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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 a dual recognition mechanism for surface enhanced Raman spectroscopic (SERS) pathogen detection; the superimposed bacterial signature peaks and probe signatures peaks indicate the binding between the bacterial target and the nanoprobes.
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biosensors-03-00312-f001: Schematic illustration of a dual recognition mechanism for surface enhanced Raman spectroscopic (SERS) pathogen detection; the superimposed bacterial signature peaks and probe signatures peaks indicate the binding between the bacterial target and the nanoprobes.

Mentions: In this study we introduced a concept of self-referencing mechanism that utilizes SERS molecular probes to achieve bacteria detection in one single step in a test-in-a-tube platform, which would be more suitable for in-field applications. As shown in Figure 1, in the dual-recognition mechanism, Raman-labeled and antibody-functionalized anisotropic nanostructures (e.g., silver nanocubes) are fabricated as SERS nanoprobes that display specific probe signatures (probe signal), and through covalently-bound antibodies they could bind to their target bacterial cells specifically. The selection of silver nanocube as the SERS probe is to take advantage of the superior electromagnetic enhancement of anisotropic nanoparticle to Raman scattering of target molecules in their vicinity, due to the geometrical singularity of these nanoparticles [21,22,23,24]. The antibody-antigen binding ensures that the target cells would bind to enough nanoprobes, and measureable SERS signals from the bacterial cells would be generated (non-target would NOT have enough nanoprobes bound to them, and their SERS signal would be non-measurable due to weak or no enhancement). Observation of superimposed SERS signals of the probe and the target indicates the binding events, and subsequently definitely identifies the target in one single step; no washing or separation is needed. Furthermore, since the specificity of the target detection is provided by the antibodies, only a few key signature peaks from the bacterial cells are needed for the target recognition, a positive identification of the target can be reached without relying on multivariate analysis throughout a broad spectral range. A portable Raman sensor thus becomes feasible under the self-referencing dual-recognition scheme for target detection, as shown in this study.


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 a dual recognition mechanism for surface enhanced Raman spectroscopic (SERS) pathogen detection; the superimposed bacterial signature peaks and probe signatures peaks indicate the binding between the bacterial target and the nanoprobes.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-03-00312-f001: Schematic illustration of a dual recognition mechanism for surface enhanced Raman spectroscopic (SERS) pathogen detection; the superimposed bacterial signature peaks and probe signatures peaks indicate the binding between the bacterial target and the nanoprobes.
Mentions: In this study we introduced a concept of self-referencing mechanism that utilizes SERS molecular probes to achieve bacteria detection in one single step in a test-in-a-tube platform, which would be more suitable for in-field applications. As shown in Figure 1, in the dual-recognition mechanism, Raman-labeled and antibody-functionalized anisotropic nanostructures (e.g., silver nanocubes) are fabricated as SERS nanoprobes that display specific probe signatures (probe signal), and through covalently-bound antibodies they could bind to their target bacterial cells specifically. The selection of silver nanocube as the SERS probe is to take advantage of the superior electromagnetic enhancement of anisotropic nanoparticle to Raman scattering of target molecules in their vicinity, due to the geometrical singularity of these nanoparticles [21,22,23,24]. The antibody-antigen binding ensures that the target cells would bind to enough nanoprobes, and measureable SERS signals from the bacterial cells would be generated (non-target would NOT have enough nanoprobes bound to them, and their SERS signal would be non-measurable due to weak or no enhancement). Observation of superimposed SERS signals of the probe and the target indicates the binding events, and subsequently definitely identifies the target in one single step; no washing or separation is needed. Furthermore, since the specificity of the target detection is provided by the antibodies, only a few key signature peaks from the bacterial cells are needed for the target recognition, a positive identification of the target can be reached without relying on multivariate analysis throughout a broad spectral range. A portable Raman sensor thus becomes feasible under the self-referencing dual-recognition scheme for target detection, as shown in this study.

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