Comparative Study of Electrochemical Biosensors Based on Highly Efficient Mesoporous ZrO₂-Ag-G-SiO₂ and In₂O₃-G-SiO₂ for Rapid Recognition of <i>E. coli</i> <i>O157:H7</i>

Abstract

Here, we reported an innovative and electrochemical biosensor for the rapid detection of <i>Escherichia coli</i> <i>O157:H</i>7. We fabricated the mesoporous ZrO₂-Ag-G-SiO₂ (ZAGS) and In₂O₃-G-SiO₂ (IGS) sensors, and cyclic voltammetry (CV) was employed to detect the bacteria. The development of these portable sensors addresses the challenges of conventional time-consuming and more expensive laboratory-based analyses. Hence, the biosensors were highly selective to detect <i>E. coli</i>. The sensor could recognize an individual <i>E. coli</i> cell in 1 μL of sample volume within 30 s. <i>E. coli</i> live cells tied down on sample nanoparticles worked toward the definite acquirement of <i>E. coli</i>. The high thickness of negative charge on the surface of <i>E. coli</i> cells effectively regulated the concentration of dominant part charge carriers in the mesoporous channel, allowing a continuous check of <i>E. coli</i> concentration in a known sample. The signal current decreased linearly, while the <i>E. coli</i> concentration increased from 1.0 × 10¹ to 1.0 × 10¹⁰ CFU/mL. ZAGS and IGS biosensors could detect <i>E. coli</i> in the range from 10¹ to 10¹⁰ CFU/mL. ZAGS and IGS biosensors in this investigation showed great specificity, reproducibility, stability, and selectivity and are expected to have a great impact on applications in the detection of foodborne pathogens.