Vinblastine (VLB) is prescribed for a wide variety of cancers. Therefore, development of sensitive methods for early diagnosis is urgently required. In this work, a highly sensitive and label-free impedimetric biosensor was fabricated for the electro- chemical detection of VLB. First, the gold nanoparticles (AuNPs) were electrodeposited on the surface of a glassy carbon electrode (GCE). 3-Mercaptopropionic acid (MPA) was self- assembled over the AuNPs. Then, tubulin (TUB), as a receptor, was covalently immobilized at the AuNPs/GCE surface via carbodiimide coupling reaction using N-(3 dimethy laminopropyl)-N ′ -ethyl carbodiimide (EDC) and N-hydroxy succinimide (NHS). The step-by-step modification process was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in the presence of a redox probe [Fe(CN) 6 ] 3 − /4 − . The VLB concentration was measured through the increase of impedance values in the corresponding specific binding of VLB and TUB. The increased electron-transfer resis- tance (R et ) values were proportional to the value of VLB concen- trations in the range of 0.4 to 65.0 nmol L − 1 with a detection limit of 8.4 × 10 − 2 nmol L − 1 (SN − 1 = 3). The practical analytical performance of the proposed method was demonstrated by de- termination of VLB in plant extracts and human serum samples with satisfactory recoveries.
