Silica coated Magnetic Nanoparticles (SMNPs): Capture and Identification of Escherichia coli Cells using Surface Enhanced Raman Spectroscopy

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Silica coated Magnetic nanoparticles (SMNPs; SiO2/Fe3O4 + Fe2O3) were prepared by encapsulation of iron oxide NPs with silica dioxide using the sol-gel method and characterized through transmission and scanning electron microscopic imaging, magnetic hysteresis and Fourier transform infrared spectroscopy. The hydroxyl group of SMNPs surface were chemically activated with cyanogens bromide and then functionalized with specific polyclonal antibodies. The functionalized NPs were used to capture and concentrate the environmental Escherichia coli (E. coli) from several local environmentally impacted water streams. Captured bacteria were identified using UV-visible spectroscopy, plating on nutrient agar and fluorescent microscopic imaging. Raman spectroscopy was used for detection and monitoring of bacterial disintegration in presence of silver nitrate solution. Raman spectra of bacterial complex shows the various characteristics biomolecules, this confirms the detection of E. coli captured by SMNPs. This method may ultimately be use as a rapid monitoring procedure for water quality.

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Journal: TechConnect Briefs
Volume: 3, Nanotechnology 2011: Bio Sensors, Instruments, Medical, Environment and Energy
Published: June 13, 2011
Pages: 68 - 71
Industry sectors: Medical & Biotech | Sensors, MEMS, Electronics
Topics: Chemical, Physical & Bio-Sensors, Diagnostics & Bioimaging
ISBN: 978-1-4398-7138-6