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Karin Fromell, Yi Yang, Kristina Nilsson Ekdahl, Bo Nilsson, Mattias Berglin, Hans Elwing
In previous investigations, the authors have examined the adsorption of albumin, immunoglobulin, and fibrinogen to a series of acrylate polymers with different backbone and side-group flexibility. The authors showed that protein adsorption to acrylates with high flexibility, such as poly(lauryl methacrylate) (PLMA), tends to preserve native conformation. In the present study, the authors have continued this work by examining the conformational changes that occur during the binding of complement factor 3 (C3) and coagulation factor XII (FXII)...
June 21, 2017: Biointerphases
Hamza Chouirfa, Margaret D M Evans, David G Castner, Penny Bean, Dimitri Mercier, Anouk Galtayries, Céline Falentin-Daudré, Véronique Migonney
This contribution reports on grafting of bioactive polymers such as poly(sodium styrene sulfonate) (polyNaSS) onto titanium (Ti) surfaces. This grafting process uses a modified dopamine as an anchor molecule to link polyNaSS to the Ti surface. The grafting process combines reversible addition-fragmentation chain transfer polymerization, postpolymerization modification, and thiol-ene chemistry. The first step in the process is to synthetize architecture controlled polyNaSS with a thiol end group. The second step is the adhesion of the dopamine acrylamide (DA) anchor onto the Ti surfaces...
June 14, 2017: Biointerphases
Rahula Janiš, Vladimír Pata, Pavlína Egner, Jana Pavlačková, Andrea Zapletalová, Kristina Kejlová
The aim of this research was to evaluate mutual interchangeability of four principally different biometric instrumental techniques designed for objective measurement of changes in the physical, mechanical, and topographical properties of the skin surface treated with commercial antiaging cosmetic products with hyaluronic acid. The following instrumental devices were used: Visioscope PC 35, Corneometer Multiprobe Adapter MPA 6, Reviscometer RVM 600, and 3D scanner Talysurf CLI 500. The comparison of the individual methods was performed using cluster analysis...
June 14, 2017: Biointerphases
Kirsten N Cicotte, Jamie A Reed, Phuong Anh H Nguyen, Jacqueline A De Lora, Elizabeth L Hedberg-Dirk, Heather E Canavan
Poly(N-isopropyl acrylamide) (pNIPAM) is a "smart" polymer that responds to changes in altering temperature near physiologically relevant temperatures, changing its relative hydrophobicity. Mammalian cells attach to pNIPAM at 37 °C and detach spontaneously as a confluent sheet when the temperature is shifted below the lower critical solution temperature (∼32 °C). A variety of methods have been used to create pNIPAM films, including plasma polymerization, self-assembled monolayers, and electron beam ionization...
June 13, 2017: Biointerphases
Allan S Hoffman
No abstract text is available yet for this article.
June 12, 2017: Biointerphases
Hannah J Askew, Mirren Charnley, Karyn L Jarvis, Sally L McArthur
Model lipid vesicle and supported lipid bilayer (SLB) systems are used in a variety of applications including biosensing, cell membrane mimics, and drug delivery. Exposure of a surface to a vesicle solution provides a straightforward method for creating such systems via vesicle adsorption and collapse. However, this process is complex and the relationship between the surface physicochemical properties and vesicle collapse is poorly understood. Plasma polymers are thin conformal films that can be applied to a variety of materials to modify surface properties...
June 7, 2017: Biointerphases
Saowalak Krungchanuchat, Titipun Thongtem, Somchai Thongtem, Chalermchai Pilapong
Herein, a new magnetic resonance imaging (MRI) agent based on molecular nanoparticles of iron(III)-tannic complexes (Fe-TA NPs) is reported. The paramagnetic and molecularlike Fe-TA NPs were successfully synthesized at room temperature within a few minutes without the use of any toxic agents or expensive equipment. The coordination states of the Fe-TA NPs were pH-dependent. The r1 relaxivity values of the bis-dominated and tris-dominated structures of the Fe-TA NPs were determined to be 6.31 and 5.24 mM(-1 )s(-1), respectively, by using a Philips Achieva 1...
June 7, 2017: Biointerphases
Peter W Akers, Nam Cao Hoai Le, Andrew R J Nelson, Milena McKenna, Christy O'Mahony, Duncan J McGillivray, Vladimir Gubala, David E Williams
The authors present surface engineering modifications through chemistry of poly(methylmethacrylate) (PMMA) that have dramatic effects on the result of surface-bound fluorescence immunoassays, both for specific and nonspecific signals. The authors deduce the most important effect to be clustering of antibodies on the surface leading to significant self-quenching. Secondary effects are attributable to the formation of sparse multilayers of antibody. The authors compare PMMA as an antibody support surface with ultraviolet-ozone oxidized PMMA and also to substrates that were, after the oxidation, surface modified by a four-unit poly(ethyleneglycol) carboxylic acid (PEG4), a branched tricarboxylic acid, and a series of carboxylic acid-terminated dendrimers, from generation 1...
June 6, 2017: Biointerphases
Hongjie Fan, Daohui Zhao, Yingtu Li, Jian Zhou
Two-dimensional molybdenum disulfide (MoS2) has attracted intense interest owing to its unique properties and promising biosensor applications. To develop effective biocompatible platforms, it is crucial to understand the interactions between MoS2 and biological molecules such as proteins, but little knowledge exists on the orientation and conformation of proteins on the MoS2 surface at the molecular level. In this work, the lysozyme adsorption on the MoS2 surface was studied by molecular dynamics simulations, wherein six different orientations were selected based on the different faces of lysozyme...
June 2, 2017: Biointerphases
Hanqi Wang, Fang Cheng, Wei He, Jiaohui Zhu, Gang Cheng, Jingping Qu
This paper reported a facile strategy for the one-pot synthesis of vinyl sulfone (VS) group terminated hydrogel precursors [poly(ethylene) glycol (PEG)-VS] and PEG hydrogels via catalytic oxa-Michael reaction. Nine potential catalysts were investigated for the reaction between PEG and divinyl sulfone, among which 4-dimethylaminopyridine (DMAP) prevailed for its high catalytic activity. DMAP produced PEG-VS with a conversion of more than 90% in 2 h under a solvent-free condition at room temperature, which significantly simplifies the synthesis of PEG-VS...
June 1, 2017: Biointerphases
Nurit Adiram-Filiba, Avital Schremer, Eli Ohaion, Merav Nadav-Tsubery, Tammi Lublin-Tennenbaum, Keren Keinan-Adamsky, Gil Goobes
Deriving the conformation of adsorbed proteins is important in the assessment of their functional activity when immobilized. This has particularly important bearings on the design of contemporary and new encapsulated enzyme-based drugs, biosensors, and other bioanalytical devices. Solid-state nuclear magnetic resonance (NMR) measurements can expand our molecular view of proteins in this state and of the molecular interactions governing protein immobilization on popular biocompatible surfaces such as silica...
May 31, 2017: Biointerphases
King Tuo Yip, Xueyin Zhong, Nadia Seibel, Oliver Arnolds, Miriam Schöpel, Raphael Stoll
The heparin binding site (Hep II) of fibronectin plays a major role in tumor cell metastasis. Its interaction with heparan sulfate proteoglycans occurs in a variety of physiological processes including focal adhesion and migration. The melanoma inhibitory activity (MIA) is an important protein that is functionally involved in melanoma development, progression, and tumor cell invasion. After its secretion by malignant melanoma cells, MIA interacts with fibronectin and thereby actively facilitates focal cell detachment from surrounding structures and strongly promotes tumor cell invasion and the formation of metastases...
May 31, 2017: Biointerphases
Sofia Babanova, Ivana Matanovic, Jose Cornejo, Orianna Bretschger, Kenneth Nealson, Plamen Atanassov
Extracellular electron transfer (EET) is intrinsically associated with the core phenomena of energy harvesting/energy conversion in natural ecosystems and biotechnology applications. However, the mechanisms associated with EET are complex and involve molecular interactions that take place at the "bionano interface" where biotic/abiotic interactions are usually explored. This work provides molecular perspective on the electron transfer mechanism(s) employed by Shewanella oneidensis MR-1. Molecular docking simulations were used to explain the interfacial relationships between two outer-membrane cytochromes (OMC) OmcA and MtrC and riboflavin (RF) and flavin mononucleotide (FMN), respectively...
May 31, 2017: Biointerphases
Katarzyna Kępa, David J T Hill, Lisbeth Grøndahl
The modification of biomaterials by radiation induced grafting is a promising method to improve their bioactivity. Successful introduction of carboxyl and amine functional groups on the surface of a polytetrafluoroethylene membrane was achieved by grafting of acrylic acid (AA) and 2-aminoethyl methacrylate hydrochloride (AEMA) using simultaneous gamma irradiation grafting. Chemical characterization by attenuated total reflectance Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy confirmed the presence of amine and carboxylate functionalities and indicated that all protonated amines formed ion pairs with carboxyl groups, but not all carboxyl are involved in ion pairing...
May 30, 2017: Biointerphases
Beytullah Ozgur, Mehmet Sayar
Protein aggregation is a hallmark of neurodegenerative disorders. In this group of brain-related disorders, a disease-specific "host" protein or fragment misfolds and adopts a metastatic, aggregate-prone conformation. Often, this misfolded conformation is structurally and thermodynamically different from its native state. Intermolecular contacts, which arise in this non-native state, promote aggregation. In this regard, understanding the molecular principles and mechanisms that lead to the formation of such a non-native state and further promote the formation of the critical nucleus for fiber growth is essential...
May 24, 2017: Biointerphases
Bonnie J Tyler, Andrew Hook, Andreas Pelster, Paul Williams, Morgan Alexander, Heinrich F Arlinghaus
Catheter associated urinary tract infections are the most common health related infections worldwide, contributing significantly to patient morbidity and mortality and increased health care costs. To reduce the incidence of these infections, new materials that resist bacterial biofilm formation are needed. A composite catheter material, consisting of bulk poly(dimethylsiloxane) (PDMS) coated with a novel bacterial biofilm resistant polyacrylate [ethylene glycol dicyclopentenyl ether acrylate (EGDPEA)-co-di(ethyleneglycol) methyl ether methacrylate (DEGMA)], has been proposed...
May 23, 2017: Biointerphases
Josh Smith, Kayla G Sprenger, Rick Liao, Andrea Joseph, Elizabeth Nance, Jim Pfaendtner
Enzymes play a critical role in many applications in biology and medicine as potential therapeutics. One specific area of interest is enzyme encapsulation in polymer nanostructures, which have applications in drug delivery and catalysis. A detailed understanding of the mechanisms governing protein/polymer interactions is crucial for optimizing the performance of these complex systems for different applications. Using a combined computational and experimental approach, this study aims to quantify the relative importance of molecular and mesoscale driving forces to protein release from polymeric nanoparticles...
May 19, 2017: Biointerphases
Luisa A Scudeller, Selvi Srinivasan, Alexandre M Rossi, Patrick S Stayton, Gary P Drobny, David G Castner
Adsorption isotherms, circular dichroism (CD) spectroscopy, x-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to investigate the adsorption of human osteocalcin (hOC) and decarboxylated (i.e., Gla converted back to Glu) hOC (dhOC) onto various calcium phosphate surfaces as well as silica surfaces. The adsorption isotherms and XPS nitrogen signals were used to track the amount of adsorbed hOC and dhOC. The intensities of key ToF-SIMS amino acid fragments were used to assess changes in the structure of adsorbed hOC and dhOC...
May 18, 2017: Biointerphases
Tigran M Abramyan, David L Hyde-Volpe, Steven J Stuart, Robert A Latour
The use of standard molecular dynamics simulation methods to predict the interactions of a protein with a material surface have the inherent limitations of lacking the ability to determine the most likely conformations and orientations of the adsorbed protein on the surface and to determine the level of convergence attained by the simulation. In addition, standard mixing rules are typically applied to combine the nonbonded force field parameters of the solution and solid phases the system to represent interfacial behavior without validation...
May 17, 2017: Biointerphases
James W Bauer, Li-Chong Xu, Erwin A Vogler, Christopher A Siedlecki
Studies of the activation of FXII in both platelet poor plasma and in neat buffer solutions were undertaken for a series of mixed thiol self-assembled monolayers spanning a broad range of water wettability. A wide spectrum of carboxyl/methyl-, hydroxyl/methyl-, and amine/methyl-thiol modified surfaces were prepared, characterized, and then utilized as the procoagulant materials in a series of FXII activation studies. X-ray photoelectron spectroscopy was utilized to verify the sample surface's thiol composition and contact angles measured to determine the sample surface's wettability...
May 17, 2017: Biointerphases
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