Manipulation and Raman Spectroscopy with Optically Trapped Metal Nanoparticles Obtained by Pulsed Laser Ablation in Liquids

Messina, Elena; Cavallaro, E.; Cacciola, Adriano; Saija, Rosalba; Borghese, Ferdinando; Denti, P.; Fazio, Barbara; D’Andrea, Cristiano; Gucciardi, P. G.; Iatí, Maria Antonia; Meneghetti, Moreno; Compagnini, Giuseppe; Amendola, Vincenzo; Maragó, Onofrio M.

doi:10.1021/jp109405j

Cited by 68 publications

(51 citation statements)

References 58 publications

(127 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, Au‐Fe alloy aggregates show plasmon absorption in the red and near‐infrared region of electromagnetic spectrum (red line in Figure f), thus endowing photothermal effects . As confirmed by DDA calculations, the red and near‐infrared absorption is due to particle aggregation (black line in Figure f).…”

Section: Resultsmentioning

confidence: 63%

Magneto‐Plasmonic Au‐Fe Alloy Nanoparticles Designed for Multimodal SERS‐MRI‐CT Imaging

Amendola

Scaramuzza

Litti

et al. 2014

Small

172

174

View full text Add to dashboard Cite

Diagnostic approaches based on multimodal imaging are needed for accurate selection of the therapeutic regimens in several diseases, although the dose of administered contrast drugs must be reduced to minimize side effects. Therefore, large efforts are deployed in the development of multimodal contrast agents (MCAs) that permit the complementary visualization of the same diseased area with different sensitivity and different spatial resolution by applying multiple diagnostic techniques. Ideally, MCAs should also allow imaging of diseased tissues with high spatial resolution during surgical interventions. Here a new system based on multifunctional Au-Fe alloy nanoparticles designed to satisfy the main requirements of an ideal MCA is reported and their biocompatibility and imaging capability are described. The MCAs show easy and versatile surface conjugation with thiolated molecules, magnetic resonance imaging (MRI) and computed X-ray tomography (CT) signals for anatomical and physiological information (i.e., diagnostic and prognostic imaging), large Raman signals amplified by surface enhanced Raman scattering (SERS) for high sensitivity and high resolution intrasurgical imaging, biocompatibility, exploitability for in vivo use and capability of selective accumulation in tumors by enhanced permeability and retention effect. Taken together, these results show that Au-Fe nanoalloys are excellent candidates as multimodal MRI-CT-SERS imaging agents.

show abstract

Section: Resultsmentioning

confidence: 63%

Magneto‐Plasmonic Au‐Fe Alloy Nanoparticles Designed for Multimodal SERS‐MRI‐CT Imaging

Amendola

Scaramuzza

Litti

et al. 2014

Small

172

174

View full text Add to dashboard Cite

show abstract

“…PlEnS enable the development of high sensitivity, multiband spectroscopic nanosensors for label-free detection of chemical and biomolecular compounds [11][12][13][14][15][16][17]. the polarized signal is always maximum in the direction parallel to the excitation field.…”

Section: Introductionmentioning

confidence: 99%

On the SERS depolarization ratio

et al. 2015

View full text Add to dashboard Cite

According to the E 4 model, [18][19][20][21][22][23][24] in SERS the nanoantenna plays a twofold role: firstly it amplifies the local field (excitation-field enhancement) confining it to nanoscale regions (hot spots), and secondly it magnifies the Raman scattering (re-radiation enhancement). Molecules lying in the hot spots (located at the edges of individual nanoantennas or in the nanocavities between near-field coupled NPs [15,[25][26][27][28][29]) experience an amplified local field and an enhanced re-radiation whenever both the wavelengths of the laser pump (λ L ) and of the induced Raman dipole (λ R ) are close to the LSPR wavelength (λ LSPR ) [24]. It is well known that the enhanced local field is polarization sensitive. The only component of the incident field yielding the local field amplification is the one capable of exciting the LSPR of the antenna [30][31][32][33]. On the other hand, in near-field coupled nanoantennas the re-radiation effect yields a selective enhancement of the Raman dipole component parallel to the nanocavity axis at the single molecule level, linearizing the polarization of the Raman field [34][35][36][37][38].The re-radiation effect, therefore, causes a strong modification of the polarization of the SERS field, whose components will be altered with respect to what would have been measured in normal Raman spectroscopy in absence of the nanoantennas. In addition, such an alteration is dependent on the orientation of the antenna.A measurable quantity that will be strongly affected from such dependence is the depolarization ratio [39]. It is defined in Raman spectroscopy (for linear excitation polarization) as the ratio between the intensity of the Raman field polarized orthogonal to the laser field (I ⟘ ) and the intensity of the Raman field polarized parallel to the laser field (I � ). The depolarization ratio provides information on the Raman polarizability tensor (α) of the vibration considered and is therefore a very useful tool.It was recognized early on that in SERS the relationship between the depolarization ratio and the components of the Raman polarizability tensor was not straightforward [3]. One striking example is provided by Fazio and coworkers, [38] where the polarized SERS intensity is found to be at a maximum in the direction orthogonal to the excitation field, whereas in Raman spectroscopy Abstract: The Raman depolarization ratio is a quantity that can be easily measured experimentally and offers unique information on the Raman polarizability tensor of molecular vibrations. In Surface Enhanced Raman Scattering (SERS), molecules are near-field coupled with optical nanoantennas and their scattering properties are strongly affected by the radiation patterns of the nanoantenna. The polarization of the SERS photons is consequently modified, affecting, in a non trivial way, the measured value of the SERS depolarization ratio. In this article we elaborate a model that describes how the SERS depolarization ratio is influenced by the nanoantenna re-radiation properties, sugg...

show abstract

“…One dimensional ceramic nanostructures have been synthesized by various processes, including, hydrothermal [1,5,6], laser ablation [7,8], chemical vapor deposition (CVD) [9-11] and electro-spinning [12-14]. The shared disadvantages of current fabrication methods for one dimensional nanomaterials include, complex processing parameters (e.g.…”

Section: Introductionmentioning

confidence: 99%

Centrifugal jet spinning for highly efficient and large-scale fabrication of barium titanate nanofibers

Ren

Kotha

2014

Materials Letters

View full text Add to dashboard Cite

The centrifugal jet spinning (CJS) method has been developed to enable large-scale synthesis of barium titanate nanofibers. Barium titanate nanofibers with fiber diameters down to 50 nm and grain sizes around 25 nm were prepared with CJS by spinning a sol-gel solution of barium titanate and poly(vinylpyrrolidone) with subsequent heat treatment at 850 °C. XRD and FTIR analysis demonstrated high purity and tetragonal perovskite structured barium titanate nanofibers. SEM and TEM images confirm the continuous high aspect ratio structure of barium titanate nanofibers after heat treatment. It is demonstrated that the CJS technique offers a highly efficient method for large-scale fabrication of ceramic nanofibers at production rates of up to 0.3 gram/minute.

show abstract

Manipulation and Raman Spectroscopy with Optically Trapped Metal Nanoparticles Obtained by Pulsed Laser Ablation in Liquids

Cited by 68 publications

References 58 publications

Magneto‐Plasmonic Au‐Fe Alloy Nanoparticles Designed for Multimodal SERS‐MRI‐CT Imaging

Magneto‐Plasmonic Au‐Fe Alloy Nanoparticles Designed for Multimodal SERS‐MRI‐CT Imaging

On the SERS depolarization ratio

Centrifugal jet spinning for highly efficient and large-scale fabrication of barium titanate nanofibers

Contact Info

Product

Resources

About