Antibody-Conjugated Rubpy Dye-Doped Silica Nanoparticles as Signal Amplification for Microscopic Detection of Vibrio cholerae O1

This study demonstrated the potential application of antibody-conjugated Rubpy dye-doped silica nanoparticles for immunofluorescence microscopic detection of Vibrio cholerae O1. The particle synthesis of 20X of the original ratio was accomplished yielding spherical nanoparticles with an average size of 45 +/- 3 nm. The nanoparticles were carboxyl functionalized and then conjugated with either monoclonal antibody or polyclonal antibody against V. cholerae O1. The antibody-conjugated nanoparticles were tested with two target bacteria and three challenge strains. The result showed that monoclonal antibody-conjugated Rubpy dye-doped silica nanoparticles could be effectively used as signal amplification to detect V. cholerae O1 under a fluorescence microscope. Their extremely strong fluorescence signal also enables the detection of a single cell bacterium.