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Exchange of Methyl‐ and Azobenzene‐Terminated Alkanethiols on Polycrystalline Gold Studied by Tip‐Enhanced Raman Mapping 下载免费PDF全文
Dr. Gennaro Picardi Dr. Agata Królikowska Dr. Ryohei Yasukuni Dr. Marc Chaigneau Dr. Marie Escude Dr. Véronique Mourier Dr. Christophe Licitra Prof. Razvigor Ossikovski 《Chemphyschem》2014,15(2):276-282
Mixed thiol self‐assembled monolayers (SAMs) presenting methyl and azobenzene head groups were prepared by chemical substitution from the original single‐component n‐decanethiol or [4‐(phenylazo)phenoxy]hexane‐1‐thiol SAMs on polycrystalline gold substrates. Static contact‐angle measurements were carried out to confirm a change in the hydrophobicity of the functionalized surfaces following the exchange reaction. The mixed SAMs presented contact‐angle values between those of the more hydrophobic n‐decanethiol and the more hydrophilic [4‐(phenylazo)phenoxy]hexane‐1‐thiol single‐component SAMs. By means of tip‐enhanced Raman spectroscopy (TERS) mapping experiments, it was possible to highlight that molecular replacement takes place easily and first at grain boundaries: for two different mixed SAM compositions, TERS point‐by‐point maps with <50 nm step sizes showed different spectral signatures in correspondence to the grain boundaries. An example of the substitution extending beyond grain boundaries and affecting flat areas of the gold surface is also shown. 相似文献
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《Macromolecular bioscience》2017,17(4)
Early and accurate detection of hepatocellular carcinoma (HCC) is essential to improve the prognosis of patients and reduce the morbidity of surgical therapy. Glypican‐3 (GPC3) is a protein abnormally expressed in HCC that has been identified as a serological and histochemical HCC marker. A novel peptide that specifically recognizes GPC3 will facilitate early detection of HCC and guide the treatment strategy. Herein, phage display screening technology is utilized to obtain a GPC3 binding peptide (GBP) using HCC cells expressing GPC3 in varying abundances. After seven rounds of panning, a peptide with sequence of THVSPNQGGLPS is identified with 735.2 ± 53.6 × 10−9 m affinity to GPC3. The ability to target GPC3 in vivo is evaluated by intravenous injection of GBP labeled with a near‐infrared dye, Cy5.5, into a HCC tumor‐bearing mouse model. Significant high tumor accumulation (tumor/muscle ratio: 6.49 ± 0.55) of Cy5.5‐GBP in HepG2 tumors is observed compared with that of the low GPC3 expressing prostate cancer cell line, PC3 (tumor/muscle ratio: 1.15 ± 0.32). By targeting GPC3, GBP differentiates tumor tissues from normal liver tissues in patients, suggesting a great clinical translation potency of GBP. Collectively, GBP demonstrates great potential for HCC detection via fluorescent imaging or histological staining.
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Xiaoshan Shayna Wang Peng‐Hsun Chase Chen J. Trae Hampton Jeffery M. Tharp Catrina A. Reed Sukant K. Das Duen‐Shian Wang Hamed S. Hayatshahi Yang Shen Jin Liu Wenshe Ray Liu 《Angewandte Chemie (International ed. in English)》2019,58(44):15904-15909
Superior to linear peptides in biological activities, cyclic peptides are considered to have great potential as therapeutic agents. To identify cyclic‐peptide ligands for therapeutic targets, phage‐displayed peptide libraries in which cyclization is achieved by the covalent conjugation of cysteines have been widely used. To resolve drawbacks related to cysteine conjugation, we have invented a phage‐display technique in which its displayed peptides are cyclized through a proximity‐driven Michael addition reaction between a cysteine and an amber‐codon‐encoded N?‐acryloyl‐lysine (AcrK). Using a randomized 6‐mer library in which peptides were cyclized at two ends through a cysteine–AcrK linker, we demonstrated the successful selection of potent ligands for TEV protease and HDAC8. All selected cyclic peptide ligands showed 4‐ to 6‐fold stronger affinity to their protein targets than their linear counterparts. We believe this approach will find broad applications in drug discovery. 相似文献
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Amphiphilic polymer brushes grafted onto gold nanoparticles impart distinct solvent‐responsive behavior via the change to particle size and surface chemistry and, therefore, wide application prospects can be expected. Coarse‐grained simulations are performed for block and/or mixed polystyrene (PS)/poly(ethylene oxide) (PEO)‐modified amphiphilic gold nanoparticles (AuNP) to investigate their responsive behavior in five different solvents by analyzing their morphology, distribution density profiles, and gyration radii. Typical core–shell, Janus‐type, buckle‐like, ring‐like, jellyfish‐like, and octopus‐like morphologies are formed. Influence of block sequence, mixing mode, and several other effects are discussed. Responsive particle size and surface hydrophilicity can be successfully reproduced by altering solvents.
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Radosaw W. Piast Rafa M. Wieczorek Nicola Marzec Maciej Garstka Aleksandra Misicka 《Molecules (Basel, Switzerland)》2021,26(19)
Chondrocalcinosis is a metabolic disease caused by the presence of calcium pyrophosphate dihydrate crystals in the synovial fluid. The goal of our endeavor was to find out whether short peptides could be used as a dissolving factor for such crystals. In order to identify peptides able to dissolve crystals of calcium pyrophosphate, we screened through a random library of peptides using a phage display. The first screening was designed to select phages able to bind the acidic part of alendronic acid (pyrophosphate analog). The second was a catalytic assay in the presence of crystals. The best-performing peptides were subsequently chemically synthesized and rechecked for catalytic properties. One peptide, named R25, turned out to possess some hydrolytic activity toward crystals. Its catalysis is Mg2+-dependent and also works against soluble species of pyrophosphate. 相似文献
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Nurxat Nuraje Dr. Samia Mohammed Linglu Yang Dr. Hiroshi Matsui Prof. 《Angewandte Chemie (International ed. in English)》2009,48(14):2546-2548
From top to bottom : Peptide lines were formed in trenches in the self‐assembled monolayer (SAM) on an Au substrate. Combination of the top‐down (peptide nanolithography) and the bottom‐up fabrications (biomineralization) yielded arrays of monodisperse Au nanoparticles assembled on the peptide lines (see picture). The number of nanoparticles on the lines was simply determined by the width of the peptide pattern.
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Dr. Jianxiu Du Yadi Wang Weimin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(27):8540-8546
A label‐free, non‐derivatization chemiluminescence resonance energy transfer (CRET) detection platform has been developed for the detection of the non‐fluorescent small molecule 6‐mercaptopurine. This CRET process arose from a chemiluminescent (CL) donor–acceptor system in which the reaction of bis(2,4,6‐trichlorophenyl)oxalate (TCPO)–H2O2–fluorescein (maximum emission at 521.6 nm) served as the donor and gold nanoparticles (AuNPs, maximum absorption at 520.0 nm) served as the acceptor. This process caused a significant decrease in the CL signal of the TCPO–H2O2–fluorescein reaction. The presence of 6‐mercaptopurine induced an aggregation of AuNPs with the assistance of Cu2+ ions through cooperative metal–ligand interactions that was accompanied by a distinct change in color and optical properties. The maximum absorption band of the AuNPs was red‐shifted to 721.0 nm and no longer overlapped with the CL spectrum of the reaction; as a result, the CL signal was restored. This CRET system exhibited a wide linear range, from 9.0 nmol L?1 to 18.0 μmol L?1, and a low detection limit (0.62 nmol L?1) for 6‐mercaptopurine. The applicability of the proposed CRET system was evaluated by analysis of 6‐mercaptopurine in spiked human plasma samples. 相似文献
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Joon Suk Oh Luong Nguyen Dang Sung Woon Yoon Pyoung Chan Lee Dong Ouk Kim Kwang Jin Kim Jae Do Nam 《Macromolecular rapid communications》2013,34(6):504-510
Polyglycidyl methacrylate (PGMA) microspheres, crosslinked and surface‐functionalized by amine, can be used as a solid‐state template for the synthesis of gold (Au) crystals in the forms of either nanoparticles (NPs) or plates. It is discovered that the polymer microsphere acts as an internal template to cultivate Au NPs inside the microsphere or an external template to generate the single‐crystal plates depending on the critical concentration (Ccr) of gold ions. The ion–dipole interaction and the structure‐dependent solubility of gold induce two distinct gold nanostructures in the presence of the functionalized polymer microspheres. The catalytic activity and long‐term storage of the developed gold nanostructures that can be easily scaled‐up for mass production through the developed novel methodology is demonstrated. 相似文献
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Sheng Wang Prof. Dr. Wei Chen Prof. Dr. Ai‐Lin Liu Lei Hong Hao‐Hua Deng Prof. Xin‐Hua Lin 《Chemphyschem》2012,13(5):1199-1204
The origin of the peroxidase‐like activity of gold nanoparticles and the impact of surface modification are studied. Furthermore, some influencing factors, such as fabrication process, redox property of the modifier, and charge property of the substrate, are investigated. Compared to amino‐modified or citrate‐capped gold nanoparticles, unmodified gold nanoparticles show significantly higher catalytic activity toward peroxidase substrates, that is, the superficial gold atoms are a contributing factor to the observed peroxidase‐like activity. The different catalytic activities of amino‐modified and citrate‐capped gold nanoparticles toward 3,3′,5,5′‐tetramethylbenzidine (TMB) and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt (ABTS) show that the charge characteristics of the nanoparticles and the substrate also play an important role in the catalytic reactions. 相似文献
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Dorian J. Mikolajczak Allison A. Berger Beate Koksch 《Angewandte Chemie (International ed. in English)》2020,59(23):8776-8785
The self‐assembly of peptides onto the surface of gold nanoparticles has emerged as a promising strategy towards the creation of artificial enzymes. The resulting high local peptide density surrounding the nanoparticle leads to cooperative and synergistic effects, which result in rate accelerations and distinct catalytic properties compared to the unconjugated peptide. This Minireview summarizes contributions to and progress made in the field of catalytically active peptide–gold nanoparticle conjugates. The origin of distinct properties, as well as potential applications, are also discussed. 相似文献
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Reversible Modulation of Surface Plasmons in Gold Nanoparticles Enabled by Surface Redox Chemistry 下载免费PDF全文
Dr. Zheng Li Dr. Jonathan J. Foley IV Dr. Sheng Peng Dr. Cheng‐Jun Sun Dr. Yang Ren Dr. Gary P. Wiederrecht Dr. Stephen K. Gray Dr. Yugang Sun 《Angewandte Chemie (International ed. in English)》2015,54(31):8948-8951
Switchable surface redox chemistry is demonstrated in gold@iron/iron oxide core–shell nanoparticles with ambient oxidation and plasmon‐mediated reduction to modulate the oxidation state of shell layers. The iron shell can be oxidized to iron oxide through ambient oxidation, leading to an enhancement and red‐shift of the gold surface plasmon resonance (SPR). This enhanced gold SPR can drive reduction of the iron oxide shell under broadband illumination to reversibly blue‐shift and significantly dampen gold SPR absorption. The observed phenomena provide a unique mechanism for controlling the plasmonic properties and surface chemistry of small metal nanoparticles. 相似文献
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Chunhua Luo Fang Zuo Zhaohui Zheng Xu Cheng Xiaobin Ding Yuxing Peng 《Macromolecular rapid communications》2008,29(2):149-154
Thermosensitive poly(N‐isopropylacrylamide) (PNIPAm)‐coated gold nanoparticles (AuNPs) were prepared by self‐assembly of the azobenzene‐terminated PNIPAm on the surface of the α‐cyclodextrin (α‐CD)‐capped AuNPs via the host–guest molecular recognition between α‐CD and azobenzene. Reversible attachment–detachment of azobenzene‐terminated PNIPAm on the surface of α‐CD‐capped AuNPs was achieved when subjected to visible and UV light irradiation alternately, which endowed thermosensitive AuNPs with tunable smart properties.
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Toshiki Sawada Hisakazu Mihara Takeshi Serizawa 《Chemical record (New York, N.Y.)》2013,13(2):172-186
Biomolecules express exquisite properties that are required for molecular recognition and self‐assembly on the nanoscale. These smart capabilities have developed through evolution and such biomolecules operate based on smart functions in natural systems. Recently, these remarkable smart capabilities have been utilized in not only biologically related fields, but also in materials science and engineering. A peptide‐screening technology that uses phage‐display systems has been developed based on this natural smart evolution for the generation of new functional peptide bionanomaterials. We focused on peptides that specifically bound to synthetic polymers. These polymer‐binding peptides were screened by using a phage‐display peptide library to recognize nanostructures that were derived from polymeric structural features and were utilized for possible applications as new bionanomaterials. We also focused on self‐assembling peptides with β‐sheet structures that formed nanoscale, fibrous structures for applications in new bottom‐up nanomaterials. Moreover, nanofiber‐binding peptides were also screened to introduce the desired functionalities into nanofibers without the need for additional molecular design. Our approach to construct new bionanomaterials that employ peptides will open up excellent opportunities for the next generation of materials science and technology. 相似文献
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Dr. Nan Gao Hanjun Sun Kai Dong Prof. Jinsong Ren Prof. Xiaogang Qu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(2):829-835
Targeting amyloid‐β (Aβ)‐induced complex neurotoxicity has received considerable attention in the therapeutic and preventive treatment of Alzheimer’s disease (AD). The complex pathogenesis of AD suggests that it requires comprehensive treatment, and drugs with multiple functions against AD are more desirable. Herein, AuNPs@POMD‐pep (AuNPs: gold nanoparticles, POMD: polyoxometalate with Wells–Dawson structure, pep: peptide) were designed as a novel multifunctional Aβ inhibitor. AuNPs@POMD‐pep shows synergistic effects in inhibiting Aβ aggregation, dissociating Aβ fibrils and decreasing Aβ‐mediated peroxidase activity and Aβ‐induced cytotoxicity. By taking advantage of AuNPs as vehicles that can cross the blood–brain barrier (BBB), AuNPs@POMD‐pep can cross the BBB and thus overcome the drawbacks of small‐molecule anti‐AD drugs. Thus, this work provides new insights into the design and synthesis of inorganic nanoparticles as multifunctional therapeutic agents for treatment of AD. 相似文献
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Yudan Ma Yi Guo Jun Li Dr. Jian Guan Li Xu Prof. Wensheng Yang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(47):13135-13140
Single‐strand oligo‐DNA‐modified Au nanoparticles (AuNPs) undergo aggregation in the presence of poly(L ‐lysine) (PLL), which is attributed to the interactions between the oligo‐DNA and PLL. These interactions between the oligo‐DNA and PLL were identified to be electrostatic when the lysine residues of PLL were positively charged and to be hydrogen bonding when the residues were deprotonated. The aggregation was promoted with an increase in the pH value at a pH level lower than the pKa value of PLL (pKa≈10.0) due to the gradual deprotonation of the lysine residues and thus suppressed electrostatic interactions between the positively charged lysine residues of PLL and the negatively charged backbone phosphate groups of the oligo‐DNA. At pH levels higher than the pKa value of PLL, the aggregation was identified to be dominated by the hydrogen bonds between the bases of the oligo‐DNA and the deprotonated lysine residues of PLL. This study prompts the possibility that the spectral, and thus color, change of AuNPs upon aggregation can be used as a probe to follow the interactions between oligo‐DNA and polypeptides. 相似文献
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