Luminescent passive-oxidized silicon quantum dots as biological staining labels and their cytotoxicity effects at high concentration

Fujioka, Kouki; Hiruoka, Masaki; Sato, Keisuke; Manabe, Noriyoshi; Miyasaka, Ryosuke; Hanada, Sanshiro; Hoshino, Akihiro; Tilley, Richard D.; Manome, Yoshinobu; Hirakuri, Kenji; Yamamoto, Kenji

doi:10.1088/0957-4484/19/41/415102

Cited by 135 publications

(102 citation statements)

References 45 publications

(56 reference statements)

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“…Generally, it is considered that doses lower than 25 lgÁmL À1 silicon QDs are potentially 'safe' compared to other nanoparticles and thus high-dose toxicity effects require comprehensive investigation [22]. The concentrations of Si/SiO 2 QDs (25-200 lgÁmL…”

Section: Discussionmentioning

confidence: 99%

Silicon‐based quantum dots induce inflammation in human lung cells and disrupt extracellular matrix homeostasis

et al. 2015

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Quantum dots (QDs) are nanocrystalline semiconductor materials that have been tested for biological applications such as cancer therapy, cellular imaging and drug delivery, despite the serious lack of information of their effects on mammalian cells. The present study aimed to evaluate the potential of Si/SiO 2 QDs to induce an inflammatory response in MRC-5 human lung fibroblasts. Cells were exposed to different concentrations of Si/SiO 2 QDs (25-200 lgÁmL À1 ) for 24, 48, 72 and 96 h. The results obtained showed that uptake of QDs was dependent on biocorona formation and the stability of nanoparticles in various biological media (minimum essential medium without or with 10% fetal bovine serum). The cell membrane damage indicated by the increase in lactate dehydrogenase release after exposure to QDs was dose-and time-dependent. The level of lysosomes increased proportionally with the concentration of QDs, whereas an accumulation of autophagosomes was also observed. Cellular morphology was affected, as shown by the disruption of actin filaments. The enhanced release of nitric oxide and the increase in interleukin-6 and interleukin-8 protein expression suggested that nanoparticles triggered an inflammatory response in MRC-5 cells. QDs decreased the protein expression and enzymatic activity of matrix metalloproteinase (MMP)-2 and MMP-9 and also MMP-1 caseinase activity, whereas the protein levels of MMP-1 and tissue inhibitor of metalloproteinase-1 increased. The present study reveals for the first time that silicon-based QDs are able to generate inflammation in lung cells and cause an imbalance in extracellular matrix turnover through a differential regulation of MMPs and tissue inhibitor of metalloproteinase-1 protein expression.

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Section: Discussionmentioning

confidence: 99%

Silicon‐based quantum dots induce inflammation in human lung cells and disrupt extracellular matrix homeostasis

et al. 2015

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“…Recently, silicon quantum dots with photoluminescence quantum yields of over 60% have been demonstrated for organically capped silicon nanocrystals, with emission in the near-infrared range [31,32]. Other big challenges in making biocompatible SiQDs include the instability of their photoluminescence due to their fast oxidation rate in aqueous environments, and the difficulties involved in attaching hydrophilic molecules to the SiQD surface [33][34][35][36]. Optimal surface functionalization, such as capping the surface of the SiQD with NH 2 , SH, OH, acrylic acid, and alkyl groups, has been sought to produce water-dispersible SiQDs while maintaining spectral and colloidal stability [33][34][35][36].…”

Section: Fluorescent Silica Nanoparticlesmentioning

confidence: 99%

“…Other big challenges in making biocompatible SiQDs include the instability of their photoluminescence due to their fast oxidation rate in aqueous environments, and the difficulties involved in attaching hydrophilic molecules to the SiQD surface [33][34][35][36]. Optimal surface functionalization, such as capping the surface of the SiQD with NH 2 , SH, OH, acrylic acid, and alkyl groups, has been sought to produce water-dispersible SiQDs while maintaining spectral and colloidal stability [33][34][35][36]. Highly stable aqueous suspensions of SiQDs encapsulated in phospholipid micelles were prepared and applied as luminescent labels for pancreatic cancer cells [35].…”

Section: Fluorescent Silica Nanoparticlesmentioning

confidence: 99%

Nanomaterials in fluorescence-based biosensing

2009

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Fluorescence-based detection is the most common method utilized in biosensing because of its high sensitivity, simplicity, and diversity. In the era of nanotechnology, nanomaterials are starting to replace traditional organic dyes as detection labels because they offer superior optical properties, such as brighter fluorescence, wider selections of excitation and emission wavelengths, higher photostability, etc. Their size-or shape-controllable optical characteristics also facilitate the selection of diverse probes for higher assay throughput. Furthermore, the nanostructure can provide a solid support for sensing assays with multiple probe molecules attached to each nanostructure, simplifying assay design and increasing the labeling ratio for higher sensitivity. The current review summarizes the applications of nanomaterialsincluding quantum dots, metal nanoparticles, and silica nanoparticles-in biosensing using detection techniques such as fluorescence, fluorescence resonance energy transfer (FRET), fluorescence lifetime measurement, and multiphoton microscopy. The advantages nanomaterials bring to the field of biosensing are discussed. The review also points out the importance of analytical separations in the preparation of nanomaterials with fine optical and physical properties for biosensing. In conclusion, nanotechnology provides a great opportunity to analytical chemists to develop better sensing strategies, but also relies on modern analytical techniques to pave its way to practical applications.Keywords Nanomaterials . Quantum dots . Gold nanoparticle . Silica nanoparticle . Fluorescence . FRET . Biosensing OverviewSensitive detection of target analytes present at trace levels in biological samples often requires the labeling of reporter molecules with fluorescent dyes, because fluorescence detection is by far the dominant detection method in the field of sensing technology, due to its simplicity, the convenience of transducing the optical signal, the availability of organic dyes with diverse spectral properties, and the rapid advances made in optical imaging. However, it can be difficult to obtain a low detection limit in fluorescence detection due to the limited extinction coefficients or quantum yields of organic dyes and the low dye-toreporter molecule labeling ratio. The recent explosion of nanotechnology, leading to the development of materials with submicron-sized dimensions and unique optical properties, has opened up new horizons for fluorescence detection. Nanomaterials can be made from both inorganic and organic materials and are less than 100 nm in length

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“…Since 1990, when Canham [1] found silicon nanostructures were able to emit visible light, interest in nanoscale silicon structures has risen sharply throughout the wider scientific community [2][3][4][5][6][7][8][9][10][11]. Owing to their ability to emit red light and lack of toxicity [12,13], silicon quantum dots (Si-QDs), are deemed to be one of the best candidates as bio-labels for applications in bio-imaging. However, their full potential faces a major barrier in respect of their water solubility.…”

mentioning

confidence: 99%

Soft X‐ray induced oxidation on acrylic acid grafted luminescent silicon quantum dots in ultrahigh vacuum

Chao

Wang

Pietzsch

et al. 2011

Physica Status Solidi (a)

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Water soluble acrylic acid grafted luminescent silicon quantum dots (Si-QDs) were prepared by a simplified method. The resulting Si-QDs dissolved in water and showed stable strong luminescence with peaks at 436 and 604 nm. X-ray photoelectron spectroscopy (XPS) was employed to examine the surface electronic states after the synthesis. The co-existence of the Si2p and C1s core levels infers that the acrylic acid has been successfully grafted on the surface of silicon quantum dots. To fit the Si2p spectrum, four components were needed at 99.45, 100.28, 102.21 and 103.24 eV. The first component at 99.45 eV (I) was assigned to Si-Si within the silicon core of the Si-QDs. The second component at 100.28 eV (II) was from Si-C. The third at 102.21 eV (III) was a sub-oxide state and the fourth at 103.24 eV (IV) was from SiO 2 at Si-QDs surface. With an increase in exposure to soft X-ray photons, the intensity ratio of the two peaks within the Si2p region A and B increased from 0.5 to 1.4 while the peak A intensity decreased, and eventually a steady state was reached. This observation is explained in terms of photon-induced oxidation taking place within the surface dangling bonds. As the PL profile for Si-QDs is influenced by the degree of oxidation within the nanocrystal structure, the inducement of oxidation by soft X-rays will play a role in the range of potential applications where such materials could be used -especially within biomedical labelling.

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Luminescent passive-oxidized silicon quantum dots as biological staining labels and their cytotoxicity effects at high concentration

Cited by 135 publications

References 45 publications

Silicon‐based quantum dots induce inflammation in human lung cells and disrupt extracellular matrix homeostasis

Silicon‐based quantum dots induce inflammation in human lung cells and disrupt extracellular matrix homeostasis

Nanomaterials in fluorescence-based biosensing

Soft X‐ray induced oxidation on acrylic acid grafted luminescent silicon quantum dots in ultrahigh vacuum

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