Sensors based on CNT@PSS-AuNPs/rGO layered films for portable detection of ciprofloxacin

Trace amounts of antibiotics in water can accumulate in the human body through the food chain, posing significant health risks. Therefore, there is an urgent need to develop simple and effective methods for detecting antibiotics in water. In this study, we prepared electrochemical aptamer sensors based on carbon nanotubes@polystyrene sulfonate-gold nanoparticles/reduced graphene oxide (CNT@PSS-AuNPs/rGO) layered thin films for real-time, on-site detection of ciprofloxacin (CIP) in aquaculture environments, utilizing a portable sensing detection device. The CNT@PSS-AuNPs/rGO layered film offers an excellent specific surface area, providing ample binding sites for the aptamer. The functionalized CNT@PSS-AuNPs enhance the dispersibility and conductivity of the substrate material and increase the surface area of the electrode when loaded with rGO. Under optimal experimental conditions, the developed sensor exhibits a dynamic range from 4 ng/mL to 1.0 × 10³ ng/mL and a limit of detection of 4 ng/mL (S/N = 3), demonstrating satisfactory sensitivity. The sensor also shows good stability, with a relative standard deviation of less than 1% after 100 repeated measurements. Moreover, when combined with a portable detection platform, CIP levels in aqueous environments can be analyzed intelligently, rapidly, and timely. Our study aims to promote simple and effective detection strategies, potentially extending their practical applications.