Limits...
A Self-Referencing Detection of Microorganisms Using Surface Enhanced Raman Scattering Nanoprobes in a Test-in-a-Tube Platform.

Xiao N, Wang C, Yu C - Biosensors (Basel) (2013)

Bottom Line: Anisotropic nanoparticles (i.e., silver nanocubes) were functionalized with target-specific antibodies and Raman active tags to serve as nanoprobes for the rapid detection of bacteria in a test-in-a-tube platform.The assessment through the dual signals (superimposed target and tag Raman signatures) supported a specific recognition of the targets in a single step with no washing/separation needed to a sensitivity of 102 CFU/mL, even in the presence of non-target bacteria at a 10 times higher concentration.The self-referencing protocol implemented with a portable Raman spectrometer potentially can become an easy-to-use, field-deployable spectroscopic sensor for onsite detection of pathogenic microorganisms.

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA 50011, USA. nxiao@iastate.edu.

ABSTRACT
Anisotropic nanoparticles (i.e., silver nanocubes) were functionalized with target-specific antibodies and Raman active tags to serve as nanoprobes for the rapid detection of bacteria in a test-in-a-tube platform. A self-referencing scheme was developed and implemented in which surface enhanced Raman spectroscopic (SERS) signatures of the targets were observed superimposed with the SERS signals of the Raman tags. The assessment through the dual signals (superimposed target and tag Raman signatures) supported a specific recognition of the targets in a single step with no washing/separation needed to a sensitivity of 102 CFU/mL, even in the presence of non-target bacteria at a 10 times higher concentration. The self-referencing protocol implemented with a portable Raman spectrometer potentially can become an easy-to-use, field-deployable spectroscopic sensor for onsite detection of pathogenic microorganisms.

No MeSH data available.


Related in: MedlinePlus

Schematic illustration of the experimental setup.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4263577&req=5

biosensors-03-00312-f003: Schematic illustration of the experimental setup.

Mentions: To acquire SERS spectra of the bacteria-nanoprobe sample, 10 µL of the sample was withdrawn from the eppendorf tube and put into a cap of an eppendorf tube (removed from a tube). The cap was used as a sampling container. It was put at the focal point (6 cm measuring from the tip of the i-Raman spectrometer (B&W Tek, Inc., Newark, DE, USA) as shown in Figure 3) of the i-Raman laser beam (15 mW, 785 nm NIR laser, 3 cm−1 spectral resolution, 400–2,000 cm−1 range). The focal point of the laser beam was pre-set by the manufacturer. Raman spectra of the sample were hence obtained directly with no washing being performed after the mixing of the bacterial suspension and the nanoprobes in one single step. 60 s integration time was used at 15 mW laser power for spectral acquisition. 10 spectra were collected from each sample to calculate an average spectrum, which was used for further analysis.


A Self-Referencing Detection of Microorganisms Using Surface Enhanced Raman Scattering Nanoprobes in a Test-in-a-Tube Platform.

Xiao N, Wang C, Yu C - Biosensors (Basel) (2013)

Schematic illustration of the experimental setup.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263577&req=5

biosensors-03-00312-f003: Schematic illustration of the experimental setup.
Mentions: To acquire SERS spectra of the bacteria-nanoprobe sample, 10 µL of the sample was withdrawn from the eppendorf tube and put into a cap of an eppendorf tube (removed from a tube). The cap was used as a sampling container. It was put at the focal point (6 cm measuring from the tip of the i-Raman spectrometer (B&W Tek, Inc., Newark, DE, USA) as shown in Figure 3) of the i-Raman laser beam (15 mW, 785 nm NIR laser, 3 cm−1 spectral resolution, 400–2,000 cm−1 range). The focal point of the laser beam was pre-set by the manufacturer. Raman spectra of the sample were hence obtained directly with no washing being performed after the mixing of the bacterial suspension and the nanoprobes in one single step. 60 s integration time was used at 15 mW laser power for spectral acquisition. 10 spectra were collected from each sample to calculate an average spectrum, which was used for further analysis.

Bottom Line: Anisotropic nanoparticles (i.e., silver nanocubes) were functionalized with target-specific antibodies and Raman active tags to serve as nanoprobes for the rapid detection of bacteria in a test-in-a-tube platform.The assessment through the dual signals (superimposed target and tag Raman signatures) supported a specific recognition of the targets in a single step with no washing/separation needed to a sensitivity of 102 CFU/mL, even in the presence of non-target bacteria at a 10 times higher concentration.The self-referencing protocol implemented with a portable Raman spectrometer potentially can become an easy-to-use, field-deployable spectroscopic sensor for onsite detection of pathogenic microorganisms.

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA 50011, USA. nxiao@iastate.edu.

ABSTRACT
Anisotropic nanoparticles (i.e., silver nanocubes) were functionalized with target-specific antibodies and Raman active tags to serve as nanoprobes for the rapid detection of bacteria in a test-in-a-tube platform. A self-referencing scheme was developed and implemented in which surface enhanced Raman spectroscopic (SERS) signatures of the targets were observed superimposed with the SERS signals of the Raman tags. The assessment through the dual signals (superimposed target and tag Raman signatures) supported a specific recognition of the targets in a single step with no washing/separation needed to a sensitivity of 102 CFU/mL, even in the presence of non-target bacteria at a 10 times higher concentration. The self-referencing protocol implemented with a portable Raman spectrometer potentially can become an easy-to-use, field-deployable spectroscopic sensor for onsite detection of pathogenic microorganisms.

No MeSH data available.


Related in: MedlinePlus