LSPR-based Colorimetric Biosensor Design for Effective Immunodetection of Vibrio Cholerae O1

Cholera is a known intestinal infection caused by toxigenic bacteria called Vibrio cholera and is a global threat to public health. Therefore, achieving accurate and affordable diagnostic management is challenging. In this study, a colorimetric-based immunoassay has been developed to direct the detection of V. cholerae O1. Initially, the gold nanoparticles synthesis program and its polyclonal antibody-based electrostatic surface modification were managed by dynamic light scattering (DLS), Zeta potential (Zp), and Ultraviolet (UV)-visible spectroscopy. Finally, Localized Surface Plasmon Resonance (LSPR) monitoring and plasmonic nanoprobes color-changing were evaluated in the presence of different concentrations of V. cholerae O1 and its related bacteria. Accordingly, the detection range of the designed LSPR-biosensor was evaluated by significantly reduced absorption and redshift of 5 nm via increasing the antigen concentration from 10 to 103 CFU/ ml. In addition, the visible color-changing of the nanoprobe suspension was confirmed for all vials containing the target antigen in less than 1 hour. Meanwhile, there was also a significant shift for V. cholerae O1 bacteria via reducing the power of absorbance in comparison to typically intestinal bacteria. In conclusion, we suggest our colorimetric biosensor can enhance the accurate monitoring of V. cholerae O1 to limit the unexpected spread of the cholera epidemic.