Aptamer-Based Fluorescent Biosensors for Kanamycin Detection in Food Systems: Design Strategies, Sensing Mechanisms, and Practical Applications.

Kanamycin (KANA), a widely used aminoglycoside antibiotic in animal husbandry, is associated with residue accumulation in foods due to improper use, threatening food safety. Detecting trace KANA in complex food systems such as dairy, meat, and apicutural products remains challenging because of matrix interferences (e.g., proteins, lipids, and co-existing ions) and limitations of conventional methods, which require labor-intensive pretreatment and sophisticated instrumentation. Aptamer-based fluorescent biosensors have emerged as promising tools for rapid, sensitive KANA detection with high specificity and on-site analysis potential. DNA aptamers act as selective recognition elements that bind KANA and undergo conformational changes for efficient signal transduction. This review summarizes recent advances in fluorescent aptasensors for KANA detection, with an emphasis on food system applications. Aptamer selection strategies are outlined, highlighting split aptamers' advantages in binding precision and structural stability. Labeled and label-free sensing modes are compared in terms of design principles, analytical performance, and suitability for complex food matrices. Attention is paid to strategies for mitigating matrix interference and improving detection reliability in real samples. Despite progress, challenges remain in sensor stability, reproducibility, and on-site deployment. Overall, aptamer-based fluorescent biosensors provide a powerful platform for rapid antibiotic residue monitoring and advance food safety-oriented sensing technologies.