Synthesis of polyadenine-aptamer-stabilized gold nanoclusters and application to the detection of tobramycin in real samples based on their peroxidase-like activity

Tobramycin (TOB) is a widely used aminoglycoside antibiotic for treating human and animal diseases. However, its overuse poses a threat to human health, necessitating the development of a rapid and simple detection method. In this study, polyadenine-aptamer-stabilized gold nanoclusters (Ax-Apt-AuNCs) were synthesized, to investigate the impact of different polyadenine lengths on their properties. A20-Apt-AuNCs demonstrated efficient catalytic activity in the oxidation of o-phenylenediamine to 2,3-diaminophenazine (DAP) in the presence of hydrogen peroxide, resulting in yellow fluorescence emission. Upon binding specifically to the TOB aptamer on A20-Apt-AuNCs, TOB enhanced both their peroxidase-like activity and the fluorescence intensity of DAP. Based on this mechanism, a fluorescence-enhanced aptasensor was developed for TOB detection. The aptasensor exhibited a linear detection range of 10.0 nM to 1.0 mu M, with a detection limit of 2.63 nM. Furthermore, its application in real sample analysis produced satisfactory results.