On the importance of optical forces in surface-enhanced Raman scattering (SERS)

Svedberg, Fredrik; Käll, Mikael

doi:10.1039/b509301p

Cited by 43 publications

(28 citation statements)

References 42 publications

(59 reference statements)

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“…The system is equipped with an excitation source at 532 nm, provided by a frequency doubled Nd:YAG. The silver colloids that formed the SERS-active substrate were prepared according to the standard procedure of Lee and Meisel [30], which is known to produce spherical Ag nanoparticles with an average diameter of 40 nm [31]. Briefly, AgNO 3 (90 mg) was dissolved in 500 mL of H 2 O and brought to boil.…”

Section: Methodsmentioning

confidence: 99%

Flexibility of the Prograamme of Spore Coat Formation in Bacillus subtilis: Bypass of CotE Requirement by Over-Production of CotH

et al. 2013

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Bacterial spores are surrounded by the coat, a multilayered shell that contributes in protecting the genome during stress conditions. In Bacillus subtilis, the model organism for spore formers, the coat is composed by about seventy different proteins, organized into four layers by the action of several regulatory proteins. A major component of this regulatory network, CotE, is needed to assemble the outer coat and develop spores fully resistant to lysozyme and able to germinate efficiently. Another regulator, CotH, is controlled by CotE and is present in low amounts both during sporulation and in mature spores. In spite of this CotH controls the assembly of at least nine outer coat proteins and cooperates with CotE in producing fully resistant and efficiently germinating spores. In order to improve our understanding of CotH role in spore formation, we over-produced CotH by placing its coding region under the control of a promoter stronger than its own promoter but with a similar timing of activity during sporulation. Over-production of CotH in an otherwise wild type strain did not cause any major effect, whereas in a cotE null background a partial recovery of the phenotypes associated to the cotE null mutation was observed. Western blot, fluorescence microscopy and Surface-Enhanced Raman Scattering spectroscopy data indicate that, in the absence of CotE, over-production of CotH allowed the formation of spores overall resembling wild type spores and carrying in their coat some CotE−/CotH-dependant proteins. Our results suggest that the B. subtilis spore differentiation programme is flexible, and that an increase in the amount of a regulatory protein can replace a missing partner and partially substitute its function in the assembly of the spore coat.

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Section: Methodsmentioning

confidence: 99%

Flexibility of the Prograamme of Spore Coat Formation in Bacillus subtilis: Bypass of CotE Requirement by Over-Production of CotH

et al. 2013

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“…126 However, larger particles exhibited reduced heating, probably because the radiation pressure forced these particles away from the laser focus. It should be pointed out that neither of these studies [103][104] , nor the previously mentioned studies of particle rotation 89 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 …”

Section: Heating Of Optically Trapped Metal Colloidsmentioning

confidence: 91%

Laser Trapping of Colloidal Metal Nanoparticles

et al. 2015

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Optical trapping using focused laser beams (laser tweezers) has been proven to be extremely useful for contactless manipulation of a variety of small objects, including biological cells, organelles within cells, and a wide range of other dielectric micro- and nano-objects. Colloidal metal nanoparticles have drawn increasing attention in the field of optical trapping because of their unique interactions with electromagnetic radiation, caused by surface plasmon resonance effects, enabling a large number of nano-optical applications of high current interest. Here we try to give a comprehensive overview of the field of laser trapping and manipulation of metal nanoparticles based on results reported in the recent literature. We also discuss and describe the fundamentals of optical forces in the context of plasmonic nanoparticles, including effects of polarization, optical angular momentum, and laser heating effects, as well as the various techniques that have been used to trap and manipulate metal nanoparticles. We conclude by suggesting possible directions for future research.

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“…Laser forces on the probe molecule could be an option but it has not yet been demonstrated experimentally to occur. 10 The probe molecule(s) therefore adsorb at a random position on the substrate. The most common approach currently relies on an ultra-low concentration of analyte, which ensures that one molecule (at most) will adsorb at the HS and in principle guarantees the single molecule nature of the dectected signals.…”

Section: 2mentioning

confidence: 99%

Enhancement factor distribution around a single surface-enhanced Raman scattering hot spot and its relation to single molecule detection

Etchegoin

Meyer

2006

The Journal of Chemical Physics

357

295

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We provide the theoretical framework to understand the phenomenology and statistics of singlemolecule (SM) signals arising in Surface-Enhanced Raman Scattering (SERS) under the presence of so-called electromagnetic hot-spots (HS's). We show that most characteristics of the SM-SERS phenomenon can be tracked down to the presence of tail-like (power law) distribution of enhancements and we propose a specific model for it. We analyze, in the light of this, the phenomenology of SM-SERS and show how the different experimental manifestations of the effect reported in the literature can be analyzed and understood under a unified "universal" framework with a minimum set of parameters.

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On the importance of optical forces in surface-enhanced Raman scattering (SERS)

Cited by 43 publications

References 42 publications

Flexibility of the Prograamme of Spore Coat Formation in Bacillus subtilis: Bypass of CotE Requirement by Over-Production of CotH

Flexibility of the Prograamme of Spore Coat Formation in Bacillus subtilis: Bypass of CotE Requirement by Over-Production of CotH

Laser Trapping of Colloidal Metal Nanoparticles

Enhancement factor distribution around a single surface-enhanced Raman scattering hot spot and its relation to single molecule detection

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