Monitoring DPA Release from a Single Germinating <i>Bacillus s</i><i>ubtilis</i> Endospore via Surface-Enhanced Raman Scattering Microscopy

Evanoff, David D.; Heckel, John; Caldwell, Thomas P.; Christensen, Kenneth A.; Chumanov, George

doi:10.1021/ja0642717

Cited by 46 publications

(40 citation statements)

References 18 publications

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“…The calculations assumed 10% collection and detection efficiency for the instrumentation and the optical cross section of a single Ag NP to be 5 times the geometric cross section. 33 The normal Raman scattering cross section of adenine (10 -30 cm 2 /molecule) was taken from ref 18. The absolute intensities of the SERS signals scaled as 3 × 10 3 cps for adenine, 1.7 × 10 4 cps for 4-ATP, Resonance Elastic Scattering.…”

Section: Resultsmentioning

confidence: 99%

Surface Enhanced Raman Scattering and Resonance Elastic Scattering from Capped Single Ag Nanoparticles

Hudson¹,

Chumanov²

2008

J. Phys. Chem. C

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Capped Ag nanoparticles with the novel silver core-molecule-silver cap structure were synthesized and demonstrated to produce strong SERS. Plasmon-induced electronic coupling was concluded to be the major Raman enhancement mechanism. The capped nanoparticles also exhibited polarization-dependent elastic light scattering that was attributed to the particle anisotropy, which resulted from the addition of the silver cap. These particles can potentially be used as optical labels.

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Section: Resultsmentioning

confidence: 99%

Surface Enhanced Raman Scattering and Resonance Elastic Scattering from Capped Single Ag Nanoparticles

Hudson¹,

Chumanov²

2008

J. Phys. Chem. C

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“…Among these techniques, SERS is of particular interest because of its sensitivity, discrimination, and quick detection. [32,33] However, reduction of the limit of detection (LOD) of these molecules to a desirable value has been a challenge for SERS-based detection methods. [34] In this case, we explored the possibility of directly detecting a low concentration of CaDPA molecules by using the optimized silver-coated silicon nanowire arrays as SERS substrates.…”

Section: Full Papermentioning

confidence: 99%

Large‐Area Silver‐Coated Silicon Nanowire Arrays for Molecular Sensing Using Surface‐Enhanced Raman Spectroscopy

Zhang

Wang

et al. 2008

Adv Funct Materials

360

220

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A new and facile method to prepare large‐area silver‐coated silicon nanowire arrays for surface‐enhanced Raman spectroscopy (SERS)‐based sensing is introduced. High‐quality silicon nanowire arrays are prepared by a chemical etching method and used as a template for the generation of SERS‐active silver‐coated silicon nanowire arrays. The morphologies of the silicon nanowire arrays and the type of silver‐plating solution are two key factors determining the magnitude of SERS signal enhancement and the sensitivity of detection; they are investigated in detail for the purpose of optimization. The optimized silver‐coated silicon nanowire arrays exhibit great potential for ultrasensitive molecular sensing in terms of high SERS signal enhancement ability, good stability, and reproducibility. Their further applications in rapidly detecting molecules relating to human health and safety are discussed. A 10 s data acquisition time is capable of achieving a limit of detection of approximately 4 × 10−6 M calcium dipicolinate (CaDPA), a biomarker for anthrax. This value is 1/15 the infectious dose of spores (6 × 10−5 M required), revealing that the optimized silver‐coated silicon nanowire arrays as SERS‐based ultrasensitive sensors are extremely suitable for detecting Bacillus anthracis spores.

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“…However, the full decrease in the core’s refractive index is due to CaDPA release as well as to full core rehydration (13). The kinetics of CaDPA release during germination of single spores has also been followed by Raman (19) and surface enhanced Raman spectroscopy (24). In particular, laser tweezers Raman spectroscopy (LTRS) has demonstrated significant heterogeneity in the kinetics of CaDPA release during germination of individual spores (19).…”

Section: Introductionmentioning

confidence: 99%

Elastic and Inelastic Light Scattering from Single Bacterial Spores in an Optical Trap Allows the Monitoring of Spore Germination Dynamics

et al. 2009

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Raman scattering spectroscopy and elastic light scattering intensity (ESLI) were used to simultaneously measure levels of Ca-dipicolinic acid (CaDPA) and changes in spore morphology and refractive index during germination of individual B. subtilis spores with and without the two redundant enzymes (CLEs), CwlJ and SleB, that degrade spores' peptidoglycan cortex. Conclusions from these measurements include: 1) CaDPA release from individual wild-type germinating spores was biphasic; in a first heterogeneous slow phase, T lag , CaDPA levels decreased ∼15% and in the second phase ending at T release , remaining CaDPA was released rapidly; 2) in L-alanine germination of wild-type spores and spores lacking SleB: a) the ESLI rose ∼2-fold shortly before T lag at T 1 ; b) following T lag , the ESLI again rose ∼2-fold at T 2 when CaDPA levels had decreased ∼50%; and c) the ESLI reached its maximum value at ∼T release and then decreased; 3) in CaDPA germination of wild-type spores: a) T lag increased and the first increase in ESLI occurred well before T lag , consistent with different pathways for CaDPA and L-alanine germination; b) at T release the ESLI again reached its maximum value; 4) in L-alanine germination of spores lacking both CLEs and unable to degrade their cortex, the time ΔT release (T release -T lag ) for excretion of ≥75% of CaDPA was ∼15-fold higher than that for wild-type or sleB spores; and 5) spores lacking only CwlJ exhibited a similar, but not identical ESLI pattern during L-alanine germination to that seen with cwlJ sleB spores, and the high value for ΔT release .

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Monitoring DPA Release from a Single Germinating Bacillus subtilis Endospore via Surface-Enhanced Raman Scattering Microscopy

Cited by 46 publications

References 18 publications

Surface Enhanced Raman Scattering and Resonance Elastic Scattering from Capped Single Ag Nanoparticles

Surface Enhanced Raman Scattering and Resonance Elastic Scattering from Capped Single Ag Nanoparticles

Large‐Area Silver‐Coated Silicon Nanowire Arrays for Molecular Sensing Using Surface‐Enhanced Raman Spectroscopy

Elastic and Inelastic Light Scattering from Single Bacterial Spores in an Optical Trap Allows the Monitoring of Spore Germination Dynamics

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