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Multimodal near-infrared-emitting PluS Silica nanoparticles with fluorescent, photoacoustic, and photothermal capabilities

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: The aim of the present study was to develop nanoprobes with theranostic features, including – at the same time – photoacoustic, near-infrared (NIR) optical imaging, and photothermal properties, in a versatile and stable core–shell silica-polyethylene glycol (PEG) nanoparticle architecture.

Materials and methods: We synthesized core–shell silica-PEG nanoparticles by a one-pot direct micelles approach. Fluorescence emission and photoacoustic and photothermal properties were obtained at the same time by appropriate doping with triethoxysilane-derivatized cyanine 5.5 (Cy5.5) and cyanine 7 (Cy7) dyes. The performances of these nanoprobes were measured in vitro, using nanoparticle suspensions in phosphate-buffered saline and blood, dedicated phantoms, and after incubation with MDA-MB-231 cells.

Results: We obtained core–shell silica-PEG nanoparticles endowed with very high colloidal stability in water and in biological environment, with absorption and fluorescence emission in the NIR field. The presence of Cy5.5 and Cy7 dyes made it possible to reach a more reproducible and higher doping regime, producing fluorescence emission at a single excitation wavelength in two different channels, owing to the energy transfer processes within the nanoparticle. The nanoarchitecture and the presence of both Cy5.5 and Cy7 dyes provided a favorable agreement between fluorescence emission and quenching, to achieve optical imaging and photoacoustic and photothermal properties.

Conclusion: We obtained rationally designed nanoparticles with outstanding stability in biological environment. At appropriate doping regimes, the presence of Cy5.5 and Cy7 dyes allowed us to tune fluorescence emission in the NIR for optical imaging and to exploit quenching processes for photoacoustic and photothermal capabilities. These nanostructures are promising in vivo theranostic tools for the near future.

No MeSH data available.


Fluorescence cell imaging.Notes: MDA-MB-231 cells were incubated with NIR-PluS NPs (NP-7; 100 nM) at 37°C for 24 hours, to allow NIR-PluS NP cell internalization before microscopy analysis. Representative cell images are shown. DAPI staining was carried out to visualize cell nuclei, which appear in blue, while NIR-PluS NPs appear in red. (A) Bright field image; (B) DAPI nuclear staining; (C) fluorescence emission; and (D) overlaid images (bar =20 µm).Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles.
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f3-ijn-11-4865: Fluorescence cell imaging.Notes: MDA-MB-231 cells were incubated with NIR-PluS NPs (NP-7; 100 nM) at 37°C for 24 hours, to allow NIR-PluS NP cell internalization before microscopy analysis. Representative cell images are shown. DAPI staining was carried out to visualize cell nuclei, which appear in blue, while NIR-PluS NPs appear in red. (A) Bright field image; (B) DAPI nuclear staining; (C) fluorescence emission; and (D) overlaid images (bar =20 µm).Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles.

Mentions: After the general photophysical characterization of our NPs, we performed fluorescence imaging using the MDA-MB-231 epithelial tumor cells that we conceived as model systems with the aim to preliminarily assess (in vitro) potential applications in PTT, in response to a 680 nm excitation source. First of all, cell cultures were incubated with the NIR-PluS NPs (NP-7 100 nM), and microscopy analyses demonstrated that cells were effective in NIR-PluS NP uptake and could be easily visualized with imaging modality (Figure 3).


Multimodal near-infrared-emitting PluS Silica nanoparticles with fluorescent, photoacoustic, and photothermal capabilities
Fluorescence cell imaging.Notes: MDA-MB-231 cells were incubated with NIR-PluS NPs (NP-7; 100 nM) at 37°C for 24 hours, to allow NIR-PluS NP cell internalization before microscopy analysis. Representative cell images are shown. DAPI staining was carried out to visualize cell nuclei, which appear in blue, while NIR-PluS NPs appear in red. (A) Bright field image; (B) DAPI nuclear staining; (C) fluorescence emission; and (D) overlaid images (bar =20 µm).Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles.
© Copyright Policy
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036595&req=5

f3-ijn-11-4865: Fluorescence cell imaging.Notes: MDA-MB-231 cells were incubated with NIR-PluS NPs (NP-7; 100 nM) at 37°C for 24 hours, to allow NIR-PluS NP cell internalization before microscopy analysis. Representative cell images are shown. DAPI staining was carried out to visualize cell nuclei, which appear in blue, while NIR-PluS NPs appear in red. (A) Bright field image; (B) DAPI nuclear staining; (C) fluorescence emission; and (D) overlaid images (bar =20 µm).Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles.
Mentions: After the general photophysical characterization of our NPs, we performed fluorescence imaging using the MDA-MB-231 epithelial tumor cells that we conceived as model systems with the aim to preliminarily assess (in vitro) potential applications in PTT, in response to a 680 nm excitation source. First of all, cell cultures were incubated with the NIR-PluS NPs (NP-7 100 nM), and microscopy analyses demonstrated that cells were effective in NIR-PluS NP uptake and could be easily visualized with imaging modality (Figure 3).

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: The aim of the present study was to develop nanoprobes with theranostic features, including – at the same time – photoacoustic, near-infrared (NIR) optical imaging, and photothermal properties, in a versatile and stable core–shell silica-polyethylene glycol (PEG) nanoparticle architecture.

Materials and methods: We synthesized core–shell silica-PEG nanoparticles by a one-pot direct micelles approach. Fluorescence emission and photoacoustic and photothermal properties were obtained at the same time by appropriate doping with triethoxysilane-derivatized cyanine 5.5 (Cy5.5) and cyanine 7 (Cy7) dyes. The performances of these nanoprobes were measured in vitro, using nanoparticle suspensions in phosphate-buffered saline and blood, dedicated phantoms, and after incubation with MDA-MB-231 cells.

Results: We obtained core–shell silica-PEG nanoparticles endowed with very high colloidal stability in water and in biological environment, with absorption and fluorescence emission in the NIR field. The presence of Cy5.5 and Cy7 dyes made it possible to reach a more reproducible and higher doping regime, producing fluorescence emission at a single excitation wavelength in two different channels, owing to the energy transfer processes within the nanoparticle. The nanoarchitecture and the presence of both Cy5.5 and Cy7 dyes provided a favorable agreement between fluorescence emission and quenching, to achieve optical imaging and photoacoustic and photothermal properties.

Conclusion: We obtained rationally designed nanoparticles with outstanding stability in biological environment. At appropriate doping regimes, the presence of Cy5.5 and Cy7 dyes allowed us to tune fluorescence emission in the NIR for optical imaging and to exploit quenching processes for photoacoustic and photothermal capabilities. These nanostructures are promising in vivo theranostic tools for the near future.

No MeSH data available.