ABSTRACT We present a novel, cost‐effective sensor for carcinoembryonic antigen (CEA) detection utilizing a pencil graphite electrode (PGE) in combination with electrochemical impedance spectroscopy (EIS), which offers high sensitivity and selectivity. Anti‐CEA/AuNPs/PGE was successfully illustrated as a label‐free impedimetric immunosensor for the detection of CEA. Through EIS, we observed distinct impedance changes upon CEA binding, enabling real‐time detection with high reproducibility and low interference from non‐target molecules. Due to its satisfying impedimetric response, this new immunosensor demonstrated that it can be used for high‐performance detection of CEA with a wide linear range extending from 13.2 to 1 × 10 5 pg mL −1 , with correlation coefficients ( R 2 ) of 0.9923. The PGE's excellent conductive properties and surface stability allowed for the successful detection of CEA at low concentrations, demonstrating a detection limit of 4.4 pg mL −1 , which is competitive with existing, more costly alternatives. The sensor's robust performance in spiked artificial urine samples indicates its potential for practical application in point‐of‐care cancer diagnostics, especially in resource‐limited environments. The developed electrochemical biosensor holds promise for accurately detecting CEA in urine samples, offering a precise technique that could find valuable application in clinical tumor detection.
Sazaklioglu et al. (Mon,) studied this question.