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ABSTRACT: Amyloid fibril formation is a critical step in Alzheimer's disease (AD) pathogenesis. Inhibition of Aβ aggregation has shown promising against AD and has been used in clinic trials. Here, a novel strategy is reported for the self-assembly of polyoxometalate-peptide (POM@P) hybrid particles as bifunctional Aβ inhibitors. The two-in-one bifunctional POM@P nanoparticles show an enhanced inhibition effect on amyloid aggregation in mice cerebrospinal fluid. Incorporating a clinically used Aβ fibril-staining dye, congo red (CR), into the hybrid colloidal spheres, the nanoparticles can also act as an effective fluorescent probe to monitor the inhibition process of POM@P via CR fluorescence change in real time. It is believed that such flexible organic-inorganic hybrid systems may prompt the design of new multifunctional materials for AD treatment.
Small 05/2013; · 8.35 Impact Factor
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ABSTRACT: Herein, a pH stimuli-responsive vehicle for intracellular drug delivery using CeO2 capped mesoporous silica nanoparticles (MSN) is reported. β-Cyclodextrin-modified CeO2 nanoparticles could cap onto ferrocene-functionalized mesoporous silica through host-guest interactions. After internalization into A549 cells by a lysosomal pathway, the ferrocenyl moieties are oxidized to ferrocenium ions by CeO2 lids, which could trigger the uncapping of the CeO2 and cause the drugs release. Because of the pH-dependent toxicity, the CeO2 here behaves as a multi-purpose entity that not only acts as a lid but also exhibits a synergistic antitumor effect on cancer cells. Meanwhile, the cell protective effect of CeO2 nanoparticles alone is demonstrated, which ensures that the dissolved CeO2 nanoparticles can be non-toxic to normal cells.
Advanced healthcare materials. 04/2013;
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ABSTRACT: A label-free, resettable, and colorimetric logic network has been realized by utilizing thermally regenerable cerium oxide nanoparticles and biocatalytic reactions. Coupling switchable CeO(2) nanoparticles with biocomputing would convert molecular recognition events into colorimetric outputs and make logic gates feasible to reset.
Angewandte Chemie International Edition 11/2012; · 13.45 Impact Factor
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ABSTRACT: A cationic perylene tetracarboxylic acid diimide derivative (1) is employed as a probe for in situ monitoring Aβ aggregation and screening Aβ inhibitors. The assay is based on the fluorescence change through the aggregation of compound 1 following Aβ assembly. Importantly, this probe, compared with the well known amyloid-staining compound Thioflavin T (ThT), is more sensitive to Aβ oligomer, which is highly toxic and plays a crucial role in the early stage of Alzheimer's disease.
Small 09/2012; · 8.35 Impact Factor
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ABSTRACT: A new approach for the visual detection of glucose based on a H(2)O(2) triggered sol-gel transition in combination with modified gold nanoparticles is reported.
Chemical Communications 03/2012; 48(31):3739-41. · 6.17 Impact Factor
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ABSTRACT: Here we report a metal ion sensor with high potassium selectivity and tunable dynamic range by using an ion-selective crown ether and fluorescence resonance energy transfer from carbon dots to graphene.
Chemical Communications 12/2011; 48(9):1284-6. · 6.17 Impact Factor
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ABSTRACT: Spiropyran dye-modified multi-walled carbon nanotubes have been synthesized and used to regulate horseradish peroxidase activity by light irradiation. This design has been developed for a label-free colorimetric assay of lysozyme with a direct detection limit of 30 nM.
Chemical Communications 08/2011; 47(32):9083-5. · 6.17 Impact Factor
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ABSTRACT: Here we report that a cytosine-rich DNA carrier, that oscillates between a hairpin and an i-motif structure in its response to pH variation, can be used as a drug binding and release device.
Chemical Communications 06/2011; 47(28):8043-5. · 6.17 Impact Factor
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ABSTRACT: As a promising strategy for artificially control of gene expression, reversible assembly of nanomaterials and DNA nanomachine, DNA triplex formation has received much attention. Carbon nanotubes as gene and drug delivery vector or as 'building blocks' in nano/microelectronic devices have been successfully explored. Therefore, studies on triplex DNA-based carbon nanotube hybrid materials are important for development of smart nanomaterials and for gene therapy. In this report, a small molecule directed single-walled carbon nanotubes (SWNTs) self-assembly assay has been developed by disproportionation of SWNTs-dT(22)·dA(22) duplex into triplex dT(22)·dA(22)·dT(22) and dA(22) by a triplex formation inducer, coralyne. This has been studied by circular dichroism, light scattering (LS) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), electrophoretic mobility shift assay and supported by using DNA random sequence. In contrast, SWNTs do not aggregate under the same experimental conditions when the small molecules used can not induce dT(22)·dA(22)·dT(22) triplex formation. Therefore, this novel small molecule-directed SWNTs self-assembly assay has also been used for screening of triplex inducers in our studies.
Nucleic Acids Research 02/2011; 39(9):3939-48. · 8.03 Impact Factor
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ABSTRACT: Here we combine click chemistry and carbon nanotube peroxidase-like catalytic colour reaction together to develop a turn-on, highly sensitive and selective copper sensor.
Chemical Communications 09/2010; 46(35):6572-4. · 6.17 Impact Factor
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ABSTRACT: Here we report a reusable DNA single-walled carbon nanotube (SWNT)-based fluorescent sensor for highly sensitive and selective detection of Ag(+) and cysteine (Cys) in aqueous solution. SWNTs can effectively quench the fluorescence of dye-labeled single-stranded DNA due to their strong pi-pi stacking interactions. However, upon incubation with Ag(+), Ag(+) can induce stable duplex formation mediated by C-Ag(+)-C (C=cytosine) coordination chemistry, which has been further confirmed by DNA melting studies. This weakens the interactions between DNA and SWNTs, and thus activates the sensor fluorescence. On the other hand, because Cys is a strong Ag(+) binder, it can remove Ag(+) from C-Ag(+)-C base pairs and deactivates the sensor fluorescence by rewrapping the dye-labeled oligonucleotides around the SWNT. In this way, the fluorescence signal-on and signal-off of a DNA/SWNT sensor can be used to detect aqueous Ag(+) and Cys, respectively. This sensing platform exhibits high sensitivity and selectivity toward Ag(+) and Cys versus other metal ions and the other 19 natural amino acids, with a limit of detection of 1 nM for Ag(+) and 9.5 nM for Cys. Based on these results, we have constructed a reusable fluorescent sensor by using the covalent-linked SWNT-DNA conjugates according to the same sensing mechanism. There is no report on the use of SWNT-DNA assays for the detection of Ag(+) and Cys. This assay is simple, effective, and reusable, and can in principle be used to detect other metal ions by substituting C-C base pairs with other native or artificial bases that selectively bind to other metal ions.
Chemistry 07/2010; 16(27):8147-54. · 5.93 Impact Factor
