Surfactant-Assisted Synthesis of Water-Soluble and Biocompatible Semiconductor Quantum Dot Micelles

Fan, Hongyou; Leve, Erik W.; Scullin, Chessa; Gabaldon, John; Tallant, D. R.; Bunge, Scott D.; Boyle, Tim; Wilson, Michael C.; Brinker, C. Jeffrey

doi:10.1021/nl050017l

Cited by 238 publications

(162 citation statements)

References 24 publications

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“…The water-soluble CTAB-coated CdSe/ZnS QDs were synthesized according to the protocols described by Fan et al [33] with necessary modification as follows. The surfactant aqueous solution was obtained by fully dissolving CTAB (1.652 g) in deionized water (45 mL) in an ultrasonic water bath (40 • C) for 20 min, making a 10 −3 dilution, and adjusting the pH to 9.5 with a 20% (w w −1 ) solution of NaOH.…”

Section: Synthesis and Characterization Of Ctab-coated Cdse/zns Qdsmentioning

confidence: 99%

Rapid detection of vegetable cooking oils adulterated with inedible used oil using fluorescence quenching method with aqueous CTAB-coated quantum dots

Xiong

et al. 2014

Sensors and Actuators B: Chemical

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a b s t r a c tVegetable cooking oils adulterated with inedible used oils or impure oils have posed a severe food safety problem. Current detection methods cannot meet the needs for rapid detection of adulterated oils on line or in field. Therefore, the objective of this research was to develop a rapid optical sensing method based on fluorescence quenching of CdSe/ZnS quantum dots (QDs) for identification of adulterated vegetable cooking oils. High quality hydrophilic photoluminescent nanoparticles were synthesized by encapsulating hydrophobic QDs into the micellar structure of an amphiphilic surfactant cetyltrimethyl ammonium bromide (CTAB) via phase transfer method. TEM, AFM, and fluorescence spectroscopy were used to characterize the prepared CTAB-coated QDs. Oil samples were first captured into the core of the twolayer-structural micelle and then the fluorescence of CTAB-coated QDs, working as fluorescence probes, was selectively quenched by components of the adulterated oils. Heavy metal ions and free radicals were presumed to be main quenchers. After quenching for 1 min, fluorescence intensity was measured and converted to quenching percentage to determine the adulteration concentration. The results showed that in comparison with oil-soluble QDs, water-soluble CTAB-coated QDs had a greater ability to identify oil adulteration. A good quantitative relationship between quenching percentage and adulteration concentration (y = 5.96x + 14.99; R 2 = 0.94) was obtained. The sensitive, simple and low-cost sensing method did not require sample pretreatment and could detect refined used oils at 0.4% or higher concentrations in soybean oil within 2 min, showing great potentials for rapid screening of used oils and quantitative analysis of used oil adulteration in field.

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Section: Synthesis and Characterization Of Ctab-coated Cdse/zns Qdsmentioning

confidence: 99%

Rapid detection of vegetable cooking oils adulterated with inedible used oil using fluorescence quenching method with aqueous CTAB-coated quantum dots

Xiong

et al. 2014

Sensors and Actuators B: Chemical

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“…In this study, myristyltrimethylammonium bromide (C 14 TAB), hexadecyltrimethylammonium bromide (C 16 TAB), or octadecyltrimethylammonium bromide (C 18 TAB) was utilized as a surfactant to produce the second layer on the outer surface of magnetic nanocrystals which led to high dispersion of nanocrystals in water. [46][47][48] Then, a silica precursor tetraethoxysilane (TEOS) hydrolyzed, condensed, and made a self-assembly with surfactant micelles to produce surfactant/silica complexes by S Low angle XRD patterns of samples MSNs-C 14 -2, MSNs-C 16 -2, and MSNs-C 18 -2 are shown in Figure 3A. A high-intensity diffraction peak of (100) and three additional well-resolved diffraction peaks of (110), (200), (210) are observed, which can be assigned to a two-dimensional hexagonal mesostructure (space group p6mm).…”

Section: Magnetic Silica Nanospheres With Highly Ordered Mesostructurementioning

confidence: 99%

Fabrication and Size‐Selective Bioseparation of Magnetic Silica Nanospheres with Highly Ordered Periodic Mesostructure

Zhang

Qiao

Jin

et al. 2008

Adv Funct Materials

180

124

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In this paper, we report a novel synthesis and selective bioseparation of the composite of Fe3O4 magnetic nanocrystals and highly ordered MCM‐41 type periodic mesoporous silica nanospheres. Monodisperse superparamagnetic Fe3O4 nanocrystals were synthesized by thermal decomposition of iron stearate in diol in an autoclave at low temperature. The synthesized nanocrystals were encapsulated in mesoporous silica nanospheres through the packing and self‐assembly of composite nanocrystal–surfactant micelles and surfactant/silica complex. Different from previous studies, the produced magnetic silica nanospheres (MSNs) possess not only uniform nanosize (90 ∼ 140 nm) but also a highly ordered mesostructure. More importantly, the pore size and the saturation magnetization values can be controlled by using different alkyltrimethylammonium bromide surfactants and changing the amount of Fe3O4 magnetic nanocrystals encapsulated, respectively. Binary adsorption and desorption of proteins cytochrome c (cyt c) and bovine serum albumin (BSA) demonstrate that MSNs are an effective and highly selective adsorbent for proteins with different molecular sizes. Small particle size, high surface area, narrow pore size distribution, and straight pores of MSNs are responsible for the high selective adsorption capacity and fast adsorption rates. High magnetization values and superparamagnetic property of MSNs provide a convenient means to remove nanoparticles from solution and make the re‐dispersion in solution quick following the withdrawal of an external magnetic field.

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“…A micellular and paramagnetic coating was applied to the QDs in order to make them MR-detectable, water-soluble, and biocompatible. 9,21 This micellular coating was composed of a pegylated phospholipid, PEG-DSPE (1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy-(poly(ethylene glycol))-2000]), and a paramagnetic lipid, Gd-DTPA-BSA (Gd-DTPA-bis(stearylamide). PEG-lipids are used commonly to stabilize liposomes for pharmaceutical applications because the PEG chains form a hydrophilic coating at the liposomal surface.…”

mentioning

confidence: 99%

Quantum Dots with a Paramagnetic Coating as a Bimodal Molecular Imaging Probe

et al. 2005

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MRI detectable and targeted quantum dots were developed. To that aim, quantum dots were coated with paramagnetic and pegylated lipids, which resulted in a relaxivity, r 1 , of nearly 2000 mM -1 s -1 per quantum dot. The quantum dots were functionalized by covalently linking rv 3-specific RGD peptides, and the specificity was assessed and confirmed on cultured endothelial cells. The bimodal character, the high relaxivity, and the specificity of this nanoparticulate probe make it an excellent contrast agent for molecular imaging purposes.

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Surfactant-Assisted Synthesis of Water-Soluble and Biocompatible Semiconductor Quantum Dot Micelles

Cited by 238 publications

References 24 publications

Rapid detection of vegetable cooking oils adulterated with inedible used oil using fluorescence quenching method with aqueous CTAB-coated quantum dots

Rapid detection of vegetable cooking oils adulterated with inedible used oil using fluorescence quenching method with aqueous CTAB-coated quantum dots

Fabrication and Size‐Selective Bioseparation of Magnetic Silica Nanospheres with Highly Ordered Periodic Mesostructure

Quantum Dots with a Paramagnetic Coating as a Bimodal Molecular Imaging Probe

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