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https://www.readbyqxmd.com/read/28327735/reverse-micelle-based-water-soluble-nanoparticles-for-simultaneous-bioimaging-and-drug-delivery
#1
Ying Chen, Yong Liu, Yongchao Yao, Shiyong Zhang, Zhongwei Gu
With special confined water pools, reverse micelles (RMs) have shown potential for a wide range of applications. However, the inherent water-insolubility of RMs hinders their further application prospects, especially for applications related to biology. We recently reported the first successful transfer of RMs from organic media to an aqueous phase without changing the smart water pools by the hydrolysis of an arm-cleavable interfacial cross-linked reverse micelles. Herein, we employed another elaborate amphiphile 1 to construct new acrylamide-based cross-linked water-soluble nanoparticles (ACW-NPs) under much gentler conditions...
March 22, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28327730/tough-rapid-recovery-composite-hydrogels-fabricated-via-synergistic-core-shell-microgel-covalent-bonding-and-fe-3-coordination-cross-linking
#2
Xuechen Liang, Yukun Deng, Xiaopeng Pei, Kankan Zhai, Kun Xu, Ying Tan, Xinyuan Gong, Pixin Wang
We developed tough, rapid-recovery composite hydrogels that are fabricated via core-shell microgel covalent bonding and Fe(3+) dynamic metal coordination cross-linking. First, core-shell microgels are used as cross-linking agents and initiators to prepare homogeneous hydrogel networks with rapid recovery in the absence of an organic cross-linking agent. The toughness and recoverability of the composite hydrogels can be improved by adding the dynamic reversibility of ionic cross-linking. Owing to the synergistic effect of microgel covalent bonding, Fe(3+) coordination cross-linking, and H-bond cross-linking, the multi-cross-linked composite hydrogels exhibit excellent toughness and a fast recovery rate...
March 22, 2017: Soft Matter
https://www.readbyqxmd.com/read/28325837/threonine-eliminylation-by-bacterial-phosphothreonine-lyases-rapidly-causes-crosslinking-of-mapk-in-live-cells
#3
Benoit M Meijer, Suk Min Jang, Ida C Guerrera, Cerina Chhuon, Joanna Lipecka, Caroline Reisacher, Françoise Baleux, Philippe Sansonetti, Christian Muchardt, Laurence Arbibe
Old long-lived proteins contain dehydroalanine (Dha) and dehydrobutyrine (Dhb), two amino acids engendered by dehydration of serines and threonines respectively. While these residues have a suspected role in protein crosslink and aggregation, their direct implication has yet to be determined. Here, we have taken advantage of the ability of the enteropathogen Shigella to convert the phosphothreonine residue of the pT-X-pY consensus sequence of ERK and p38 into Dhb, and followed the impact of dehydration on the fate of the two MAPKs...
March 21, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28325683/biomimetic-scaffolds-with-three-dimensional-undulated-microtopographies
#4
Jonelle Z Yu, Emrullah Korkmaz, Monica I Berg, Philip R LeDuc, O Burak Ozdoganlar
Many human and animal tissues naturally possess three-dimensional (3D) micro-scale geometries enabling certain physiological functions. Absence of these microgeometries in engineered tissues may undermine the effectiveness of corresponding tissue repair and regeneration. This paper introduces a novel approach to create tissue scaffolds with biomimetic 3D undulated microtopographies. The mechanical micromilling technology is used for precise and reproducible fabrication of poly(methyl methacrylate) (PMMA) master molds with 3D undulated microtopographies...
February 14, 2017: Biomaterials
https://www.readbyqxmd.com/read/28322959/synergistic-effect-of-divalent-cations-in-improving-technological-properties-of-cross-linked-alginate-beads
#5
Andrea Cerciello, Pasquale Del Gaudio, Veronica Granata, Marina Sala, Rita P Aquino, Paola Russo
Gelling solution parameters are some of the most important variables in ionotropic gelation and consequently influence the technological characteristics of the product. To date, only a few studies focused on the simultaneous use of multiple cations as gelling agents. With the aim to deeply explore this possibility, in this research we investigated the effect of two divalent cations (Ca(2+) and Zn(2+)) on alginate beads formation and properties. Alginate beads containing prednisolone (P) as model drug were prepared by prilling technique...
March 16, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28317772/ultrasensitive-detection-of-clenbuterol-by-a-covalent-imprinted-polymer-as-a-biomimetic-antibody
#6
Yiwei Tang, Jingwen Gao, Xiuying Liu, Xue Gao, Tao Ma, Xiaonan Lu, Jianrong Li
As an ideal biomimetic antibody, molecularly imprinted polymer (MIP) has shown great promise in immunoassays. Here, we developed a covalent imprinting method to prepare MIP artificial antibody towards clenbuterol on the well surface of a microtiter plate. Template molecule (clenbuterol) was splited by hydrolysis with functional monomer and removed by methanol/acetic acid solution, and then three-dimensional cavities were fabricated in the MIP, which can rebind template molecule via hydrogen bond interaction...
August 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28317383/design-rules-for-enhanced-interfacial-shear-response-in-functionalized-carbon-fiber-epoxy-composites
#7
Baris Demir, Luke Christian Henderson, Tiffany R Walsh
Carbon-fiber reinforced composites are ideal light-weighting candidates to replace traditional engineering materials. The mechanical performance of these composites results from a complex interplay of influences operating over several length- and time-scales. The mechanical performance may therefore be limited by many factors, one of which being the modest interfacial adhesion between the carbon fiber and the polymer. Surface chemical modification of the fiber, via surface grafting of molecules, is one possible strategy to enhance interactions across the fiber-polymer interface...
March 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28316344/mechanoluminescent-imaging-of-osmotic-stress-induced-damage-in-a-glassy-polymer-network
#8
Jess M Clough, Jasper van der Gucht, Rint P Sijbesma
A chemiluminescent mechanophore, bis(adamantyl-1,2-dioxetane), is used to investigate the covalent bond scission resulting from the sorption of chloroform by glassy poly(methyl methacrylate) (PMMA) networks. Bis(adamantyl)-1,2-dioxetane units incorporated as cross-linkers underwent mechanoluminescent scission, demonstrating that solvent ingress caused covalent bond scission. At higher cross-linking densities, the light emission took the form of hundreds of discrete bursts, widely varying in intensity, with each burst composed of 10(7)-10(9) photons...
March 14, 2017: Macromolecules
https://www.readbyqxmd.com/read/28315300/interaction-of-glyceraldehyde-3-phosphate-dehydrogenase-and-heme-the-relevance-of-its-biological-function
#9
Yi Huang, Pengfei Zhang, Zhen Yang, Peipei Wang, Hailing Li, Zhonghong Gao
GAPDH was speculated to function as a transient trap to reduce the potential toxicity of free heme by a specific and reversible binding with heme. Up to now, there has been lack of studies focused on this effect. In this paper, the efficiency of GAPDH-heme complex on catalyzing protein carbonylation and nitration, the cross-linking of heme to protein formation, and cytotoxicity of GAPDH-heme were studied. It was found that the binding of GAPDH could inhibit H2O2-mediated degradation of heme. Peroxidase activity of GAPDH-heme complex was higher than that of free heme, but significantly lower than that of HSA-heme...
March 14, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28301169/conformational-dynamics-of-cyanocobalamin-and-its-conjugates-with-peptide-nucleic-acids
#10
Tomasz Pieńko, Aleksandra J Wierzba, Monika Wojciechowska, Dorota Gryko, Joanna Trylska
Vitamin B12 also called cobalamin (Cbl) is an important enzymatic co-factor taken up by mammalian and also by many bacterial cells. Peptide nucleic acid (PNA) is a synthetic DNA analogue that has the ability to bind in a complementary manner to natural nucleic acids. Provided that PNA is efficiently delivered to cells, it could act as a steric blocker of functional DNA or RNA and regulate gene expression at the level of transcription or translation. Recently, Cbl has been examined as a transporter of various molecules to cells...
March 16, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28296024/a-moldable-nanocomposite-hydrogel-composed-of-a-mussel-inspired-polymer-and-a-nanosilicate-as-a-fit-to-shape-tissue-sealant
#11
Yuan Liu, Hao Meng, Zichen Qian, Ni Fan, Wonyoung Choi, Feng Zhao, Bruce P Lee
The engineering of bioadhesives to bind and conform to the complex contour of tissue surfaces remains a challenge. We have developed a novel moldable nanocomposite hydrogel by combining dopamine-modified poly(ethylene glycol) and the nanosilicate Laponite, without the use of cytotoxic oxidants. The hydrogel transitioned from a reversibly cross-linked network formed by dopamine-Laponite interfacial interactions to a covalently cross-linked network through the slow autoxidation and cross-linking of catechol moieties...
March 15, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28294278/controlling-adsorption-and-passivation-properties-of-bovine-serum-albumin-on-silica-surfaces-by-ionic-strength-modulation-and-cross-linking
#12
Jae Hyeon Park, Tun Naw Sut, Joshua A Jackman, Abdul Rahim Ferhan, Bo Kyeong Yoon, Nam-Joon Cho
Understanding the physicochemical factors that influence protein adsorption onto solid supports holds wide relevance for fundamental insights into protein structure and function as well as for applications such as surface passivation. Ionic strength is a key parameter that influences protein adsorption, although how its modulation might be utilized to prepare well-coated protein adlayers remains to be explored. Herein, we investigated how ionic strength can be utilized to control the adsorption and passivation properties of bovine serum albumin (BSA) on silica surfaces...
March 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28292179/cross-linking-approaches-to-tuning-the-mechanical-properties-of-peptide-%C3%AF-electron-hydrogels
#13
Wathsala Liyanage, Herdeline Ann M Ardoña, Hai-Quan Mao, John D Tovar
Self-assembling peptides are extensively exploited as bioactive materials in applications such as regenerative medicine and drug delivery despite the fact that their relatively weak noncovalent interactions often render them susceptible to mechanical destruction and solvent erosion. Herein, we describe how covalent cross-linking enhances the mechanical stability of self-assembling π-conjugated peptide hydrogels. We designed short peptide-chromophore-peptide sequences displaying different reactive functional groups that can form cross-links with appropriately modified bifunctional polyethylene glycol (PEG)-based small guest molecules...
March 15, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28289145/irf6-promotes-keratinocyte-differentiation-in-response-to-porphyromonas-gingivalis
#14
Jennifer Huynh, Glen M Scholz, Jiamin Aw, Eric C Reynolds
We recently demonstrated that the expression of the Interferon regulatory factor 6 (IRF6) transcription factor in oral keratinocytes was stimulated by the periodontal pathogen Porphyromonas gingivalis Here, we have established that IRF6 promotes the differentiation of oral keratinocytes in response to P. gingivalis This was evidenced by the IRF6-dependent upregulation of specific markers of keratinocyte terminal differentiation (e.g. Involucrin, IVL; Keratin 13, KRT13), together with additional transcriptional regulators of keratinocyte differentiation, including Grainyhead-like 3 (GRHL3) and Ovo-like zinc finger 1 (OVOL1)...
March 13, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28286038/multi-stimuli-responsive-biohybrid-nanoparticles-with-cross-linked-albumin-coronae-self-assembled-by-a-polymer-protein-biodynamer
#15
Lin Wang, Li Liu, Bingyang Dong, Hanying Zhao, Mingming Zhang, Wenjuan Chen, Yanhang Hong
A thermoresponsive polymer-protein biodynamer was prepared via the bioconjugation of an aliphatic aldehyde-functionalized copolymer to hydrazine-modified bovine serum albumin (BSA) through reversible pyridylhydrazone linkages. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography (SEC) results indicated that the pyridylhydrazone linkages cleaved in an intracellular-mimicking acidic milieu, thus leading to the release of BSA. The dynamic character of the protein biodynamer was demonstrated by exchange reactions with aldehyde-containing molecules...
March 8, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28285197/graphene-oxide-functionalized-long-period-grating-for-ultrasensitive-label-free-immunosensing
#16
Chen Liu, Qi Cai, Baojian Xu, Weidong Zhu, Lin Zhang, Jianlong Zhao, Xianfeng Chen
We explore graphene oxide (GO) nanosheets functionalized dual-peak long period grating (dLPG) based biosensor for ultrasensitive label-free antibody-antigen immunosensing. The GO linking layer provides a remarkable analytical platform for bioaffinity binding interface due to its favorable combination of exceptionally high surface-to-volume ratio and excellent optical and biochemical properties. A new GO deposition technique based on chemical-bonding in conjunction with physical-adsorption was proposed to offer the advantages of a strong bonding between GO and fiber device surface and a homogeneous GO overlay with desirable stability, repeatability and durability...
March 9, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28275726/enhanced-pedot-adhesion-on-solid-substrates-with-electrografted-p-edot-nh2
#17
Liangqi Ouyang, Bin Wei, Chin-Chen Kuo, Sheevangi Pathak, Brendan Farrell, David C Martin
Conjugated polymers, such as poly(3,4-ethylene dioxythiophene) (PEDOT), have emerged as promising materials for interfacing biomedical devices with tissue because of their relatively soft mechanical properties, versatile organic chemistry, and inherent ability to conduct both ions and electrons. However, their limited adhesion to substrates is a concern for in vivo applications. We report an electrografting method to create covalently bonded PEDOT on solid substrates. An amine-functionalized EDOT derivative (2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methanamine (EDOT-NH2), was synthesized and then electrografted onto conducting substrates including platinum, iridium, and indium tin oxide...
March 2017: Science Advances
https://www.readbyqxmd.com/read/28267577/synthetic-toxic-a%C3%AE-1-42-oligomers-can-assemble-in-different-morphologies
#18
Claude Bobo, Stéphane Chaignepain, Sarah Henry, Hélène Vignaud, Alfred Améadan, Christelle Marchal, Enora Prado, James Doutch, Jean-Marie Schmitter, Corinne Nardin, Sophie Lecomte, Christophe Cullin
BACKGROUND: Alzheimer's disease is the most common neurodegenerative disease associated with aggregation of Aβ peptides. Aβ toxicity is mostly related to the capacity of intermediate oligomers to disrupt membrane integrity. We previously expressed Aβ1-42 in a eukaryotic cellular system and selected synthetic variants on their sole toxicity. The most toxic mutant G37C forms stable oligomers. METHODS: Different biophysical methods (Fluorescence spectroscopy, cross-linking, mass spectrometry (MS), Small Angle X-ray Scattering (SAXS), Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), calcein leakage) were used...
March 3, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28267317/nanocomposites-of-c3n4-with-layers-of-mos2-and-nitrogenated-rgo-obtained-by-covalent-cross-linking-synthesis-characterization-and-her-activity
#19
K Pramoda, U Gupta, M Chhetri, A Bandyopadhyay, S K Pati, C N R Rao
Generation of hydrogen by photochemical, electrochemical, and other means is a vital area of research today, and a variety of materials have been explored as catalysts for this purpose. C3N4, MoS2, and nitrogenated RGO (NRGO) are some of the important catalytic materials investigated for the hydrogen evolution reaction (HER) reaction, but the observed catalytic activities are somewhat marginal. Prompted by preliminary reports that covalent cross-linking of 2D materials to generate heteroassemblies or nanocomposites may have beneficial effect on the catalytic activity, we have synthesized nanocomposites wherein C3N4 is covalently bonded to MoS2 or NRGO nanosheets...
March 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28264530/biosensors-based-on-nano-gold-zeolite-modified-ion-selective-field-effect-transistors-for-creatinine-detection
#20
Berna Ozansoy Kasap, Svitlana V Marchenko, Oleksandr O Soldatkin, Sergei V Dzyadevych, Burcu Akata Kurc
The combination of advantages of using zeolites and gold nanoparticles were aimed to be used for the first time to improve the characteristic properties of ion selective field-effect transistor (ISFET)-based creatinine biosensors. The biosensors with covalently cross-linked creatinine deiminase using glutaraldehyde (GA) were used as a control group, and the effect of different types of zeolites on biosensor responses was investigated in detail by using silicalite, zeolite beta (BEA), nano-sized zeolite beta (Nano BEA) and zeolite BEA including gold nanoparticle (BEA-Gold)...
December 2017: Nanoscale Research Letters
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