Ultrasmall Gold Cluster Arrays Encapsulated in Silica Nanospheres: Applications in Fluorescence Imaging and Catalysis

Samanta, Anupam; Dhar, Basab Bijayi; Devi, Rashmita

doi:10.1021/jp2093737

Cited by 45 publications

(41 citation statements)

References 33 publications

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“…Fluorescent AuNCs consisting of 25 gold atoms were prepared by a protein-directed biomimetic synthesis method with a red emission and a quantum yield (QY) of around 6% [57]. Due to its ultrasmall size (< 1 nm), AuNCs are difficult to separate and purify [59]. To solve this problem, silica nanoparticles were used to entrap AuNCs by a modified Stöber method [35].…”

Section: Resultsmentioning

confidence: 99%

Photosensitizer-conjugated silica-coated gold nanoclusters for fluorescence imaging-guided photodynamic therapy

Huang¹,

Lin²,

Wang³

et al. 2013

Biomaterials

207

121

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Multifunctional theranostics have recently been intensively explored to optimize the efficacy and safety of therapeutic regimens. In this work, a photo-theranostic agent based on chlorin e6 (Ce6) photosensitizer-conjugated silica-coated gold nanoclusters (AuNCs@SiO2-Ce6) is strategically designed and prepared for fluorescence imaging-guided photodynamic therapy (PDT). The AuNCs@SiO2-Ce6 shows the following features: i) high Ce6 photosensitizer loading; ii) no non-specific release of Ce6 during its circulation; iii) significantly enhanced cellular uptake efficiency of Ce6, offering a remarkably improved photodynamic therapeutic efficacy compared to free Ce6; iv) subcellular characterization of the nanoformula via both the fluorescence of Ce6 and plasmon luminescence of AuNCs; v) fluorescence imaging-guided photodynamic therapy (PDT). This photo-theranostics owns good stability, high water dispersibility and solubility, non-cytotoxicity, and good biocompatibility, thus facilitating its biomedical applications, particularly for multi-modal optical, CT and photoacoustic (PA) imaging guided PDT or sonodynamic therapy.

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Section: Resultsmentioning

confidence: 99%

Photosensitizer-conjugated silica-coated gold nanoclusters for fluorescence imaging-guided photodynamic therapy

Huang¹,

Lin²,

Wang³

et al. 2013

Biomaterials

207

121

View full text Add to dashboard Cite

show abstract

“…However, the clear therapeutic and imaging potential of AuQDs in vivo has been undermined by their unfavorable biointeractions and lack of stability in aqueous solvents (5,7). In biological environments AuQDs tend to aggregate rapidly, reverting to larger gold nanoparticles (AuNPs) (8) and/or bind to protein, which negatively affects their cytotoxicity (7). To retain their advantages, AuQDs require a protective, stabilizing framework that allows proficient biological interactions.…”

mentioning

confidence: 99%

Gold–silica quantum rattles for multimodal imaging and therapy

Hembury

Chiappini

Bertazzo

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

111

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Gold quantum dots exhibit distinctive optical and magnetic behaviors compared with larger gold nanoparticles. However, their unfavorable interaction with living systems and lack of stability in aqueous solvents has so far prevented their adoption in biology and medicine. Here, a simple synthetic pathway integrates gold quantum dots within a mesoporous silica shell, alongside larger gold nanoparticles within the shell's central cavity. This "quantum rattle" structure is stable in aqueous solutions, does not elicit cell toxicity, preserves the attractive near-infrared photonics and paramagnetism of gold quantum dots, and enhances the drug-carrier performance of the silica shell. In vivo, the quantum rattles reduced tumor burden in a single course of photothermal therapy while coupling three complementary imaging modalities: near-infrared fluorescence, photoacoustic, and magnetic resonance imaging. The incorporation of gold within the quantum rattles significantly enhanced the drug-carrier performance of the silica shell. This innovative material design based on the mutually beneficial interaction of gold and silica introduces the use of gold quantum dots for imaging and therapeutic applications.nanomedicine | hybrid nanoparticle | cancer nanotechnology | gold quantum dots | mesoporous silica A lthough gold's potential in nanotechnology has been recognized for many decades (1, 2), new insights into the unique properties of gold nanoparticles (NPs) of less than 2 nm have just recently started to emerge (3, 4). Such extremely small gold NPs could be transformative for a broad set of applications ranging from energy production and storage to catalysis and health care (3). As the size of gold NPs decreases below 2 nm, the quantization of their conduction band leads to molecule-like properties (3). These quantum-sized gold NPs (or gold quantum dots, AuQDs) absorb light in the near-infrared (NIR) biological window (650-900 nm) (2) and convert it into photons and heat (5). Furthermore, whereas bulk gold is diamagnetic, some AuQDs exhibit magnetic properties (4, 6). However, the clear therapeutic and imaging potential of AuQDs in vivo has been undermined by their unfavorable biointeractions and lack of stability in aqueous solvents (5, 7). In biological environments AuQDs tend to aggregate rapidly, reverting to larger gold nanoparticles (AuNPs) (8) and/or bind to protein, which negatively affects their cytotoxicity (7). To retain their advantages, AuQDs require a protective, stabilizing framework that allows proficient biological interactions.Recently, new emphasis has been placed on hybrid NP systems, where multiple nanomaterials are assembled to create multimodal systems that exhibit the combined qualities of the component modules (9-11). These constructs promise to integrate various functionalities by incorporating different nanomaterials into a single, efficient, multimodal system (12, 13). However, these systems usually accumulate the specific functionalities of their component modules through multiple steps in their ...

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“…Hence sintering would be better controlled than in a core-shell architecture. Hence further work was carried out by a propyl ammonium decorated alkyl thiol ligand [30].…”

Section: Resultsmentioning

confidence: 99%

“…We have already synthesised Au and Pd ultra small clusters encapsulated in silica by this method [29,30]. In all the cases, we could achieve resistance to sintering to a large extent.…”

Section: Resultsmentioning

confidence: 99%

“…Thiol ligand (N,N,NTripropyl(11-mercaptoundecyl)ammonium Chloride) was synthesised by the method reported elsewhere [30]. (0.42 mmol) of thiol in methanol was added to the AgNO 3 solution with constant stirring at moderate speed for 2 h. The colour of the resulting solution instantaneously turned to deep orange-yellow.…”

Section: Synthesis Of Silver Ultra Small Clustersmentioning

confidence: 99%

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Encapsulation of ultra small metal clusters in silica: Evolution of the concept of nanoreactors and the case of Ag–Pd@SiO2 alloy catalyst

et al. 2015

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Ultrasmall Gold Cluster Arrays Encapsulated in Silica Nanospheres: Applications in Fluorescence Imaging and Catalysis

Cited by 45 publications

References 33 publications

Photosensitizer-conjugated silica-coated gold nanoclusters for fluorescence imaging-guided photodynamic therapy

Photosensitizer-conjugated silica-coated gold nanoclusters for fluorescence imaging-guided photodynamic therapy

Gold–silica quantum rattles for multimodal imaging and therapy

Encapsulation of ultra small metal clusters in silica: Evolution of the concept of nanoreactors and the case of Ag–Pd@SiO2 alloy catalyst

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