1. Interactions of arabinogalactans with bacterial cellulose during its synthesis: structure and physical properties
Author: Dehui Lin, Patricia Lopez-Sanchez and Michael J.Gidley
Journal: Food Hydrocolloids
Abstract: Arabinogalactans (AGs) are plant cell wall constituents, some of which find applications in the food industry. However, there is very limited information about the interactions of AGs with other plant polysaccharides, in particular with cellulose. In the present work, we studied the interactions of two types of AGs, of different botanical origin and Ara/Gal ratio, with cellulose during and after its synthesis by Komagataeibacter xylinus (ATCC 53524). Solution depletion experiments and quartz crystal microbalance with dissipation monitoring show that these two kinds of AG are able to bind reversibly to pre-made cellulose, as also reflected by their relative incorporation in self-assembled composites during cellulose synthesis, with values of 18.0 % (w/w) for acacia AG (Ara:Gal 1:0.9) and 29.1% (w/w) for larch AG (Ara:Gal 1:1.3).
2. Multifunctional Tannic Acid (TA) and Lysozyme (Lys) Films Built by Layer by Layer for Potential Application on Implant Coating
Authors: Shuoshuo Yang, Yong Wang, Xiaoxiao Wu, Sunren Sheng, Tian Wang and Xingjie Zan
Journal: ACS Biomaterials-Science & Engineering
Abstract: A multifunctional (TA/Lys)n film, featuring with good antioxidant, fast cell attachment at early stage, enhanced osteogenesis and broad-spectrum antibacterial property, was constructed by layer-by-layer (LBL) method. The building process was monitored by quartz crystal microbalance with dissipation (QCM-D); the physical properties, such as topography, stiffness in dry and liquid state, and conformation of Lys in the film, were thoroughly characterized.
3. Wettability of quartz controlled by UV light irradiation using an azobenzene surfactant
Authors: Rui Dong, Xiaoming Jiang, Chunling Hao, Wei Xu, Huiyong Li, Yue Chen and Tian Xie
Journal: Colloids and Surfaces A: Physicochemical and Engineering Aspects
Abstract: Solids having controllable wettabilty have received much attention due to their great importance in many industrial fields. In this paper, the quartz surfaces and particles with reversibly switchable wettability have been studied. The wettability of quartz can be controlled by UV light irradiation in the presence of an azobenzene surfactant (AZO). The adsorption behavior of AZO at the quartz-liquid interface was investigated by the measurements of the surface tension, contact angle and Zeta potential. The adsorption process was monitored by the quartz crystal microbalance with dissipation (QCM-D).The results show that AZO has a strong tendency to adsorb at the quartz–liquid interface.
4. Hydrophobic and hydrophilic SiO2-based hybrids in the protection of sandstone for anti-salt damage
Authors: Mengjun Jia, Junyan Liang, Ling He, Xiang Zhao and Stefan Simon
Journal: Journal of Cultural Heritage
Abstract: The anti-salt damage of sandstone protected by hydrophobic and hydrophilic SiO2-based hybrids is evaluated in NaCl, Na2SO4 and NaCl-Na2SO4 salt-loaded hydrothermal aging (SLHA) cycles. Although both hydrophobic and hydrophilic SiO2-based hybrids could prevent the sandstone from salt damage through improving the matrix strength, the hydrophobic hybrid performs much better protection than hydrophilic one. The sandstone protected by hydrophobic SiO2-based hybrid shows nearly no salt-damage, which is attributed to its excellent water repellence, high adhesive strength and good compatibility with sandstone matrix.
5. High Performance Organic Electrochemical Transistors based on Conjugated Polyelectrolyte Copolymers
Authors: Philip Schmode, David Ohayon, Paul M. Reichstein, Achilleas Savva, Sahika Inal and Mukundan Thelakkat
Journal: Chemistry of Materials
Abstract: A new generation of polythiophene-based polyelectrolytes are reported to address fundamental issues in an organic electrochemical tran-sistor (OECT). In such devices, the semiconductor must be able to transport and store ions and to possess simultaneously a very high electronic mobility. For this, the ion-conducting 6-(thiophen-3-yl) hexane-1-sulfonate tetramethyl ammonium monomer (THS-TMA+) is copolymerized with the hole-conducting 3-hexylthiophene (3HT) to obtain copolymers, PTHS-TMA+-co-P3HT 1-3 with a gradient archi-tecture.
6. Magnetically Responsive Janus Nanoparticles Synthesized using Cellulosic Materials for Enhanced Phase Separation in Oily Wastewaters and Water-in-crude Oil Emulsions
Authors: Xiao He, Chen Liang, Qingxia Liu and Zhenghe Xu
Journal: Chemical Engineering Journal
Abstract: A new class of magnetically responsive Janus (M-Janus) nanoparticles was designed and synthesized by sequential adsorption of cellulosic materials: hydrophobic ethyl cellulose (EC) and hydrophilic carboxymethyl cellulose (CMC) on the opposite sides of magnetite (Fe3O4) nanoparticles. The adsorption study using quartz crystal microbalance with dissipation (QCM-D) proved the concept of proposed synthesis of magnetically responsive (M-Janus) nanoparticles. The adsorption of EC and CMC on magnetite nanoparticles was confirmed by zeta-potential measurements, thermogravimetric analysis (TGA), characterization using Fourier transform infrared spectroscopy (FTIR) and TEM.
7. Surface properties of adsorbed salivary components at a solid hydrophobic surface using a quartz crystal microbalance with dissipation (QCM–D)
Authors: Miodrag Glumac, Christos Ritzoulis and Jianshe Chen
Journal: Food Hydrocolloids
Abstract: Saliva is a human biological fluid that consists of many inorganic and organic substances such as salivary proteins, which play many roles during the consumption of foods. Some of these roles are not well understood while others still remain unknown. Very recent study from this group showed that saliva can function as an effective emulsifier during oral processing of dietary lipids. Therefore, our aim in this work was to establish surface functionality of salivary components at molecular level by using quartz crystal microbalance with dissipation (QCM–D) technique. Both unstimulated saliva and unstimulated dialyzed saliva were studied for their adsorption at a solid hydrophobic surface (SiO2), so that the role of smaller molecular weight salivary components can be examined. Based on the current model system, it was found that large molecular weight components of saliva play a compatibilizing role between water and oil. This allows adhesion to oral tissue surfaces, and could have implications for the perception of oil/fat inside the mouth.
8. Solvent Engineering for High‐Performance n‐Type Organic Electrochemical Transistors
Authors: Achilleas Savva, David Ohayon, Jokubas Surgailis, Alexandra F. Paterson, Tania C. Hidalgo, Xingxing Chen, Iuliana P. Maria, Bryan D. Paulsen, Anthony J. Petty II, Jonathan Rivnay, Iain McCulloch and Sahika Inal
Journal: Advanced Electronic Materials
Abstract: Organic electrochemical transistors (OECTs) exhibit strong potential for various applications in bioelectronics, especially as miniaturized, point‐of‐care biosensors, because of their efficient transducing ability. To date, however, the majority of reported OECTs have relied on p‐type (hole transporting) polymer mixed conductors, due to the limited number of n‐type (electron transporting) materials suitable for operation in aqueous electrolytes, and the low performance of those which exist. It is shown that a simple solvent‐engineering approach boosts the performance of OECTs comprising an n‐type, naphthalenediimide‐based copolymer in the channel. The addition of acetone, a rather bad solvent for the copolymer, in the chloroform‐based polymer solution leads to a three‐fold increase in OECT transconductance, as a result of the simultaneous increase in volumetric capacitance and electron mobility in the channel.
9. Effect of Interfacial Water on Nanomechanical Properties of Negatively Charged Floating Bilayers Supported on Gold Electrodes
Authors: Joanna Juhaniewicz-Debinska, Dorota Konarzewska and Slawomir Sek
Abstract: Floating lipid bilayers composed of phosphatidylglycerols and cardiolipin were deposited on gold electrodes pre-modified with 1-thio-β-D-glucose monolayer by spreading of small unilamellar vesicles. The resulting lipid membrane was homogenous and its thickness was ~5.0 nm. Electrochemical characterization combined with surface enhanced infrared absorption spectroscopy revealed that negative polarization of the electrode leads to accumulation of water molecules in the interfacial region between lipid membrane and the thioglucose film. Moreover, the buildup of water layer was demonstrated to affect the nanomechanical properties of the membrane.
10. Temperature-activated PEG surface segregation controls the protein repellency of polymers
Authors: N. Sanjeeva Murthy, Wenjie Wang, Sven D. Sommerfeld, David Vaknin and Joachim Kohn
Abstract: Poly(ethylene glycol) (PEG) is widely used to modulate the hydration states of biomaterials and is often applied to produce non-fouling surfaces. Here we present X-ray scattering data which show that non-fouling is caused the surface segregation of PEG, not just its presence in the bulk. We demonstrate a temperature-dependent trigger that transforms a PEG-containing substrate from a protein-adsorbing to a protein-repelling state. On films of poly(desaminotyrosyl-tyrosine-co-PEG carbonate) with high (20 wt %) PEG content, in which very little protein adsorption would have been expected, quartz crystal microbalance (QCM) data showed significant adsorption of fibrinogen (Fg) and bovine serum albumin (BSA) at 8 °C.