensing platform for the sensitive detection of tobramycin in dairy products

Potential tobramycin (TOB) residues in dairy products have become a concern for food safety, and their accumulation in the food chain may cause great harm to human health. Therefore, in this study, a colorimetric and phosphorescent dual-mode aptamer-sensing platform was developed. The gold nanoparticle (AuNP)-based colorimetric assay is convenient and cost-effective and can be used for semi-quantitative detection by observation with the naked eye. Zn2GeO4:Mn2+ persistent luminescent nanoparticles (PLNPs) without autofluorescence luminescence characteristics and the inner filter effect with AuNPs were introduced to realize more sensitive detection of TOB. Compared to the colorimetric mode with a detection limit of 1.04 μg L−1, the phosphorescent mode with detection limit of 2.48 × 10−3 μg L−1 has higher selectivity and sensitivity for TOB in food samples. Thus, phosphorescent detection is more than three orders of magnitude more computationally sensitive than colorimetric assays. Additionally, this sensing platform was successfully applied to actual samples such as milk, yogurt, and cheese, with 94%–106% recovery rate. This study is expected to expand the application of PLNPs in food-sensing detection, providing a new strategy for the analytical detection of antibiotic residues in food.