Modification of polyacrylonitrile-derived carbon nanofibers and bacteriophages on screen-printed electrodes: A portable electrochemical biosensor for rapid detection of Escherichia coli
圖文摘要說明
這張圖片展示了一種基於噬菌體的一次性電化學生物感測器的製備和應用流程，用於檢測大腸桿菌（E. coli）。圖中左側列出了感測器的各個組分：絲網印刷電極（SPE）、噬菌體、碳納米纖維（CNF）和氧化還原探針[Fe(CN)6]3-/4-。製備過程包括在裸露的 SPE 上滴塗碳納米纖維（CNF/SPE），以增加表面積並維持導電性，然後固定化大腸桿菌噬菌體（phage/CNF/SPE）。當目標大腸桿菌與固定在電極表面的噬菌體結合時（E. coli/phage/CNF/SPE），會阻礙電極表面的電子傳遞，導致電化學阻抗譜（EIS）測量到的阻抗增加（如右下方紅色箭頭所示）。圖中顯示的 EIS 圖譜反映了不同修飾階段電極的阻抗變化。這個生物感測器旨在快速、靈敏地檢測食品等樣品中的大腸桿菌。
Abstract
A disposable electrochemical biosensor for the rapid detection of Escherichia coli (E. coli) was fabricated by modifying screen-printed electrodes (SPEs) with polyacrylonitrile-derived carbon nanofibers (CNFs) and bacteriophages. To amplify the signal response of the electrochemical biosensor, CNFs were drop-coated on the bare SPEs to increase the surface area and maintain conductivity. After modification with CNFs, E. coli phages were immobilized on the CNF-modified SPEs by physical adsorption. The binding of E. coli to the phages on the electrode surface blocked the electron transfer of the redox probe [Fe(CN)6]3−/4−, resulting in an increase in the impedance, which was measured by electrochemical impedance spectroscopy (EIS). The fabricated biosensor (phage/CNF/SPE) was characterized by scanning electron microscopy, contact angle measurements, and EIS. The biosensor exhibited a wide linear range of 102 to 107 CFU/mL and a low limit of detection of 10 CFU/mL. Furthermore, the biosensor showed high specificity for E. coli and was successfully used for the detection of E. coli in real food samples (milk and apple juice). The developed electrochemical biosensor is disposable, portable, low-cost, and easy to operate, and it shows potential for the rapid screening of E. coli in food samples.
Keywords：Electrochemical biosensor; Bacteriophage; Carbon nanofiber; Escherichia coli; Screen-printed electrode
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