Dark Field and Coherent Anti-Stokes Raman (DF-CARS) Imaging of Cell Uptake of Core-Shell, Magnetic-Plasmonic Nanoparticles
Magnetic-plasmonic, Fe<sub>3</sub>O<sub>4</sub>-Au, core-shell nanoparticles are popular in many applications, most notably in therapeutics and diagnostics, and thus, the imaging of these nanostructures in biological samples is of high importance. These nanostructures are typ...
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MDPI AG
2021-03-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/11/3/685 |
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| author | Grace Brennan Sally Ryan Tewfik Soulimane Syed A. M. Tofail Christophe Silien |
| author_facet | Grace Brennan Sally Ryan Tewfik Soulimane Syed A. M. Tofail Christophe Silien |
| author_sort | Grace Brennan |
| collection | DOAJ |
| description | Magnetic-plasmonic, Fe<sub>3</sub>O<sub>4</sub>-Au, core-shell nanoparticles are popular in many applications, most notably in therapeutics and diagnostics, and thus, the imaging of these nanostructures in biological samples is of high importance. These nanostructures are typically imaged in biological material by dark field scatter imaging, which requires an even distribution of nanostructures in the sample and, therefore, high nanoparticle doses, potentially leading to toxicology issues. Herein, we explore the nonlinear optical properties of magnetic nanoparticles coated with various thicknesses of gold using the open aperture z-scan technique to determine the nonlinear optical properties and moreover, predict the efficacy of the nanostructures in nonlinear imaging. We find that the magnetic nanoparticles coated with gold nanoseeds and thinner gold shells (ca. 4 nm) show the largest nonlinear absorption coefficient β and imaginary part of the third-order susceptibility Im χ<sup>(3)</sup>, suggesting that these nanostructures would be suitable contrast agents. Next, we combine laser dark field microscopy and epi-detected coherent anti-Stokes Raman (CARS) microscopy to image the uptake of magnetic-plasmonic nanoparticles in human pancreatic cancer cells. We show the epi-detected CARS technique is suitable for imaging of the magnetic-plasmonic nanoparticles without requiring a dense distribution of nanoparticles. This technique achieves superior nanoparticle contrasting over both epi-detected backscatter imaging and transmission dark field imaging, while also attaining label-free chemical contrasting of the cell. Lastly, we show the high biocompatibility of the Fe<sub>3</sub>O<sub>4</sub> nanoparticles with ca. 4-nm thick Au shell at concentrations of 10–100 µg/mL. |
| first_indexed | 2024-03-10T13:24:14Z |
| format | Article |
| id | doaj.art-7d5a5be92d374d359c01df2e79cd4855 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-10T13:24:14Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-7d5a5be92d374d359c01df2e79cd48552023-11-21T09:47:56ZengMDPI AGNanomaterials2079-49912021-03-0111368510.3390/nano11030685Dark Field and Coherent Anti-Stokes Raman (DF-CARS) Imaging of Cell Uptake of Core-Shell, Magnetic-Plasmonic NanoparticlesGrace Brennan0Sally Ryan1Tewfik Soulimane2Syed A. M. Tofail3Christophe Silien4Department of Physics and Bernal Institute, University of Limerick, V94 T9PX Limerick, IrelandDepartment of Chemical Sciences and Bernal Institute, University of Limerick, V94 T9PX Limerick, IrelandDepartment of Chemical Sciences and Bernal Institute, University of Limerick, V94 T9PX Limerick, IrelandDepartment of Physics and Bernal Institute, University of Limerick, V94 T9PX Limerick, IrelandDepartment of Physics and Bernal Institute, University of Limerick, V94 T9PX Limerick, IrelandMagnetic-plasmonic, Fe<sub>3</sub>O<sub>4</sub>-Au, core-shell nanoparticles are popular in many applications, most notably in therapeutics and diagnostics, and thus, the imaging of these nanostructures in biological samples is of high importance. These nanostructures are typically imaged in biological material by dark field scatter imaging, which requires an even distribution of nanostructures in the sample and, therefore, high nanoparticle doses, potentially leading to toxicology issues. Herein, we explore the nonlinear optical properties of magnetic nanoparticles coated with various thicknesses of gold using the open aperture z-scan technique to determine the nonlinear optical properties and moreover, predict the efficacy of the nanostructures in nonlinear imaging. We find that the magnetic nanoparticles coated with gold nanoseeds and thinner gold shells (ca. 4 nm) show the largest nonlinear absorption coefficient β and imaginary part of the third-order susceptibility Im χ<sup>(3)</sup>, suggesting that these nanostructures would be suitable contrast agents. Next, we combine laser dark field microscopy and epi-detected coherent anti-Stokes Raman (CARS) microscopy to image the uptake of magnetic-plasmonic nanoparticles in human pancreatic cancer cells. We show the epi-detected CARS technique is suitable for imaging of the magnetic-plasmonic nanoparticles without requiring a dense distribution of nanoparticles. This technique achieves superior nanoparticle contrasting over both epi-detected backscatter imaging and transmission dark field imaging, while also attaining label-free chemical contrasting of the cell. Lastly, we show the high biocompatibility of the Fe<sub>3</sub>O<sub>4</sub> nanoparticles with ca. 4-nm thick Au shell at concentrations of 10–100 µg/mL.https://www.mdpi.com/2079-4991/11/3/685magnetic-plasmonic nanoparticlescoherent anti-Stokes Raman (CARS)cell imagingnonlinear opticscontrast agentsz-scan |
| spellingShingle | Grace Brennan Sally Ryan Tewfik Soulimane Syed A. M. Tofail Christophe Silien Dark Field and Coherent Anti-Stokes Raman (DF-CARS) Imaging of Cell Uptake of Core-Shell, Magnetic-Plasmonic Nanoparticles Nanomaterials magnetic-plasmonic nanoparticles coherent anti-Stokes Raman (CARS) cell imaging nonlinear optics contrast agents z-scan |
| title | Dark Field and Coherent Anti-Stokes Raman (DF-CARS) Imaging of Cell Uptake of Core-Shell, Magnetic-Plasmonic Nanoparticles |
| title_full | Dark Field and Coherent Anti-Stokes Raman (DF-CARS) Imaging of Cell Uptake of Core-Shell, Magnetic-Plasmonic Nanoparticles |
| title_fullStr | Dark Field and Coherent Anti-Stokes Raman (DF-CARS) Imaging of Cell Uptake of Core-Shell, Magnetic-Plasmonic Nanoparticles |
| title_full_unstemmed | Dark Field and Coherent Anti-Stokes Raman (DF-CARS) Imaging of Cell Uptake of Core-Shell, Magnetic-Plasmonic Nanoparticles |
| title_short | Dark Field and Coherent Anti-Stokes Raman (DF-CARS) Imaging of Cell Uptake of Core-Shell, Magnetic-Plasmonic Nanoparticles |
| title_sort | dark field and coherent anti stokes raman df cars imaging of cell uptake of core shell magnetic plasmonic nanoparticles |
| topic | magnetic-plasmonic nanoparticles coherent anti-Stokes Raman (CARS) cell imaging nonlinear optics contrast agents z-scan |
| url | https://www.mdpi.com/2079-4991/11/3/685 |
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