Synthesis of BiC@Au@Apta by electrospinning as an electrochemical sensor for detection of tetracycline

As a broad-spectrum antibiotic, tetracycline (TC) is commonly employed in veterinary drugs for treating numerous diseases. Nevertheless, its residue in food and water sources poses a significant threat. Hence, there is a substantial need for a rapid, inexpensive, and simple method to detect TC in water systems. In this study, a nanocomposite sensor based on gold-modified bismuth carbide (BiC) nanofibers and connected with a TC aptamer is proposed for the detection of tetracycline. The carbonized nanofibers offer a large surface area and excellent conductivity. Gold nanoparticles (AuNPs) on the surface of BiC nanomaterials enhance the electrochemical detection performance and also serve as the binding site for the TC aptamer. The surface morphology and structure of the modified electrodes are characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical performance of BiC@Au@Apta is evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimal conditions, BiC@Au@Apta has a wide detection range (0.001–100 µM) and a limit of detection (LOD) of 2.92 nM. It also exhibits good anti-interference ability, repeatability (RSD = 2.75–2.78%), and stability ( I  = 97.30%). Additionally, BiC@Au@Apta can be utilized to detect TC in milk samples.