Chelation Gradients for Investigation of Metal Ion Binding at Silica Surfaces

Kannan, Balamurali; Higgins, Daniel A.; Collinson, Maryanne M.

doi:10.1021/la502088k

Cited by 13 publications

(19 citation statements)

References 46 publications

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“…As shown in Figure D, a Cu 2+ ion can form a complex with four NH 2 groups in two diamine organosilane molecules (e.g., DAMO) and likely all the N atoms on the surface of DAMO SiNPs are coordinated to the Cu 2+ . The coordination of Cu 2+ ion to the surrounding N atoms of DAMO molecules has been observed previously . As a result, the fluorescence of DAMO SiNPs is significantly quenched by Cu 2+ via the interaction between N and Cu.…”

Section: Resultssupporting

confidence: 61%

One‐Step Synthesis of Superbright Water‐Soluble Silicon Nanoparticles with Photoluminescence Quantum Yield Exceeding 80%

Zhang

Kai

et al. 2015

Adv Materials Inter

120

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unique optical properties such as strong luminescence, high photostability, and size-tunable emission wavelength. [ 1 ] However, these semiconductor QDs usually have the problem of low biocompatibility. Thus it is urgent to fi nd alternative fl uorescent nanoparticles with similar optical properties. Silicon, the second most abundant element on earth, is nontoxic (or with low toxicity) and essential for human health. [ 2 ] Because of their superb electronic, optical, and mechanical properties, silicon-based nanostructures (such as nanospheres, nanoribbons, nanowires, nanorods, and nanodots) have been extensively employed in a large variety of applications, including those related to optoelectronics, energy, catalysis, bioanalysis, and biology. [ 3 ] With many superior characteristics including excellent optical properties, easy surface modifi cation capability, superb biocompatibility, and low cytotoxicity, fl uorescent silicon nanoparticles (SiNPs) are being considered as replacements for current fl uorescence labels in biological, biomedical, and biochemical applications, including longterm bioimaging [ 2c,d , 4 ] and sensing. [ 5 ] Numerous methods for preparing free-standing SiNPs have been developed and can be classifi ed into three categories: [ 6 ] (1) the top-down approach using bulk silicon materials (e.g., etching of bulk silicon [ 7 ] and breaking down silicon rich Fluorescent silicon nanoparticles (SiNPs) have shown potential applications in bioimaging/biolabelling, sensing, and nanomedicine/cancer therapy due to their superior properties such as excellent photostability, low cytotoxicity, and versatile surface modifi cation capability. Here, a simple, high-yield, and one-pot method is developed to prepare superbright, water-soluble, and amine-functionalized SiNPs with photoluminescence quantum yield (PLQY) comparable to fl uorescent II-VI semiconductor quantum dots (QDs) but with much lower cytotoxicity. By introducing a commercially available amine-containing silane molecule, N-[3-(trimethoxysilyl)propyl]ethylenediamine (DAMO), water-soluble SiNPs are prepared with PLQY of 82.4% via a microwave-assisted method. To the best of our knowledge, this is the highest PLQY value ever reported for water-soluble fl uorescent SiNPs. The silicon element in our SiNPs is mainly four-valent silicon and thus these SiNPs may also be termed as oxidized silicon nanospheres or silica nanodots. We have also demonstrated the importance of the silane structure (e.g., a suitable amine content) on the photoluminescence property of the prepared SiNPs. As revealed by the time-resolved photoluminescence technique, the highest PLQY value of DAMO SiNPs is correlated with their monoexponential decay with a relatively long fl uorescence lifetime. In addition, the potential use of these SiNPs has also been demonstrated for fl uorescent patterning/printing and ion sensing (including Cu 2+ and Hg 2+).

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Section: Resultssupporting

confidence: 61%

One‐Step Synthesis of Superbright Water‐Soluble Silicon Nanoparticles with Photoluminescence Quantum Yield Exceeding 80%

Zhang

Kai

et al. 2015

Adv Materials Inter

120

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“…Phosphorylated vitamin B 2 (FMN) was labeled to the surface of ZIF‐NPs as a probe with a yield of up to 90% by taking advantage of the high affinity between zinc and phosphate groups . As illustrated in the XPS spectrum, the deconvoluted O 1s peak could be divided into three individuals peaks that could be assigned to O in ZnOP (531.6 eV), POH (532.5 eV), and OCO (533.5 eV) (Figure S2, Supporting Information) . Moreover, broad PO stretching bands between 1100 and 1000 cm −1 appeared in the FT‐IR spectra following the reaction compared with pristine ZIF (Figure S3, Supporting Information) .…”

Section: Resultsmentioning

confidence: 96%

Novel Biological Functions of ZIF‐NP as a Delivery Vehicle: High Pulmonary Accumulation, Favorable Biocompatibility, and Improved Therapeutic Outcome

Wang

Shi

et al. 2016

Adv Funct Materials

138

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Though zeolitic imidazole framework (ZIF) emerges as an advanced functional material for small-molecule delivery due to its unique features such as high loading and pH-sensitive degradation, there are extreme short of knowledge regarding its biological functions. To qualify this category of delivery vehicle, ZIF-8 nanoparticles (ZIF-NPs) with or without cargo are engineered and comprehensively investigated in vitro and in vivo. Interestingly, ZIF-NPs demonstrate strong bioadhesion but with limited internalization themselves, which enhance the membrane-mediated ROS and are different from that of inorganic ZnO inducing mitochondria-mediated reactive oxygen species (ROS) without biomembrane damage. Unexpected high concentration is found in lung, probably due to the particle size and distribution of the nanocarriers; however, the drug levels drop dramatically with time, revealing the fast degradation and elimination. At the given doses, ZIF-NPs exhibit reasonably biosafety in animal tests as evidenced by their acceptable system and blood biocompatibilities, and minimal impacts on the liver and renal functions, immune cells, infl ammatory factors, etc. ZIF-NPs with fl uorouracil loading (5F@ZIF-NPs) signifi cantly improve the therapeutic outcome of lung metastasis tumor in a nude mice model. Generally, ZIF-NPs demonstrate unique biological functions in terms of bio-nano interaction, pulmonary accumulation, biocompatibility, and antitumor therapy, which endow them potential as the delivery vehicles.

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“…The coordination ability of the surface immobilized ligands with the metal ions will be dependent on the number of donor atoms, their orientation on the surface, and their surface density. [33] To more closely examine how the chelator influences separation, gradients were made from three different aminoalkoxysilanes containing one, two, or three donor atoms.…”

Section: Resultsmentioning

confidence: 99%

“…The surface coverage is slightly higher for the materials prepared from amine and is lowest for the triamine, consistent with steric factors as we have noted in prior work. [30,33] The effect of the number of N donor atoms on the separation of the metal ions can be seen in Figure 3, which shows the R f values for the four different metal ions on the different TLC plates prepared with x = 0.08 chelator. What can be immediately seen is that the retention factors depend on the number of donor atoms in the chelator, with greater retention noted on the triamine modified plates.…”

Section: Resultsmentioning

confidence: 99%

Separation of transition and heavy metals using stationary phase gradients and thin layer chromatography

Stegall

Ashraf

Moye

et al. 2016

Journal of Chromatography A

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Stationary phase gradients for chelation thin layer chromatography (TLC) have been investigated as a tool to separate a mixture of metal ions. The gradient stationary phases were prepared using controlled rate infusion (CRI) from precursors containing mono-, bi-, and tri-dentate ligands, specifically 3-aminopropyltriethoxysilane, N-[3-(trimethoxysilyl)propyl] ethylenediamine, and N-[3-(trimethoxysilyl)propyl] diethylenetriamine. The presence and the extent of gradient formation were confirmed using N1s X-ray photoelectron spectroscopy (XPS). XPS results showed that the degree of modification was dependent on the aminosilane precursor, its concentration, and the rate of infusion. The separation of four transition and heavy metals (Co(2+), Pb(2+), Cu(2+), and Fe(3+)) on gradient and uniformly modified plates was compared using a mobile phase containing a stronger chelating agent, ethylenediaminetetraacetic acid (EDTA). The retention of the metal ions was manipulated by varying the surface concentration of the chelating ligands. The order of retention on unmodified plates and on plates modified with a monodentate ligand was Fe(3+)>Cu(2+)∼Pb(2+)∼Co(2+), while the order of retention on plates modified with bi- and tri-dentate ligands was Fe(3+)>Cu(2+)>Pb(2+)∼Co(2+). Fe(3+) and Cu(2+) were much more sensitive to the concentration of chelating ligand on the surface (displaying lower Rf values with increasing ligand concentration) than Pb(2+) and Co(2+). Complete separation was achieved using a high concentration of the tridentate ligand coupled with a longer time for modification, yielding a retention order of Fe(3+)>Cu(2+)>Co(2+)>Pb(2+).

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Chelation Gradients for Investigation of Metal Ion Binding at Silica Surfaces

Cited by 13 publications

References 46 publications

One‐Step Synthesis of Superbright Water‐Soluble Silicon Nanoparticles with Photoluminescence Quantum Yield Exceeding 80%

One‐Step Synthesis of Superbright Water‐Soluble Silicon Nanoparticles with Photoluminescence Quantum Yield Exceeding 80%

Novel Biological Functions of ZIF‐NP as a Delivery Vehicle: High Pulmonary Accumulation, Favorable Biocompatibility, and Improved Therapeutic Outcome

Separation of transition and heavy metals using stationary phase gradients and thin layer chromatography

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