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Co-enhancement of fluorescence and singlet oxygen generation by silica-coated gold nanorods core-shell nanoparticle.

Ke X, Wang D, Chen C, Yang A, Han Y, Ren L, Li D, Wang H - Nanoscale Res Lett (2014)

Bottom Line: Metal-enhanced fluorescence (MEF) as a newly recognized technology has been attracting considerable attention and is widely used in fluorescence-based technology.In this paper, we reported a novel distance-dependent MEF and metal-enhanced singlet oxygen generation phenomenon based on silica-coated gold nanorods (AuNRs@SiO2) core-shell structure with tetra-substituted carboxyl aluminum phthalocyanine (AlC4Pc) that serve as both fluorophore and photosensitizer.When the AlC4Pc was linked on the surface of AuNRs@SiO2, the fluorescence intensity and singlet oxygen productivity varied with the thickness difference of silica shell from 2.1 to 28.6 nm.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomaterials, College of Materials, Xiamen University, Xiamen, 361005, People's Republic of China, kcc2691@126.com.

ABSTRACT
Metal-enhanced fluorescence (MEF) as a newly recognized technology has been attracting considerable attention and is widely used in fluorescence-based technology. In this paper, we reported a novel distance-dependent MEF and metal-enhanced singlet oxygen generation phenomenon based on silica-coated gold nanorods (AuNRs@SiO2) core-shell structure with tetra-substituted carboxyl aluminum phthalocyanine (AlC4Pc) that serve as both fluorophore and photosensitizer. When the AlC4Pc was linked on the surface of AuNRs@SiO2, the fluorescence intensity and singlet oxygen productivity varied with the thickness difference of silica shell from 2.1 to 28.6 nm. The co-enhancement effect reached the maximum of 7-fold and 2.1-fold, respectively, when the separation distance was 10.6 nm. These unique characteristics make the prepared core-shell nanoparticles promising for MEF-based biological imaging and photodynamics therapy.

No MeSH data available.


Related in: MedlinePlus

Absorption and fluorescence spectra, normalized absorbance, and fluorescence spectra. (a) Absorption and fluorescence spectra of AlC4Pc; (b) normalized absorbance of AuNRs@SiO2-AlC4Pc with different shell thickness; and (c) fluorescence spectra of original AlC4Pc and every supernatant. Inset: fluorescence standard curve of AlC4Pc over the concentration range 1 to 20 μM.
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Fig3: Absorption and fluorescence spectra, normalized absorbance, and fluorescence spectra. (a) Absorption and fluorescence spectra of AlC4Pc; (b) normalized absorbance of AuNRs@SiO2-AlC4Pc with different shell thickness; and (c) fluorescence spectra of original AlC4Pc and every supernatant. Inset: fluorescence standard curve of AlC4Pc over the concentration range 1 to 20 μM.

Mentions: The AlC4Pc used in this study is one of the second generation photosensitizers that have good optical properties for near infrared fluorescence imaging [26]. The absorption and fluorescence emission spectra of AlC4Pc were presented in Figure 3a; AlC4Pc displayed two absorption bands located at 360 nm (B-band) and 685 nm (Q-band), and the fluorescence band was centered at 695 nm. This Q-band fitted well for PDT applications, as red light is commonly used in PDT for its better penetration into the tissue [27]. The absorption spectra of the obtained AuNRs showed two typical surface plasmon resonances (SPR) bands with the transverse one centered at 515 nm and the longitudinal one centered at 668 nm. Moreover, the longitudinal SPR band underwent an obvious red shift from 5 to 22 nm after coating the surface with silica shell (Figure 3b). This spectral displacement could be attributed to the increased in the effective refractive index of the medium around the AuNRs [24]. After successfully linking of AlC4Pc molecules, the sharp absorption peak of AlC4Pc has little influence on AuNRs because the amount of AlC4Pc linked on each nanoparticle was controlled as low as possible to avoid the self-quenching. To calculate the amount of unloaded AlC4Pc, the fluorescence intensities of the supernatants and the original AlC4Pc solution were analyzed by the standard curve (Figure 3c). It was indicated that the average number of AlC4Pc molecules linked to each nanoparticle was 38.Figure 3


Co-enhancement of fluorescence and singlet oxygen generation by silica-coated gold nanorods core-shell nanoparticle.

Ke X, Wang D, Chen C, Yang A, Han Y, Ren L, Li D, Wang H - Nanoscale Res Lett (2014)

Absorption and fluorescence spectra, normalized absorbance, and fluorescence spectra. (a) Absorption and fluorescence spectra of AlC4Pc; (b) normalized absorbance of AuNRs@SiO2-AlC4Pc with different shell thickness; and (c) fluorescence spectra of original AlC4Pc and every supernatant. Inset: fluorescence standard curve of AlC4Pc over the concentration range 1 to 20 μM.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Fig3: Absorption and fluorescence spectra, normalized absorbance, and fluorescence spectra. (a) Absorption and fluorescence spectra of AlC4Pc; (b) normalized absorbance of AuNRs@SiO2-AlC4Pc with different shell thickness; and (c) fluorescence spectra of original AlC4Pc and every supernatant. Inset: fluorescence standard curve of AlC4Pc over the concentration range 1 to 20 μM.
Mentions: The AlC4Pc used in this study is one of the second generation photosensitizers that have good optical properties for near infrared fluorescence imaging [26]. The absorption and fluorescence emission spectra of AlC4Pc were presented in Figure 3a; AlC4Pc displayed two absorption bands located at 360 nm (B-band) and 685 nm (Q-band), and the fluorescence band was centered at 695 nm. This Q-band fitted well for PDT applications, as red light is commonly used in PDT for its better penetration into the tissue [27]. The absorption spectra of the obtained AuNRs showed two typical surface plasmon resonances (SPR) bands with the transverse one centered at 515 nm and the longitudinal one centered at 668 nm. Moreover, the longitudinal SPR band underwent an obvious red shift from 5 to 22 nm after coating the surface with silica shell (Figure 3b). This spectral displacement could be attributed to the increased in the effective refractive index of the medium around the AuNRs [24]. After successfully linking of AlC4Pc molecules, the sharp absorption peak of AlC4Pc has little influence on AuNRs because the amount of AlC4Pc linked on each nanoparticle was controlled as low as possible to avoid the self-quenching. To calculate the amount of unloaded AlC4Pc, the fluorescence intensities of the supernatants and the original AlC4Pc solution were analyzed by the standard curve (Figure 3c). It was indicated that the average number of AlC4Pc molecules linked to each nanoparticle was 38.Figure 3

Bottom Line: Metal-enhanced fluorescence (MEF) as a newly recognized technology has been attracting considerable attention and is widely used in fluorescence-based technology.In this paper, we reported a novel distance-dependent MEF and metal-enhanced singlet oxygen generation phenomenon based on silica-coated gold nanorods (AuNRs@SiO2) core-shell structure with tetra-substituted carboxyl aluminum phthalocyanine (AlC4Pc) that serve as both fluorophore and photosensitizer.When the AlC4Pc was linked on the surface of AuNRs@SiO2, the fluorescence intensity and singlet oxygen productivity varied with the thickness difference of silica shell from 2.1 to 28.6 nm.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomaterials, College of Materials, Xiamen University, Xiamen, 361005, People's Republic of China, kcc2691@126.com.

ABSTRACT
Metal-enhanced fluorescence (MEF) as a newly recognized technology has been attracting considerable attention and is widely used in fluorescence-based technology. In this paper, we reported a novel distance-dependent MEF and metal-enhanced singlet oxygen generation phenomenon based on silica-coated gold nanorods (AuNRs@SiO2) core-shell structure with tetra-substituted carboxyl aluminum phthalocyanine (AlC4Pc) that serve as both fluorophore and photosensitizer. When the AlC4Pc was linked on the surface of AuNRs@SiO2, the fluorescence intensity and singlet oxygen productivity varied with the thickness difference of silica shell from 2.1 to 28.6 nm. The co-enhancement effect reached the maximum of 7-fold and 2.1-fold, respectively, when the separation distance was 10.6 nm. These unique characteristics make the prepared core-shell nanoparticles promising for MEF-based biological imaging and photodynamics therapy.

No MeSH data available.


Related in: MedlinePlus