Department of Analytical Chemistry, Faculty of Pharmacy, Gazi University, 06330 Ankara, Türkiye; Department of Civil Engineering, National University of Sciences and Technology, Quetta 24090, Balochistan, Pakistan.
Gazi University, Faculty of Science, Department of Chemistry, Ankara, Türkiye.
Bioelectrochemistry. 2024 Dec;160:108785. doi: 10.1016/j.bioelechem.2024.108785. Epub 2024 Jul 29.
This study presents a simple, fast, and sensitive label-free sensing assay for the precise enumeration of modeled pathogenic Escherichia coli K12 (E. coli K12) bacteria for the first time. The method employs the covalent binding bacteriophage technique on the surface of a reversible addition-fragmentation chain transfer (RAFT) polymer film. The Nyquist plots obtained from electrochemical impedance spectroscopy (EIS) identified the charge transfer resistance R was calculated from a suitable electrochemical circuit model through an evaluation of the relevant parameter after the immobilization of the bacteriophage and the binding of specific E. coli K12. The impedimetric biosensor reveals specific and reproducible detection with sensitivity in the linear working range of 10-10 CFU/mL, a limit of detection (LOD) of 10 CFU/mL, and a short response time of 15 min. The SERS response validates the surface roughness and interaction of the SERS-tag with E. coli K12-modified electrodes. Furthermore, the covalently immobilized active phage selectivity was proved against various non-targeting bacterial strains in the presence of targeted E.coli K12 with a result of 94 % specificity and 98 % sensitivity. Therefore, the developed phage-based electrode surface can be used as a disposable, label-free impedimetric biosensor for rapid and real-time monitoring of serum samples.
本研究首次提出了一种简单、快速、灵敏的无标记传感分析方法，用于精确计数模式化致病性大肠杆菌 K12（E. coli K12）细菌。该方法在可逆加成-断裂链转移（RAFT）聚合物膜的表面采用共价结合噬菌体技术。电化学阻抗谱（EIS）获得的奈奎斯特图确定了电荷转移电阻 R，通过评估相关参数，从合适的电化学电路模型中计算得出，该参数是在噬菌体固定和特定 E. coli K12 结合后得出的。阻抗生物传感器具有特异性和可重复性，在 10-10 CFU/mL 的线性工作范围内具有灵敏度，检测限（LOD）为 10 CFU/mL，响应时间短至 15 分钟。SERS 响应验证了 SERS 标记与修饰电极上的 E. coli K12 的表面粗糙度和相互作用。此外，在存在目标 E. coli K12 的情况下，共价固定的活性噬菌体对各种非靶向细菌菌株具有选择性，特异性为 94%，灵敏度为 98%。因此，开发的基于噬菌体的电极表面可用作一次性、无标记的阻抗生物传感器，用于快速实时监测血清样本。
