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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.


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Photothermal ablation of MDA-MB-231 cells in vitro using NIR-PluS NPs.Notes: Cells were incubated with NIR-PluS NPs (NP-4, 100 nM) at 37°C for 24 hours, to allow NIR-PluS NP cell internalization before photothermal heating treatment (irradiation time: 1 minute, 36 W/cm2 at 808 nm). After an additional 24 hours of culture cell viability was assessed in all the different culture conditions, as indicated. Data are expressed as mean ± SD of three independent experiments. *P<0.05 with respect to control cells.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; NP, nanoparticle.
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f6-ijn-11-4865: Photothermal ablation of MDA-MB-231 cells in vitro using NIR-PluS NPs.Notes: Cells were incubated with NIR-PluS NPs (NP-4, 100 nM) at 37°C for 24 hours, to allow NIR-PluS NP cell internalization before photothermal heating treatment (irradiation time: 1 minute, 36 W/cm2 at 808 nm). After an additional 24 hours of culture cell viability was assessed in all the different culture conditions, as indicated. Data are expressed as mean ± SD of three independent experiments. *P<0.05 with respect to control cells.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; NP, nanoparticle.

Mentions: As a result, NP-4 sample had a heating profile matching more efficiently our experimental setup, with an improved thermal efficiency with respect to the other samples. For these reasons, we have chosen the sample NP-4 for the preliminary evaluation in vitro of the PTT performance with our equipment. For this purpose, MDA-MB-231 cells were incubated with NIR-PluS NPs (NP-4; 100 nM) for 24 hours and then exposed to an 808 nm continuous wave diode laser, operating at 36 W/cm2, for 1 minute. After an additional 24 hours of culture, the cell viability difference between control cells and cells incubated with NIR-Plus NPs was ∼43% (P<0.01) after light treatment (Figure 6). In contrast, we observe only a modest decrease in cell viability (∼10%, P<0.01) after 48 hours of exposure at the dose of 100 nM of NPs but without light treatment. In cells without NP incubation no effect of irradiation was observed (viability =99% of nonirradiated controls). Therefore, these results, while they confirm the lack of cell toxicity of the silica NPs,33 clearly show that cell death was induced by the photothermal effect of NIR-PluS NPs.


Multimodal near-infrared-emitting PluS Silica nanoparticles with fluorescent, photoacoustic, and photothermal capabilities
Photothermal ablation of MDA-MB-231 cells in vitro using NIR-PluS NPs.Notes: Cells were incubated with NIR-PluS NPs (NP-4, 100 nM) at 37°C for 24 hours, to allow NIR-PluS NP cell internalization before photothermal heating treatment (irradiation time: 1 minute, 36 W/cm2 at 808 nm). After an additional 24 hours of culture cell viability was assessed in all the different culture conditions, as indicated. Data are expressed as mean ± SD of three independent experiments. *P<0.05 with respect to control cells.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; NP, nanoparticle.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5036595&req=5

f6-ijn-11-4865: Photothermal ablation of MDA-MB-231 cells in vitro using NIR-PluS NPs.Notes: Cells were incubated with NIR-PluS NPs (NP-4, 100 nM) at 37°C for 24 hours, to allow NIR-PluS NP cell internalization before photothermal heating treatment (irradiation time: 1 minute, 36 W/cm2 at 808 nm). After an additional 24 hours of culture cell viability was assessed in all the different culture conditions, as indicated. Data are expressed as mean ± SD of three independent experiments. *P<0.05 with respect to control cells.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; NP, nanoparticle.
Mentions: As a result, NP-4 sample had a heating profile matching more efficiently our experimental setup, with an improved thermal efficiency with respect to the other samples. For these reasons, we have chosen the sample NP-4 for the preliminary evaluation in vitro of the PTT performance with our equipment. For this purpose, MDA-MB-231 cells were incubated with NIR-PluS NPs (NP-4; 100 nM) for 24 hours and then exposed to an 808 nm continuous wave diode laser, operating at 36 W/cm2, for 1 minute. After an additional 24 hours of culture, the cell viability difference between control cells and cells incubated with NIR-Plus NPs was ∼43% (P<0.01) after light treatment (Figure 6). In contrast, we observe only a modest decrease in cell viability (∼10%, P<0.01) after 48 hours of exposure at the dose of 100 nM of NPs but without light treatment. In cells without NP incubation no effect of irradiation was observed (viability =99% of nonirradiated controls). Therefore, these results, while they confirm the lack of cell toxicity of the silica NPs,33 clearly show that cell death was induced by the photothermal effect of NIR-PluS NPs.

View Article: PubMed Central - PubMed

ABSTRACT

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

Materials and methods: We synthesized core&ndash;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&ndash;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.


Related in: MedlinePlus