LSPR-based Colorimetric Aptasensor Design for Rapid and Simple Detection of Vibrio cholerae O1

In recent years, the prevalence of intestinal diseases, particularly Vibrio cholerae, has been on the rise, leading to numerous epidemics and pandemics. To effectively manage and treat this disease, the development of a simple and fast diagnostic method is crucial. This research aims to design a colorimetric V. cholerae aptasensor using gold nanoparticles (GNPs) and the Localized Surface Plasmon Resonance (LSPR) method. A specific DNA aptamer was selected and confirmed through bioinformatics tools and docking software for binding to the surface of outer membrane protein U (OMP U) in V. cholerae. The aptamer sequence was synthesized, amplified, and used to coat the surface of GNPs. The effectiveness of the designed aptamer was evaluated for bacterial detection by observing the aggregation or non-aggregation of GNPs in the presence of NaCl. The colorimetric method and LSPR spectrum were used for final evaluation. The results of molecular docking indicated that the selected aptamer exhibited appropriate sensitivity and specificity in detecting the surface protein OMP U of the target bacteria in suspension. Additionally, the aptamer successfully detected bacteria with a detection limit of 10³ CFU/mL within 80 min. It displayed a significant optical shift of 8 nm compared to the absorption peak of GNPs, indicating successful detection of V. cholerae. The designed aptasensor demonstrated high sensitivity and specificity for V. cholerae and the potential for the development of rapid diagnostic kits to detect this bacterium.