A Novel Dual Bacteria-Imprinted Polymer Sensor for Highly Selective and Rapid Detection of Pathogenic Bacteria

Abstract

The rapid, sensitive, and selective detection of pathogenic bacteria is of utmost importance in ensuring food safety and preventing the spread of infectious diseases. Here, we present a novel, reusable, and cost-effective impedimetric sensor based on a dual bacteria-imprinted polymer (DBIP) for the specific detection of Escherichia coli O157:H7 and Staphylococcus aureus. The DBIP sensor stands out with its remarkably short fabrication time of just 20 min, achieved through the efficient electro-polymerization of o-phenylenediamine monomer in the presence of dual bacterial templates, followed by in-situ template removal. The key structural feature of the DBIP sensor lies in the cavity-free imprinting sites, indicative of a thin layer of bacterial surface imprinting. This facilitates rapid rebinding of the target bacteria within a mere 15 min, while the sensing interface regenerates in just 10 min, enhancing the sensor's overall efficiency. A notable advantage of the DBIP sensor is its exceptional selectivity, capable of distinguishing the target bacteria from closely related bacterial strains, including different serotypes. Moreover, the sensor exhibits high sensitivity, showcasing a low detection limit of approximately 9 CFU mL^-1. The sensor's reusability further enhances its cost-effectiveness, reducing the need for frequent sensor replacements. The practicality of the DBIP sensor was demonstrated in the analysis of real apple juice samples, yielding good recoveries. The integration of quick fabrication, high selectivity, rapid response, sensitivity, and reusability makes the DBIP sensor a promising solution for monitoring pathogenic bacteria, playing a crucial role in ensuring food safety and safeguarding public health.

Keywords: Escherichia coli O157:H7; Staphylococcus aureus; bacterial detection; dual bacteria-imprinted polymer; electrochemical sensor; molecularly imprinted polymer; o-phenylenediamine.

Scheme 1

Preparation of dual bacteria-imprinted polymer (DBIP) for simultaneous capture of E. coli O157:H7 and S. aureus.

Figure 1

SEM images showing the morphological changes in the electrode surface at various stages during the preparation of the DBIP. (A) PoPD/GCE, (B,C) PoPD+dual bacteria/GCE with 5000- and 20,000-fold magnification, (D) DBIP/GCE, (E,F) DBIP-(E. coli O157:H7+S. aureus)/GCE with 1000- and 10,000-fold magnification.

Figure 2

Electrochemical characterization of the DBIP fabrication and recognition. (A–C) EIS Nyquist plots and (D) CV curves of different modified electrodes as indicated.

Figure 3

Optimization of parameters for the DBIP fabrication and bacterial recognition: (A–B) concentration of monomer and bacterial template during electro-polymerization; (C) number of polymerization cycles; (D–E) different eluents and elution time for removal of bacterial template; (F–H) recognition time, pH condition, and oscillation speed during the recognition process.

Figure 4

(A,C) EIS Nyquist plots and (B,D) corresponding calibration curves obtained from the DBIP sensor for the separate quantitative detection of E. coli O157:H7 and S. aureus over a range of concentrations from 0 to 10⁶ CFU mL⁻¹.

Figure 5

Selectivity of the DBIP sensor for detection of E. coli O157:H7 and S. aureus. Mixture refers to a mixed bacterial solution of E. coli O6 and S. hemolyticus. Each bacterium in the different samples was kept at the same concentration of 10⁵ CFU mL⁻¹.

Figure 6

Reusability of the DBIP sensor for bacteria detection.