OICC Press Journal of Nanostructure in Chemistry 2193-8865 15 4 2025 08 31 Pretreatment-Free Rapid Detection of Tiamulin in Egg and Milk Samples using Gold Nanoparticles Based on Positive List System Regulations 10.57647/jnsc.2025.1504.15 EN Munirah Alhammadi Department of Biological Sciences and Bioengineering, Inha University, Incheon, Republic of Korea Sonam Sonwal Department of Biological Sciences and Bioengineering, Inha University, Incheon, Republic of Korea Soobin Han Department of Biological Sciences and Bioengineering, Inha University, Incheon, Republic of Korea Hanseung Kim Department of Biological Sciences and Bioengineering, Inha University, Incheon, Republic of Korea Dong-Hwan Kim School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea https://orcid.org/0000-0002-2753-0955 Mi-Hwa Oh National Institute of Animal Science, Rural Development Administration, Wanju, South Korea https://orcid.org/0000-0001-7838-5260 Yun Suk Huh Department of Biological Sciences and Bioengineering, Inha University, Incheon, Republic of Korea https://orcid.org/0000-0003-1612-4473 Journal Article 2025 08 31 Tiamulin (TML) antibiotic residues in animal products could pose potential health hazards to consumers. South Korea set the positive list system regulations, where the maximum residue limits of TML in poultry eggs should not exceed 1000 ng/mL. Therefore, we developed a simple and pretreatment-free lateral flow immunoassay based on a highly specific TML antibody conjugated with gold nanoparticles for qualitative and semi-quantitative analysis of TML. The optimized sensor showed a visual limit of detection of 15 ng/mL for both milk- and egg-spiked samples, with a cut-off value of 100 ng/mL and 180 ng/mL for milk and egg, respectively. The assay demonstrated high recovery in both milk and egg matrices with relative standard deviation values below 12%, confirming its suitability for rapid and reliable determination of TML in complex food samples. As both sample types required no pretreatment and provided visible results within 10 minutes, the sensor is simple, user-friendly, and highly tolerant to matrix interferences. Moreover, it exhibited specific selectivity toward TML, supporting its potential as a promising detection platform for monitoring TML in animal products.