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Click chemistry

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https://www.readbyqxmd.com/read/29148805/near-infrared-quantum-dot-emission-enhanced-by-stabilized-self-assembled-j-aggregate-antennas
#1
Francesca S Freyria, José M Cordero, Justin R Caram, Sandra Doria, Amro Dodin, Yue Chen, Adam P Willard, Moungi G Bawendi
Enhancing photoluminescent emission (PL) in the near-infrared-infrared (NIR-IR) spectral region has broad applications from solar energy conversion to biological imaging. We show that self-assembled molecular dye J-aggregates (light-harvesting nanotubes, LHNs) can increase the PL emission of NIR PbS quantum dots (QDs) in both liquid and solid media more than 8-fold, promoted primarily by a long-range antenna effect and efficient Förster resonance energy transfer (FRET) from donor to acceptor. To create this composite material and preserve the optical properties of the nanocrystals, we performed an in situ ligand substitution followed by a functionalization reaction using click-chemistry...
November 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/29147710/step-by-step-build-up-of-covalent-poly-ethylene-oxide-nanogel-films
#2
S Zahouani, L Hurman, M De Giorgi, C Vigier-Carrière, F Boulmedais, B Senger, B Frisch, P Schaaf, P Lavalle, L Jierry
Hydrogels based on poly(ethylene glycol) (PEG) are commonly used for studies related to cell fate and tissue engineering. Here we present a new covalent layer-by-layer build-up process leading to PEG coatings of nanometer size called "nanogel films". Compared to macroscopic hydrogels, such nanogels should provide a fine control over the structure and the thickness of the coating. Alternated deposition of bifunctional and tetra functional PEG molecules reacting through thiol/maleimide click chemistry is evaluated by quartz crystal microbalance...
November 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/29136862/stimulus-response-click-chemistry-based-aptamer-functionalized-mesoporous-silica-nanoparticles-for-fluorescence-detection-of-thrombin
#3
Zhonghui Chen, Mi Sun, Fang Luo, Kefeng Xu, Zhenyu Lin, Lan Zhang
In most aptamer based stimulus response mesoporous silica nanoparticles (MSN) systems, the aptamer is modified on the MSN via electrostatic interaction, however leakage might exist after a certain time in the system and hence the stability is not good. In this study, the pores of MSN were capped by aptamer through click chemistry reaction for the first time and the system was then employed to develop a fluorescence biosensor. Specifically, the aptamer of the target (thrombin in this study) was hybridized with its complementary DNA (which was initially modified with alkyne at the terminal) to form a double strand DNA (dsDNA) firstly, and then this dsDNA was modified on N3 modified MSN via Cu(I) catalyzed alkyne-azide cycloaddition reaction...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136812/silica-based-click-dibenzo-18-crown-6-ether-high-performance-liquid-chromatography-stationary-phase-and-its-application-in-separation-of-fullerenes
#4
Yanzhe Li, Zhe Sheng, Chuanlei Zhu, Wei Yin, Changhu Chu
Crown ether is a type of typical macrocyclic polyether compounds, which can produce strong interactions with cationic species, such as metal ions and protonated amines due to its cavity structure and the strong electronegative effect of heteroatoms on the crown ether ring. In this paper, a type of silica based crown ether stationary phase was prepared by covalently bonding dibenzo-18-crown 6-ether (DBCE) on silica gel via copper (I) catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC). The tetraazido DBCE was rapidly prepared by bromomethylation and subsequent azido substitution of DBCE...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29134076/1-2-aminophenyl-1h-1-2-3-triazole-4-carboxylic-acid-activity-against-gram-positive-and-gram-negative-pathogens-including-vibrio-cholerae
#5
Krishnendu Maji, Debasish Haldar
We report a new synthetic aromatic ε-amino acid containing a triazole moiety with antimicrobial potential against Gram-positive, Gram-negative and pathogenic bacteria including Vibrio cholerae. Structure-property relationship studies revealed that all the functional groups are essential to enhance the antimicrobial activity. The 1-(2-aminophenyl)-1H-1,2,3-triazole-4-carboxylic acid was synthesized by click chemistry. From X-ray crystallography, the amino acid adopts a kink-like structure where the phenyl and triazole rings are perpendicular to each other and the amine and acid groups maintain an angle of 60°...
October 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/29128530/cell-instructive-pectin-hydrogels-crosslinked-via-thiol-norbornene-photo-click-chemistry-for-skin-tissue-engineering
#6
Rúben F Pereira, Cristina C Barrias, Paulo J Bártolo, Pedro L Granja
Cell-instructive hydrogels are attractive for skin repair and regeneration, serving as interactive matrices to promote cell adhesion, cell-driven remodeling and de novo deposition of extracellular matrix components. This paper describes the synthesis and photocrosslinking of cell-instructive pectin hydrogels using cell-degradable peptide crosslinkers and integrin-specific adhesive ligands. Protease-degradable hydrogels obtained by photoinitiated thiol-norbornene click chemistry are rapidly formed in the presence of dermal fibroblasts, exhibit tunable properties and are capable of modulating the behavior of embedded cells, including the cell spreading, hydrogel contraction and secretion of matrix metalloproteases...
November 8, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/29126731/synthesis-antibacterial-properties-and-2d-qsar-studies-of-quinolone-triazole-conjugates
#7
Hassan M Faidallah, Adel S Girgis, Anand D Tiwari, Hitesh H Honkanadavar, Sean J Thomas, Ahmed Samir, Atef Kalmouch, Khalid A Alamry, Khalid A Khan, Tarek S Ibrahim, Amany M M Al-Mahmoudy, Abdullah M Asiri, Siva S Panda
A set of 1,2,3-triazole incorporated quinolone antibiotic conjugates 10-15, 17-19 were synthesized via microwave assisted click chemistry technique. Some of the aryl-substituted conjugates 17-19 show promising antibacterial properties against the tested Gram-positive (S. aureus and S. pyogenes) and Gram-negative bacteria (S. typhi) with potency higher than that of the parent antibiotics 1-3. 2D-QSAR modeling supports the observed biological properties.
October 16, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29125279/molecular-weight-and-charge-density-effects-of-guanidinylated-biodegradable-polycarbonates-on-antimicrobial-activity-and-selectivity
#8
Chloe A Hae Cho, Chao Liang, Janesha Perera, Jie Liu, Kyriakos G Varnava, Vijayalekshmi Sarojini, Ralph P Cooney, Duncan J McGillivray, Margaret A Brimble, Simon Swift, Jianyong Jin
Six guanidine functionalized aliphatic biodegradable polycarbonates with varying molecular weights and charge densities were synthesized via post-synthesis modification of alkyne containing polycarbonates using Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry. The concept of passive diluting group was to modify the cationic charge density of the polycarbonate without changing its hydrophilicity. Within the molecular weight range from 8,000 g mol-1 to 30,000 g mol-1, these guanidine polycarbonates exhibited broad-spectrum biocidal activity with low toxicity to red blood cells (RBCs)...
November 10, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/29122981/in-situ-imaging-of-mitochondrial-translation-shows-weak-correlation-with-nucleoid-dna-intensity-and-no-suppression-during-mitosis
#9
Christopher Estell, Emmanouela Stamatidou, Sarah El-Messeiry, Andrew Hamilton
Although mitochondrial translation produces only 13 proteins, we show here how this can be labelled and detected in situ by fluorescence microscopy with a simple, rapid and inexpensive procedure using non-canonical amino acid labelling and click chemistry. This allows visualisation of the translational output in different mitochondria within a cell, their position within that cell and a comparison of mitochondrial translation between cells. Most highly translationally active mitochondria were closest to the nucleus but were also found at the distal end of long cellular projections...
November 9, 2017: Journal of Cell Science
https://www.readbyqxmd.com/read/29120074/a-fret-sensor-to-monitor-bivalent-sumo-sim-interactions-in-sumo-chain-binding
#10
Lisa J Kost, Henning D Mootz
The small ubiquitin-like modifier (SUMO) can be assembled into polymeric chains as part of its diverse biochemical signal pattern when conjugated to substrate proteins. SUMO chain recognition is facilitated by receptor proteins containing at least two SUMO-interacting motifs (SIMs). Only little is known about the structure of SUMO chains, both in unliganded form and when complexed with multi-SIM protein partners. We have developed a FRET sensor based on a linear dimer of human SUMO-2 as a minimal SUMO chain analog...
November 9, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29112379/high-throughput-chemical-probing-of-full-length-protein-protein-interactions
#11
James M Song, Arya Menon, Dylan C Mitchell, Oleta T Johnson, Amanda L Garner
Human biology is regulated by a complex network of protein-protein interactions (PPIs), and disruption of this network has been implicated in many diseases. However, the targeting of PPIs remains a challenging area for chemical probe and drug discovery. Although many methodologies have been put forth to facilitate these efforts, new technologies are still needed. Current biochemical assays for PPIs are typically limited to motif-domain and domain-domain interactions, and assays that will enable the screening of full-length protein systems, which are more biologically relevant, are sparse...
November 14, 2017: ACS Combinatorial Science
https://www.readbyqxmd.com/read/29111681/design-of-glycopolymers-carrying-sialyl-oligosaccharides-for-controlling-the-interaction-with-the-influenza-virus
#12
Masanori Nagao, Yurina Fujiwara, Teruhiko Matsubara, Yu Hoshino, Toshinori Sato, Yoshiko Miura
We designed glycopolymers carrying sialyl oligosaccharides by "post-click" chemistry and evaluated the interaction with the influenza virus. The glycopolymer structures were synthesized in a well-controlled manner by reversible addition-fragmentation chain transfer polymerization and the Huisgen reaction. Acrylamide-type monomers were copolymerized to give hydrophilicity to the polymer backbones, and the hydrophilicity enabled the successful introduction of the oligosaccharides into the polymer backbones. The glycopolymers with different sugar densities and polymer lengths were designed for the interaction with hemagglutinin on the virus surface...
November 14, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/29109777/improved-tumor-targeting-and-longer-retention-time-of-nir-fluorescent-probes-using-bioorthogonal-chemistry
#13
Xianghan Zhang, Bo Wang, Na Zhao, Zuhong Tian, Yunpeng Dai, Yongzhan Nie, Jie Tian, Zhongliang Wang, Xiaoyuan Chen
The traditional labeling method for targeted NIR fluorescence probes requires directly covalent-bonded conjugation of targeting domains and fluorophores in vitro. Although this strategy works well, it is not sufficient for detecting or treating cancers in vivo, due to steric hindrance effects that relatively large fluorophore molecules exert on the configurations and physiological functions of specific targeting domains. The copper-free, "click-chemistry"-assisted assembly of small molecules in living systems may enhance tumor accumulation of fluorescence probes by improving the binding affinities of the targeting factors...
2017: Theranostics
https://www.readbyqxmd.com/read/29106408/cell-type-specific-metabolic-labeling-of-nascent-proteomes-in-vivo
#14
Beatriz Alvarez-Castelao, Christoph T Schanzenbächer, Cyril Hanus, Caspar Glock, Susanne Tom Dieck, Aline R Dörrbaum, Ina Bartnik, Belquis Nassim-Assir, Elena Ciirdaeva, Anke Mueller, Daniela C Dieterich, David A Tirrell, Julian D Langer, Erin M Schuman
Although advances in protein labeling methods have made it possible to measure the proteome of mixed cell populations, it has not been possible to isolate cell-type-specific proteomes in vivo. This is because the existing methods for metabolic protein labeling in vivo access all cell types. We report the development of a transgenic mouse line where Cre-recombinase-induced expression of a mutant methionyl-tRNA synthetase (L274G) enables the cell-type-specific labeling of nascent proteins with a non-canonical amino-acid and click chemistry...
November 6, 2017: Nature Biotechnology
https://www.readbyqxmd.com/read/29104242/synthesis-and-anti-proliferative-effects-of-mono-and-bis-purinomimetics-targeting-kinases
#15
Andrea Bistrović, Anja Harej, Petra Grbčić, Mirela Sedić, Sandra Kraljević Pavelić, Mario Cetina, Silvana Raić-Malić
A series of mono-pyrrolo[2,3-d]pyrimidines 4a-4k, unsymmetrical bis-purine isosteres 5a-5e and symmetrical bis-pyrrolo[2,3-d]pyrimidines 6a and 6b connected via di(1,2,3-triazolyl)phenyl linker were synthesized by click chemistry. Whereas mono- 4g and bis-pseudopurine 5e showed selective inhibitory activities on cervical carcinoma (HeLa) cells, bis-pyrrolo[2,3-d]pyrimidine 6b exhibited potent and selective anti-proliferative effect in the nanomolar range on pancreatic carcinoma (CFPAC-1) cells. Among these, compound 6b induced a significant reduction in the expression level of CDK9 (cyclin-dependent kinase 9)/cyclin T1 in CFPAC-1 cells concomitant with attenuation of proliferative signaling mediated by c-Raf (rapidly accelerated fibrosarcoma) and p38 MAP (mitogen-activated protein) kinases...
November 1, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29103973/potential-antimicrobial-agents-from-triazole-functionalized-2h-benzo-b-1-4-oxazin-3-4h-ones
#16
Rajitha Bollu, Saleha Banu, Rajashaker Bantu, A Gopi Reddy, Lingaiah Nagarapu, K Sirisha, C Ganesh Kumar, Shravan Kumar Gunda, Kamal Shaik
A series of substituted triazole functionalized 2H-benzo[b][1,4]oxazin-3(4H)-ones were synthesized by employing click chemistry and further characterized based on (1)H NMR, (13)C NMR, IR and mass spectral studies. All the synthesized derivatives were screened for their in vitro antimicrobial activities. Further, molecular docking studies were accomplished to explore the binding interactions between 1,2,3-triazol-4-yl-2H-benzo[b][1,4]oxazin-3(4H)-one and the active site of Staphylococcus aureus (CrtM) dehydrosqualene synthase (PDB ID: 2ZCS)...
October 28, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/29098191/detecting-the-interaction-of-peptide-ligands-with-plant-membrane-receptors
#17
Sarah Refi Hind, Jason S Hoki, Joshua A Baccile, Patrick C Boyle, Frank C Schroeder, Gregory B Martin
The field of plant receptor biology has rapidly expanded in recent years, however the demonstration of direct interaction between receptor-ligand pairs remains a challenge. Click chemistry has revolutionized small molecule research but lacks popularity in plant research. Here we describe a method that tests for the direct physical interaction of a candidate receptor protein and a peptide ligand. This protocol describes the generation of the ligand probe, transient expression of a receptor protein, enrichment of membrane-bound receptors, photo-crosslinking and click chemistry-mediated reporter addition, and detection of the receptor-ligand complex...
September 2017: Current Protocols in Plant Biology
https://www.readbyqxmd.com/read/29096103/tuning-the-position-of-head-groups-by-surfactant-design-in-mixed-micelles-of-cationic-and-carbohydrate-surfactants
#18
Saikat Das, Edward Davis Oldham, Hans-Joachim Lehmler, Barbara L Knutson, Stephen E Rankin
HYPOTHESIS: Emerging applications of carbohydrate/cationic surfactant mixtures require not only synergistic mixing, but also accessible sugar headgroups at the exterior of micelles. A previous study showed that the glucoside headgroups of octyl-β-d-glucopyranoside aggregate at the interior of mixed micelles with equimolar cetyltrimethylammonium bromide rather than mixing with trimethylammonium groups at the corona. The current study tests the hypothesis that structural characteristics of the surfactants (the relative lengths of the alkyl tails and the type of linker) can be tuned to shift the carbohydrate groups to micelle surfaces...
October 18, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29095606/ex-uno-plura-differential-labeling-of-phospholipid-biosynthetic-pathways-with-a-single-bioorthogonal-alcohol
#19
Timothy W Bumpus, Felice J Liang, Jeremy M Baskin
Imaging approaches that track biological molecules within cells are essential tools in modern biochemistry. Lipids are particularly challenging to visualize, as they are not directly genetically encoded. Phospholipids, the most abundant subgroup of lipids, are structurally diverse and accomplish many cellular functions, acting as major structural components of membranes and as signaling molecules that regulate cell growth, division, apoptosis, cytoskeletal dynamics, and numerous other physiological processes...
November 8, 2017: Biochemistry
https://www.readbyqxmd.com/read/29094794/preparation-of-highly-hydrophilic-magnetic-nanoparticles-with-anion-exchange-ability-and-their-application-for-the-extraction-of-nonsteroidal-anti-inflammatory-drugs-in-environmental-samples
#20
Li-Yun Ma, Qian Li, Jing Li, Li Xu
Diallyldimethylammonium chloride modified magnetic nanoparticles were synthesized by the "thiol-ene" click chemistry reaction. Diallyldimethylammonium chloride rendered the material plenty of quaternary ammonium groups, and thus the excellent aqueous dispersibility and anion-exchange capability. The novel material was then used as the magnetic solid-phase extraction sorbent to extract eight non-steroidal anti-inflammatory drugs from water samples. Combined with high-performance liquid chromatography and ultraviolet detection, under the optimal conditions, the developed method exhibited wide linearity ranges (1-1000, 2-1000 and 5-1000 ng mL(-1) ) with recoveries of 88...
November 2, 2017: Journal of Separation Science
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