Correlation between surface composition and luminescence of nanocrystalline silicon particles dispersed in pure water

Hiruoka, Masaki; Sato, Keisuke; Hirakuri, Kenji

doi:10.1063/1.2756048

Cited by 5 publications

(3 citation statements)

References 18 publications

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“…Since the yields of oxygen radicals were reduced by UV exposure, the mechanism may be associated with the oxidative states of Si-QDs. Our previous study showed that the surface condition of Si-QDs was changed by oxidation [38,39]. In addition, their surface potentials were reduced by UV exposure (data not shown).…”

Section: Toxicity Mechanism Of Silicon Quantum Dotsmentioning

confidence: 90%

“…Silicon quantum dots (Si-QDs) were prepared with the methods described previously [38,39], and purified with pure water. The photoluminescence spectra of Si-QDs in phosphate buffered saline (PBS) were detected by using a fluorescence spectrometer, FP-6500 (Jasco, Japan).…”

Section: Quantum Dot Synthesismentioning

confidence: 99%

“…Some tens of mg per batch were produced in the method. The Si-QDs were water-soluble due to hydroxyl group on their surface [38], and their PL was made stable by oxygen-passivation [39] and could be tuned by controlling the etching time.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2008

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Semiconductor quantum dots (QDs) hold some advantages over conventional organic fluorescent dyes. Due to these advantages, they are becoming increasingly popular in the field of bioimaging. However, recent work suggests that cadmium based QDs affect cellular activity. As a substitute for cadmium based QDs, we have developed photoluminescent stable silicon quantum dots (Si-QDs) with a passive-oxidation technique. Si-QDs (size: 6.5 ± 1.5 nm) emit green light, and they have been used as biological labels for living cell imaging. In order to determine the minimum concentration for cytotoxicity, we investigated the response of HeLa cells. We have shown that the toxicity of Si-QDs was not observed at 112 µg ml(-1) and that Si-QDs were less toxic than CdSe-QDs at high concentration in mitochondrial assays and with lactate dehydrogenase (LDH) assays. Especially under UV exposure, Si-QDs were more than ten times safer than CdSe-QDs. We suggest that one mechanism for the cytotoxicity is that Si-QDs can generate oxygen radicals and these radicals are associated with membrane damages. This work has demonstrated the suitability of Si-QDs for bioimaging in lower concentration, and their cytotoxicity and one toxicity mechanism at high concentration.

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Section: Toxicity Mechanism Of Silicon Quantum Dotsmentioning

confidence: 90%

Section: Quantum Dot Synthesismentioning

confidence: 99%

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

et al. 2008

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Size-Tunable Silicon/Iron Oxide Hybrid Nanoparticles with Fluorescence, Superparamagnetism, and Biocompatibility

et al. 2011

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Magnetic/fluorescent composite materials have become one of the most important tools in the imaging modality in vivo using magnetic resonance imaging (MRI) monitoring and fluorescence optical imaging. We report herein on a simplified procedure to synthesize hybrid nanoparticles (HNPs) that combine silicon and magnetic iron oxides consisting of magnetite (Fe(3)O(4)) and maghemite (γ-Fe(2)O(3)). Intriguingly, our unique synthetic approach can control magnetic and optical behaviors by reducing the particle size, demonstrating that the HNPs with the mean diameter of 3.0 nm exhibit superparamagnetic behavior and green fluorescence in an aqueous solution, ambient air, and a cellular environment, whereas the HNPs with the mean diameter more than 5.0 nm indicate ferromagnetic behavior without fluorescence. Additionally, both HNPs with different diameters possess excellent magnetic responsivity for external applied magnetic field and good biocompatibility due to the low cytotoxicity. Our biocompatible HNPs with the superparamagnetism can provide an attractive approach for diagnostic imaging system in vivo.

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Production of nanocrystalline silicon layers using the plasma enhanced chemical vapor deposition from the gas phase of silicon tetrafluoride

et al. 2009

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Correlation between surface composition and luminescence of nanocrystalline silicon particles dispersed in pure water

Abstract: Improvement of luminescence degradation in pure water of nanocrystalline silicon particles covered by a hydrogenated amorphous carbon layer

Cited by 5 publications

References 18 publications

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

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

Size-Tunable Silicon/Iron Oxide Hybrid Nanoparticles with Fluorescence, Superparamagnetism, and Biocompatibility

Production of nanocrystalline silicon layers using the plasma enhanced chemical vapor deposition from the gas phase of silicon tetrafluoride

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