Read by QxMD icon Read


Hwankyu Lee
Polyelectrolyte bilayers, which consist of poly-l-lysine (PLL) and hyaluronic acid (HA) were simulated with lipid membranes at different temperatures and ion concentrations. Starting with the sequential deposition of PLL and HA above the membrane surface, PLL and HA become completely mixed, leading to the formation of stable bilayers. PLL/HA bilayers are thicker at higher salt concentration because of weakened electrostatic interactions between PLLs and membrane lipids, in agreement with experiments. This salt effect decreases as PLL size increases...
September 23, 2016: Journal of Molecular Graphics & Modelling
Shunjie Yan, Lingjie Song, Shifang Luan, Zhirong Xin, Shanshan Du, Hengchong Shi, Shuaishuai Yuan, Yuming Yang, Jinghua Yin
Bacterial infections are problematic in many healthcare-associated devices. Antibacterial surfaces integrating the strength of bacteria repellent and bactericidal functions exhibit an encouraging efficacy in tackling this problem. Herein, a hierarchical dual-function antibacterial polymer brush coating that integrates an antifouling bottom layer with a bactericidal top layer is facilely constructed via living photograft polymerization. Excellent resistance to bacterial attachment is correlated with the antifouling components, and good bactericidal activity is afforded by the bactericidal components, and therefore the hierarchical coating shows an excellent long-term antibacterial capability...
August 12, 2016: Colloids and Surfaces. B, Biointerfaces
Nancy M Lee, Cevat Erisken, Thomas Iskratsch, Michael Sheetz, William N Levine, Helen H Lu
Physiologically relevant models of wound healing are essential for understanding the biology of connective tissue repair and healing. They can also be used to identify key cellular processes and matrix characteristics critical for the design of soft tissue grafts. Modeling the various stages of repair post tendon injury, polymer meshes of varying fiber diameter (nano-1 (390 nm) < nano-2 (740 nm) < micro (1420 nm)) were produced. Alignment was also introduced in the nano-2 group to model matrix undergoing biological healing rather than scar formation...
October 12, 2016: Biomaterials
Ross D Milton
Electrochemically-active polymers (redox polymers) are useful tools for simultaneous immobilization and electron transfer of enzymes at electrode surfaces, which also serve to increase the localized concentration of the biocatalyst. The properties of the employed redox couple must be compatible with the target biocatalyst from both an electrochemical (potential) and biochemical standpoint. This chapter details the synthesis of a naphthoquinone-functionalized redox polymer (NQ-LPEI) that is used to immobilize and electronically communicate with flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH), yielding an enzymatic bioanode that is able to deliver large catalytic current densities for glucose oxidation at a relatively low associated potential...
2017: Methods in Molecular Biology
David P Hickey
Enzymatic glucose biosensors and biofuel cells make use of the electrochemical transduction between an oxidoreductase enzyme, such as glucose oxidase (GOx), and an electrode to either quantify the amount of glucose in a solution or generate electrical energy. However, many enzymes including GOx are not able to electrochemically interact with an electrode surface directly, but require an external electrochemical relay to shuttle electrons to the electrode. Ferrocene-modified linear poly(ethylenimine) (Fc-LPEI) redox polymers have been designed to simultaneously immobilize glucose oxidase (GOx) at an electrode and mediate electron transfer from their flavin adenine dinucleotide (FAD) active site to the electrode surface...
2017: Methods in Molecular Biology
Gaige R VandeZande, Jasmine M Olvany, Julia L Rutherford, Michelle Rasmussen
Enzymatic electrodes are becoming increasingly common for energy production and sensing applications. Research over the past several decades has addressed a major issue that can occur when using these biocatalysts, i.e., slow heterogeneous electron transfer, by incorporation of a redox active species to act as an electron shuttle. There are several advantages to immobilizing both the enzyme and mediator at the enzyme surface, including increased electron transfer rates, decreased enzyme leaching, and minimized diffusion limitations...
2017: Methods in Molecular Biology
Sabina Besic, Shelley D Minteer
Although enzymes are highly efficient and selective catalysts, there have been problems incorporating them into fuel cells. Early enzyme-based fuel cells contained enzymes in solution rather than immobilized on the electrode surface. One problem utilizing an enzyme in solution is an issue of transport associated with long diffusion lengths between the site of bioelectrocatalysis and the electrode. This issue drastically decreases the theoretical overall power output due to the poor electron conductivity. On the other hand, enzymes immobilized at the electrode surface have eliminated the issue of poor electron conduction due to close proximity of electron transfer between electrode and the biocatalyst...
2017: Methods in Molecular Biology
Zorica D Knežević-Jugović, Sanja Ž Grbavčić, Jelena R Jovanović, Andrea B Stefanović, Dejan I Bezbradica, Dušan Ž Mijin, Mirjana G Antov
A selection of best combination of adequate immobilization support and efficient immobilization method is still a key requirement for successful application of immobilized enzymes on an industrial level. Eupergit(®) supports exhibit good mechanical and chemical properties and allow establishment of satisfactory hydrodynamic regime in enzyme reactors. This is advantageous for their wide application in enzyme immobilization after finding the most favorable immobilization method. Methods for enzyme immobilization that have been previously reported as efficient considering the obtained activity of immobilized enzyme are presented: direct binding to polymers via their epoxy groups, binding to polymers via a spacer made from ethylene diamine/glutaraldehyde, and coupling the periodate-oxidized sugar moieties of the enzymes to the polymer beads...
2017: Methods in Molecular Biology
Pan Dan, Émilie Velot, Grégory Francius, Patrick Menu, Véronique Decot
: One of the outstanding goals in tissue engineering is to develop a natural coating surface which is easy to manipulate, effective for cell adhesion and fully biocompatible. The ideal surface would be derived from human tissue, perfectly controllable, and pathogen-free, thereby satisfying all of the standards of the health authorities. This paper reports an innovative approach to coating surfaces using a natural extracellular matrix (ECM) extracted from the Wharton's jelly (WJ) of the umbilical cord (referred to as WJ-ECM)...
October 18, 2016: Acta Biomaterialia
Adenike Okunlola, Amusa Sarafadeen Adebayo, Moji Christianah Adeyeye
Tropical starches from Dioscorea dumetorum (bitter) and Dioscorea oppositifolia (Chinese) yams were acetylated with acetic anhydride in pyridine medium and utilized as polymers for the delivery of repaglinide in microsphere formulations in comparison to ethyl cellulose. Acetylated starches of bitter and Chinese yams with degrees of substitution of 2.56 and 2.70 respectively were obtained. Acetylation was confirmed by FTIR, (1)H NMR spectroscopy. A 3(2) factorial experimental design was performed using polymer type and drug-polymer ratio as independent variables...
October 18, 2016: International Journal of Biological Macromolecules
Rakesh Deshar, Eun-Bee Cho, Sungjoo Kim Yoon, Jong-Bok Yoon
Signaling through many transmembrane receptors is terminated by their sorting to the intraluminal vesicles (ILVs) of multivescular bodies (MVBs) and subsequent lysosomal degradation. ILV formation requires the endosomal sorting complex required for transport (ESCRT) machinery. CC2D1A and CC2D1B interact with the CHMP4 family of proteins, the major subunit of the ESCRT-III complex, however, their roles in receptor degradation and signaling are poorly defined. Here, we report that CC2D1A binds to CHMP4B polymers formed on endosomes to regulate the endosomal sorting pathway...
October 18, 2016: Biochemical and Biophysical Research Communications
Siti Baidurah, Paramasivam Murugan, Lee Joyyi, Junya Fukuda, Masaya Yamada, Kumar Sudesh, Yasuyuki Ishida
Thermally assisted hydrolysis and methylation-gas chromatography (THM-GC) in the presence of an organic alkali was validated for the compositional analysis of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] accumulated in whole bacterial cells. Recombinant Cupriavidus necator Re2058/pCB113 was grown in a batch fermentation with different concentration of palm oil and fructose in order to control the molar fraction of 3HHx in P(3HB-co-3HHx) produced in the cells. Trace amounts (30μg) of freeze-dried cells were directly subjected to THM-GC in the presence of tetramethylammonium hydroxide (TMAH) at 400°C...
October 14, 2016: Journal of Chromatography. A
Dongping Yu, Zhimou Guo, Aijin Shen, Jingyu Yan, Xuefang Dong, Gaowa Jin, Zhen Long, Lina Liang, Xinmiao Liang
Zwitterionic polymer stationary phases have attracted increasing attention in hydrophilic interaction chromatography (HILIC). In this work, a zwitterionic sulfobetaine functionalized polyacrylamide stationary phase (named TENS) based on porous silica particles was prepared via controlled surface initiated reversible addition-fragmentation transfer (RAFT) polymerization. Instead of traditional methacrylate type sulfobetaine monomer, acrylamide type sulfobetaine monomer, which has higher chemical stability and hydrophicility, was employed in this work...
December 1, 2016: Talanta
Qiaohui Luo, Neng Yu, Chunfei Shi, Xiaoping Wang, Jianmin Wu
A surface plasmon resonance (SPR) sensor combined with nanoscale molecularly imprinted polymer (MIP) film as recognition element was developed for selective detection of the antibiotic ciprofloxacin (CIP). The MIP film on SPR sensor chip was prepared by in situ photo-initiated polymerization method which has the advantages of short polymerization time, controllable thickness and good uniformity. The surface wettability and thickness of MIP film on SPR sensor chip were characterized by static contact angle measurement and stylus profiler...
December 1, 2016: Talanta
Vladimir V Apyari, Viktoria V Arkhipova, Maria V Gorbunova, Pavel A Volkov, Andrey I Isachenko, Stanislava G Dmitrienko, Yury A Zolotov
In this paper, we report on a novel type of nanocomposites based on gold nanoparticles (AuNPs) and polyurethane foam (PUF), which represents an ability of AuNP aggregation on solid polymer matrix with the strongly different selectivity in comparison with aggregation of the same AuNPs in solution. This may indicate that a new type of aggregation takes place, which can be called solid-phase aggregation. A systematic study using diffuse reflectance spectroscopy revealed features of the solid-phase aggregation...
December 1, 2016: Talanta
Qin Wang, Hongjun Chen, Yong Li, Huixia Wang, Zhou Nie, Yufang Hu, Shouzhou Yao
We report here a label-free and sensitive electrochemical method for probing Citrate synthase (CS) activity based on detailed investigations into the nucleic acid-mimicking coordination polymer (CP) formed from the coenzyme A (CoA)-Ag(I) repeat units. Our biosensing approach provides an especial and significant detection mechanism: CS can catalyze the essential condensation reaction between acetyl-coenzyme A (Ac-CoA) and oxaloacetate (OAA) to form citrate and CoA; then, in the presence of Ag(I), CoA-Ag(I) CP can be in situ formed because of the strong complexation ability of thiol groups of CoA toward Ag(I)...
December 1, 2016: Talanta
Manel Moussa, Valérie Pichon, Clarisse Mariet, Thomas Vercouter, Nathalie Delaunay
Ion imprinted polymers (IIPs) specific to lanthanides were synthesized using neodymium ions (Nd(3+)) as template ions. Nd(3+) ions form binary complex ions with 5,7-dichloroquinoline-8-ol (DCQ) or vinylpyridine (VP), or ternary complex ions with both DCQ and VP in 2-methoxyethanol, before copolymerization in the presence of styrene and divinylbenzene as monomer and cross-linker, respectively. DCQ was expected to be trapped in the synthesized polymers pores. The template ion removal was then optimized. For the first time, the DCQ leakage was determined by HPLC-UV during the template removal and the sedimentation steps before solid-phase extraction (SPE) packing...
December 1, 2016: Talanta
Jamshed Ali, Mustafa Tuzen, Tasneem G Kazi, Baki Hazer
The polymer, polystyrene polydimethyl siloxane was loaded into the micropipette tip of the syringe system as an adsorbent to developed miniaturized solid phase microextraction. Standard solutions of arsenate and arsenite were passed through the adsorbent loaded in micropipette tip to check the adsorption behaviors. It was observed that arsenate adsorbed on the polystyrene polydimethyl siloxane in the pH rang of 6-8, while arsenite was directly passed through the micropipette tip of syringe system. The adsorbed arsenate in micropipette tip of syringe system were eluted by 1...
December 1, 2016: Talanta
Shima N N S Hashim, Lachlan J Schwarz, Basil Danylec, Mahesh K Potdar, Reinhard I Boysen, Milton T W Hearn
This investigation describes a general procedure for the selectivity mapping of molecularly imprinted polymers, using (E)-resveratrol-imprinted polymers as the exemplar, and polyphenolic compounds present in Pinot noir grape skin extracts as the test compounds. The procedure is based on the analysis of samples generated before and after solid-phase extraction of (E)-resveratrol and other polyphenols contained within the Pinot noir grape skins using (E)-resveratrol-imprinted polymers. Capillary reversed-phase high-performance liquid chromatography (RP-HPLC) and electrospray ionisation tandem mass spectrometry (ESI MS/MS) was then employed for compound analysis and identification...
December 1, 2016: Talanta
Songqing Chen, Xingxiu Qin, Weixi Gu, Xiashi Zhu
Ionic liquids-β-cyclodextrin polymer (ILs-β-CDCP) was attached on Fe3O4 nanoparticles to prepare magnetic solid phase extraction agent (Fe3O4@ILs-β-CDCP). The properties and morphology of Fe3O4@ILs-β-CDCP were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction(XRD), size distribution and magnetic analysis. A new method of magnetic solid phase extraction (MSPE) coupled to ICP-OES for the speciation of Mn(II)/Mn(VII) in water samples was established...
December 1, 2016: Talanta
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"