SERS-based sandwich immunoassay using antibody coated magnetic nanoparticles for Escherichia coli enumeration
- 1 December 2010
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in The Analyst
- Vol. 136 (4), 740-748
- https://doi.org/10.1039/c0an00473a
Abstract
A method combining immunomagnetic separation (IMS) and surface-enhanced Raman scattering (SERS) was developed to enumerate Escherichia coli (E. coli). Gold-coated magnetic spherical nanoparticles were prepared by immobilizing biotin-labeled anti-E. coliantibodies onto avidin-coated magnetic nanoparticles and used in the separation and concentration of the E. colicells. Raman labels have been constructed using rod shaped gold nanoparticles coated with 5,5-dithiobis-(2-nitrobenzoic acid) (DTNB) and subsequently with a molecular recognizer. Then DTNB-labeled gold nanorods were interacted with gold-coated magnetic spherical nanoparticle-antibody-E. coli complex. The capture efficiency and calibration graphs were obtained and examined in different E. coli concentrations (101–107 cfu mL−1). The correlation between the concentration of bacteria and SERS signal was found to be linear within the range of 101–104 cfu mL−1 (R2 = 0.992). The limit of detection (LOD) and limit of quantification (LOQ) values of the developed method were found to be 8 and 24 cfu mL−1, respectively. The selectivity of the developed immunoassay was examined with Enterobacter aerogenes, Enterobacter dissolvens, and Salmonella enteriditis which did not produce any significant response. The ability of the immunoassay to detect E. coli in real water samples was also investigated and the results were compared with the experimental results from plate-counting methods. There was no significant difference between the methods that were compared (p > 0.05). This method is rapid and sensitive to target organisms with a total analysis time of less than 70 min.This publication has 54 references indexed in Scilit:
- Combining biofunctional magnetic nanoparticles and ATP bioluminescence for rapid detection of Escherichia coliTalanta, 2008
- Molecular beacons: A real-time polymerase chain reaction assay for detecting Escherichia coli from fresh produce and waterAnalytica Chimica Acta, 2008
- A conductometric immunosensor based on functionalized magnetite nanoparticles for E. coli detectionElectrochemistry Communications, 2008
- Nanotechnology in the Detection and Control of MicroorganismsAdvances in Applied Microbiology, 2008
- Direct detection of E. Coli O157:H7 in selected food systems by a surface plasmon resonance biosensorLWT, 2007
- Nonlabeled Quartz Crystal Microbalance Biosensor for Bacterial Detection Using Carbohydrate and Lectin RecognitionsAnalytical Chemistry, 2007
- Magnetic Nanoparticle-Antibody Conjugates for the Separation of Escherichia coli O157:H7 in Ground BeefJournal of Food Protection, 2005
- Magnetite-Containing Spherical Silica Nanoparticles for Biocatalysis and BioseparationsAnalytical Chemistry, 2004
- Application of a flow-type antibody sensor to the detection of Escherichia coli in various foodsBiosensors and Bioelectronics, 2003
- PCR-ELISA detection of Escherichia coli in milkLetters in Applied Microbiology, 2002