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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.


Photothermal properties of NIR-PluS NPs.Notes: (A) Temperature change (∆ temperature) of aqueous suspension of NIR-PluS NP preparations at different concentrations upon irradiation with 808 nm laser (36 W/cm2) for 1 minute. (B) Temperature change of aqueous suspensions of NIR-PluS NPs (NP-4 and NP-7, 0.1 µM), in comparison to the control solution, upon irradiation with 808 nm laser (36 W/cm2). The local temperature was measured by an infrared thermal camera and plotted as a function of the irradiation time.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; NP, nanoparticle; Cy5.5, cyanine 5.5; Cy7, cyanine 7; s, seconds.
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f5-ijn-11-4865: Photothermal properties of NIR-PluS NPs.Notes: (A) Temperature change (∆ temperature) of aqueous suspension of NIR-PluS NP preparations at different concentrations upon irradiation with 808 nm laser (36 W/cm2) for 1 minute. (B) Temperature change of aqueous suspensions of NIR-PluS NPs (NP-4 and NP-7, 0.1 µM), in comparison to the control solution, upon irradiation with 808 nm laser (36 W/cm2). The local temperature was measured by an infrared thermal camera and plotted as a function of the irradiation time.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; NP, nanoparticle; Cy5.5, cyanine 5.5; Cy7, cyanine 7; s, seconds.

Mentions: Light-generated heat can also be advantageously used in therapy, and NIR light has been conventionally used for the in vivo PTT treatment of tumors under skin and within tissues, because of its deep penetration and reduced absorption through the high scattering tissue media. In this context, we have evaluated the photothermal capabilities of NIR-PluS NPs, looking at the temperature increase of their aqueous suspensions at different concentrations upon 1-minute irradiation with an 808 nm continuous wave diode laser with an intensity of 36 W/cm2 (Figure 5A). In turn, Figure 5B depicts the temperature increase of NP-4 and NP-7 suspensions at the lowest concentrations (0.1 µM) as a function of irradiation time. In particular, the presence of the Cy7-doping dye granted photothermal properties to the NIR-PluS NP. After 1 minute of irradiation time, a temperature change of 35.5°C was measured with NP-4 (1 µM) characterized by a 1% Cy7 doping. In contrast, because of the absence of absorption at the excitation wavelength, no significant temperature change was observed when sample NP-3 with 5% Cy5.5 doping was irradiated in the same conditions. Consistently, multiple-doped NIR Plus NPs, NP-5, NP-6, and NP-7, showed an intermediate behavior according to the absorption properties at 808 nm.


Multimodal near-infrared-emitting PluS Silica nanoparticles with fluorescent, photoacoustic, and photothermal capabilities
Photothermal properties of NIR-PluS NPs.Notes: (A) Temperature change (∆ temperature) of aqueous suspension of NIR-PluS NP preparations at different concentrations upon irradiation with 808 nm laser (36 W/cm2) for 1 minute. (B) Temperature change of aqueous suspensions of NIR-PluS NPs (NP-4 and NP-7, 0.1 µM), in comparison to the control solution, upon irradiation with 808 nm laser (36 W/cm2). The local temperature was measured by an infrared thermal camera and plotted as a function of the irradiation time.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; NP, nanoparticle; Cy5.5, cyanine 5.5; Cy7, cyanine 7; s, seconds.
© Copyright Policy
Related In: Results  -  Collection

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

f5-ijn-11-4865: Photothermal properties of NIR-PluS NPs.Notes: (A) Temperature change (∆ temperature) of aqueous suspension of NIR-PluS NP preparations at different concentrations upon irradiation with 808 nm laser (36 W/cm2) for 1 minute. (B) Temperature change of aqueous suspensions of NIR-PluS NPs (NP-4 and NP-7, 0.1 µM), in comparison to the control solution, upon irradiation with 808 nm laser (36 W/cm2). The local temperature was measured by an infrared thermal camera and plotted as a function of the irradiation time.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; NP, nanoparticle; Cy5.5, cyanine 5.5; Cy7, cyanine 7; s, seconds.
Mentions: Light-generated heat can also be advantageously used in therapy, and NIR light has been conventionally used for the in vivo PTT treatment of tumors under skin and within tissues, because of its deep penetration and reduced absorption through the high scattering tissue media. In this context, we have evaluated the photothermal capabilities of NIR-PluS NPs, looking at the temperature increase of their aqueous suspensions at different concentrations upon 1-minute irradiation with an 808 nm continuous wave diode laser with an intensity of 36 W/cm2 (Figure 5A). In turn, Figure 5B depicts the temperature increase of NP-4 and NP-7 suspensions at the lowest concentrations (0.1 µM) as a function of irradiation time. In particular, the presence of the Cy7-doping dye granted photothermal properties to the NIR-PluS NP. After 1 minute of irradiation time, a temperature change of 35.5°C was measured with NP-4 (1 µM) characterized by a 1% Cy7 doping. In contrast, because of the absence of absorption at the excitation wavelength, no significant temperature change was observed when sample NP-3 with 5% Cy5.5 doping was irradiated in the same conditions. Consistently, multiple-doped NIR Plus NPs, NP-5, NP-6, and NP-7, showed an intermediate behavior according to the absorption properties at 808 nm.

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.