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چکیده
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This study introduces a novel electrochemical biosensor developed for the selective and sensitive detection of Staphylococcus epidermidis (S. epidermidis). Unlike conventional biosensors that employ nanocomposite modifiers, the proposed sensor was fabricated without any nanomaterial coatings. Lignin, a natural and biocompatible polymer rich in functional groups, was used as the structural matrix for bacterial imprinting. Through an electropolymerization process, the lignin layer was stabilized on the electrode surface, forming specific recognition cavities complementary to S. epidermidis. After removal of the bacterial template, the modified electrode served as the sensing interface. The electrochemical behavior of the prepared biosensor was evaluated using cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS). Upon exposure to S. epidermidis, a distinct change in current signal was observed, confirming the successful rebinding of the target bacteria within the imprinted cavities. The biosensor exhibited a linear detection range from 1.0 × 101 to 1.0 × 107 CFU/mL with a detection limit of 3.03 CFU/mL. Relative to a non-imprinted electrode, the imprinted system demonstrated enhanced selectivity and sensitivity. Under the optimum conditions, the sensor was effectively applied for detecting S. epidermidis in human urine and serum samples, demonstrating excellent accuracy, repeatability, and recovery performance.
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