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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.


Related in: MedlinePlus

Synthesis and morphological characterization of NIR-PluS NPs.Notes: (A) Main chemical components; (B) schematic representation of NIR-PluS NPs synthesis; (C) representative DLS hydrodynamic diameter distribution in water; and (D) representative TEM image with core diameter distribution.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; TEM, transmission electron microscope; TEOS, tetraethyl orthosilicate; NP, nanoparticle; DLS, dynamic light scattering.
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f1-ijn-11-4865: Synthesis and morphological characterization of NIR-PluS NPs.Notes: (A) Main chemical components; (B) schematic representation of NIR-PluS NPs synthesis; (C) representative DLS hydrodynamic diameter distribution in water; and (D) representative TEM image with core diameter distribution.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; TEM, transmission electron microscope; TEOS, tetraethyl orthosilicate; NP, nanoparticle; DLS, dynamic light scattering.

Mentions: The synthetic scheme, applied for the preparation of core–shell silica-polyethylene glycol (PEG) dye-doped NPs, is shown in Figure 1. Preparation and morphological characterization were carried out adapting previously reported procedures.21,22 For the preparation of NIR-PluS NPs (Table 1), 100 mg of Pluronic F127 and the desired amount of alkoxysilane dye(s) were solubilized with a small amount (∼1.0 mL) of dichloromethane in an 8 mL glass scintillation vial. The solvent was then evaporated from the homogeneous solution under vacuum at room temperature. NaCl (68 mg) was added to the solid residue, and the mixture was solubilized at 25°C under magnetic stirring with 1,560 µL of 1.0 M acetic acid. Tetraethyl orthosilicate (180 µL, 0.8 mmol) was then added to the resulting aqueous homogeneous solution followed by chlorotrimethylsilane (10 µL, 0.08 mmol) after 180 minutes. The mixture was kept under stirring for 48 hours at 25°C before dialysis treatments. The dialysis purification steps were carried out versus water on a precise amount of NP solution (1,500 µL) finally diluted to a total volume of 10.0 mL with water. The final concentration of the NP solution was measured taking into account the volume after the dialysis.


Multimodal near-infrared-emitting PluS Silica nanoparticles with fluorescent, photoacoustic, and photothermal capabilities
Synthesis and morphological characterization of NIR-PluS NPs.Notes: (A) Main chemical components; (B) schematic representation of NIR-PluS NPs synthesis; (C) representative DLS hydrodynamic diameter distribution in water; and (D) representative TEM image with core diameter distribution.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; TEM, transmission electron microscope; TEOS, tetraethyl orthosilicate; NP, nanoparticle; DLS, dynamic light scattering.
© Copyright Policy
Related In: Results  -  Collection

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

f1-ijn-11-4865: Synthesis and morphological characterization of NIR-PluS NPs.Notes: (A) Main chemical components; (B) schematic representation of NIR-PluS NPs synthesis; (C) representative DLS hydrodynamic diameter distribution in water; and (D) representative TEM image with core diameter distribution.Abbreviations: NIR, near infrared; NIR-PluS NPs, NIR-emitting pluronic-silica nanoparticles; TEM, transmission electron microscope; TEOS, tetraethyl orthosilicate; NP, nanoparticle; DLS, dynamic light scattering.
Mentions: The synthetic scheme, applied for the preparation of core–shell silica-polyethylene glycol (PEG) dye-doped NPs, is shown in Figure 1. Preparation and morphological characterization were carried out adapting previously reported procedures.21,22 For the preparation of NIR-PluS NPs (Table 1), 100 mg of Pluronic F127 and the desired amount of alkoxysilane dye(s) were solubilized with a small amount (∼1.0 mL) of dichloromethane in an 8 mL glass scintillation vial. The solvent was then evaporated from the homogeneous solution under vacuum at room temperature. NaCl (68 mg) was added to the solid residue, and the mixture was solubilized at 25°C under magnetic stirring with 1,560 µL of 1.0 M acetic acid. Tetraethyl orthosilicate (180 µL, 0.8 mmol) was then added to the resulting aqueous homogeneous solution followed by chlorotrimethylsilane (10 µL, 0.08 mmol) after 180 minutes. The mixture was kept under stirring for 48 hours at 25°C before dialysis treatments. The dialysis purification steps were carried out versus water on a precise amount of NP solution (1,500 µL) finally diluted to a total volume of 10.0 mL with water. The final concentration of the NP solution was measured taking into account the volume after the dialysis.

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.


Related in: MedlinePlus