Antibody-Conjugated Rubpy Dye-Doped Silica Nanoparticles as Signal Amplification for Microscopic Detection ofVibrio choleraeO1

Nualrahong Thepwiwatjit,Pichet Limsuwan,Pravate Tuitemwong,Aree Thattiyaphong,Kooranee Tuitemwong

doi:10.1155/2013/274805

Abstract

This study demonstrated the potential application of antibody-conjugated Rubpy dye-doped silica nanoparticles for immunofluorescence microscopic detection ofVibrio choleraeO1. The particle synthesis of 20X of the original ratio was accomplished yielding spherical nanoparticles with an average size of45±3 nm. The nanoparticles were carboxyl functionalized and then conjugated with either monoclonal antibody or polyclonal antibody againstV. choleraeO1. 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 detectV. choleraeO1 under a fluorescence microscope. Their extremely strong fluorescence signal also enables the detection of a single cell bacterium.

Highlights

The standard or conventional methods for microbial detection are the cultural methods which primarily rely on the preenrichment and specific enrichment steps to enumerate the organisms that may occur in low numbers in the sample, followed by the isolation of the bacteria in solid media and a final confirmation by biochemical identification and/or serological tests
Polyclonal rabbit anti-V. cholerae O1 antibody and monoclonal antibody specific to Vibrio cholerae O1 were obtained from the National Institute of Health, Department of Medical Science, Thailand
The Rubpy dye which previously dissolved in water was encapsulated inside a silica network and formed fluorescent dye-doped silica nanoparticles (FDSNPs)

Summary

Introduction

The standard or conventional methods for microbial detection are the cultural methods which primarily rely on the preenrichment and specific enrichment steps to enumerate the organisms that may occur in low numbers in the sample, followed by the isolation of the bacteria in solid media and a final confirmation by biochemical identification and/or serological tests. These methods are considered time consuming and labor intensive. Rapid methods to identify the pathogens with high accurately and sensitivity are very crucial. Rapid microbiology methods have long been practiced including PCR [2,3,4], ELISA [5, 6], immunosensor [7], biosensors [8, 9], and immunochromatographic test strips [10,11,12]

Methods

Results

Conclusion