Fabrication of ultrasensitive ciprofloxacin electrochemical aptasensor based on AuNPs decorated MWCNTs@GO@CS film

MWCNTs@GO@CS film enhances aptamer binding and sensor stability. • Wide linear range (0.03–100.00 nM) with 0.01 nM LOD. • The sensor exhibits simplicity, accurate for CIP detection in real samples. • It has potential application value in on-site analysis. A highly sensitive electrochemical aptasensor (BSA/Apt/MWCNTs@GO@CS/. AuNPs/SPCE) was fabricated for the efficient detection of ciprofloxacin (CIP). The complementary structural and physicochemical properties of MWCNTs and GO provide a conductive and functionalized platform for aptamer immobilization, while the excellent film-forming property of CS ensures stable and uniform deposition of the nanomaterials on the limited SPCE surface. The sensor displayed excellent linearity by the DPV method from 0.03 to 100.00 nM with a detection limit of 0.01 nmol/L. Spiked recovery tests in lake water and river water achieved 97.98–103.98% recovery with relative standard deviations below 10%, indicating acceptable precision. Moreover, results from chicken samples analyzed by the proposed sensor were consistent with HPLC-MS, with only 0.9% relative error, confirming the sensor's reliability and practical applicability for real-world CIP monitoring. Scheme 1. (A) Fabrication process of the BSA/Apt/MWCNTs@GO@CS/AuNPs/SPCE sensor; (B) The detection process of CIP in real samples. Download: Download high-res image (134KB) Download: Download full-size image