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Tony W Hsiao, Patrick A Tresco, Vladimir Hlady
The surface concentration gradient of two extracellular matrix (ECM) macromolecules was developed to study the migratory and morphological responses of astrocytes to molecular cues typically found in the central nervous system injury environment. The gradient, prepared using microcontact printing, was composed of randomly positioned micrometer-sized dots of aggrecan (AGG) printed on a substrate uniformly coated with laminin (LN). AGG dots were printed in an increasing number along the 1000 μm long and 50 μm wide gradient area which had on each end either a full surface coverage of AGG or LN...
September 11, 2017: Biointerphases
Lifang Niu, Thorsten Wohland, Wolfgang Knoll, Ingo Köper
Tethered bimolecular lipid membranes are solid supported membrane systems, which provide a versatile model platform for the study of many membrane related processes. Here, such an architecture has been used to study the interaction of the small synthetic antimicrobial peptide, V4, with membranes of various mixed lipid compositions, including membranes containing bacterial lipids. By investigating the binding of the peptide using a range of surface analytical techniques such as surface plasmon resonance and surface plasmon field-enhanced fluorescence spectroscopy as well as electrochemical impedance spectroscopy, a clear preference of the peptide for negatively charged membranes over zwitterionic ones has been shown...
August 31, 2017: Biointerphases
Thomas D Michl, Carla Giles, Piotr Mocny, Kathryn Futrega, Michael R Doran, Harm-Anton Klok, Hans J Griesser, Bryan R Coad
There is a need for coatings for biomedical devices and implants that can prevent the attachment of fungal pathogens while allowing human cells and tissue to appose without cytotoxicity. Here, the authors study whether a poly(2-hydroxyethylmethacrylate) (PHEMA) coating can suppress attachment and biofilm formation by Candida albicans and whether caspofungin terminally attached to surface-tethered polymeric linkers can provide additional benefits. The multistep coating scheme first involved the plasma polymerization of ethanol, followed by the attachment of α-bromoisobutyryl bromide (BiBB) onto surface hydroxyl groups of the plasma polymer layer...
August 29, 2017: Biointerphases
Nicolás E Muzzio, Miguel A Pasquale, Sergio E Moya, Omar Azzaroni
The layer-by-layer assembly of polyelectrolyte multilayers (PEMs) from natural or synthetic polyelectrolytes constitutes a very versatile and simple strategy to modify surfaces and modulate cell behavior. PEMs assembled from natural polyelectrolytes are very appealing for biological and medical applications due to their high biocompatibility. However, PEMs from natural polyelectrolytes display poor cell adhesion as they are soft materials with an elasticity modulus of a few kilopascal. In this report, the authors present results on the modulation of cell adhesion of different immortalized cell lines by PEMs...
August 29, 2017: Biointerphases
Veronika Rink, Christine Müller-Renno, Christiane Ziegler, Mario Braun, Kajohn Boonrod, Gabriele Krczal
Plant viruses which are self-assembled on a substrate are interesting building blocks in nanobiotechnology, in particular, for the creation of 2D ordered structures. In this article, the self-assembly of different genetically modified types of the tomato bushy stunt virus spin-coated on pristine silicon was investigated by scanning force and scanning electron microscopy. Amino acid side chains were integrated in the capsids of the viruses by extending the coat protein with different charged amino acid clusters (tetra-aspartate-hexa-histidine, hexa-aspartate, or tetra-arginine-tags)...
August 22, 2017: Biointerphases
Marcelle B M Spera, Thiago B Taketa, Marisa M Beppu
Surfaces are responsible for important interactions of biomaterials since they create the interface with the biological environment and affect the response that the body will have to the material. Surface roughness and morphology have great impact on the material performance, affecting cell, bacterial, and biomolecular adhesion. Thin films of chitosan and carboxymethyl cellulose were produced by layer-by-layer deposition at different pH values and had their surface growth process studied throughout roughness measurements...
August 21, 2017: Biointerphases
Xianfeng Li, Jia Jia, Ying Mei, Robert A Latour
Peptide-functionalized (PF) hydrogels are being widely investigated by the tissue engineering and regenerative medicine communities for a broad range of applications because of their unique potential to mimic the natural extracellular matrix and promote tissue regeneration. In order for these complex material systems to perform their intended bioactive function (e.g., cell signaling), the peptides that are tethered to the hydrogel matrix must be accessible at the hydrogel surface for cell-receptor binding. The factors influencing the surface accessibility of the tethered peptide mainly include the length of the tethers, the loading (i...
August 18, 2017: Biointerphases
Wenchao Wei, Yanyan Zhang, Rachel Komorek, Andrew Plymale, Rujia Yu, Bingchen Wang, Zihua Zhu, Fanghua Liu, Xiao-Ying Yu
The aggregation of syntrophic Geobacter metallireducens and Geobacter sulfurreducens is beneficial for enhancing direct interspecies electron transfer (DIET). Although DIET was suspected to occur on the microbial community surface, the surface chemical speciation of such cocultured communities remains unclear. In order to better understand surface interactions related to DIET, the authors characterized a series of samples associated with syntrophic G. metallireducens and G. sulfurreducens using surface sensitive time-of-flight secondary ion mass spectrometry (ToF-SIMS)...
August 18, 2017: Biointerphases
Robert M T Madiona, Nicholas G Welch, Judith A Scoble, Benjamin W Muir, Paul J Pigram
Determination of a limit of detection (LoD) for surface bound antibodies is crucial for the development and deployment of sensitive bioassays. The measurement of very low concentrations of surface bound antibodies is also important in the manufacturing of pharmaceutical products such as antibody-conjugated pharmaceuticals. Low concentrations are required to avoid an immune response from the target host. Enzyme-linked immunosorbent assay (ELISA), x-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to determine the LoD for the surface bound antibody (antiepidermal growth factor receptor antibody) on silicon substrates...
August 11, 2017: Biointerphases
Fidal Vallam Thodi, Abhilash Thendiyammal, Balasubrahmaniyam Mukundakumar, Kasiviswanathan Subbiah, Chandra T Sainathan
Aqueous stability of sputter coated ZnO thin films were studied on two base materials, viz., polycarbonate (PC) and glass. The films showed higher stability on PC compared to glass, when exposed to aqueous buffered solution at pH-7.4, as studied by x-ray diffraction, surface reflectometry, and inductively coupled plasma-optical emission spectroscopy. Glucose oxidase (GOx) and cholesterol oxidase (Chl.Ox.) were used as model enzymes to study their electrochemical interaction with ZnO/PC. GOx showed a higher immobilization on ZnO/PC with an activity of 9...
August 2, 2017: Biointerphases
Ryo Furuta, Naoyuki Kurake, Keigo Takeda, Kenji Ishikawa, Takayuki Ohta, Masafumi Ito, Hiroshi Hashizume, Hiromasa Tanaka, Hiroki Kondo, Makoto Sekine, Masaru Hori
The multiplex coherent anti-Stokes Raman scattering microscopy allowed label-free visualization of cytoplasmic lipid droplets (LDs). The LDs, which act to conserve energy storage, are usually accumulated during the normal apoptosis of HeLa cells with activation of caspase-3/7 leading to downregulation of the fatty acid catabolism pathways. During cultivating in nonthermal plasma-activated medium (PAM), while the activation of caspase-3/7 was induced, the authors found that a dynamic exhaustion of the intracellular LDs, underlying the metabolic mechanism of the PAM-induced apoptotic cell death of HeLa cells...
August 2, 2017: Biointerphases
Sergey A Golyshev, Anna K Berkovich, Ruslan Yu Yakovlev, Dmitry M Bystrov, Nikita M Ivanov, Galina N Balandina, Galina N Rudenskaya
Two novel conjugates of detonation nanodiamonds (dNDs) with the proteolytic enzymes chymotrypsin and papain were synthesized. The synthesis was performed via functionalization of the dNDs' surface with acidic/alkali treatment followed by carbodiimide-mediated protein binding. Covalent binding of the enzymes was confirmed by Fourier transform infrared spectrographic analysis and high-performance liquid chromatography (HPLC) amino acid analysis. HPLC also proved the preservation of the enzymes' composition during synthesis...
July 28, 2017: Biointerphases
Rita La Spina, Valentina Spampinato, Douglas Gilliland, Isaac Ojea-Jimenez, Giacomo Ceccone
In this paper, the authors have investigated the effects of different cleaning methods (centrifugation and dialysis) on the surface chemistry and composition of 15 nm sodium citrate stabilized gold nanoparticles. The nuclear magnetic resonance (NMR) results indicate that three centrifugation cycles are sufficient to remove most of the citrate molecules, while centrifuged liquid sedimentation and dynamic light scattering data reveal some degree of nanoparticle aggregation when three centrifugation cycles are exceeded...
July 27, 2017: Biointerphases
Elisa Castagnola, Stefano Carli, Maria Vomero, Alice Scarpellini, Mirko Prato, Noah Goshi, Luciano Fadiga, Sam Kassegne, Davide Ricci
The authors present an electrochemically controlled, drug releasing neural interface composed of a glassy carbon (GC) microelectrode array combined with a multilayer poly(3,4-ethylenedioxythiophene) (PEDOT) coating. The system integrates the high stability of the GC electrode substrate, ideal for electrical stimulation and electrochemical detection of neurotransmitters, with the on-demand drug-releasing capabilities of PEDOT-dexamethasone compound, through a mechanically stable interlayer of PEDOT-polystyrene sulfonate (PSS)-carbon nanotubes (CNT)...
July 13, 2017: Biointerphases
Yizhi Meng, Meghan E Faillace, Kathryn Dorst, Samantha J Palmaccio, Lisa M Miller, Yi-Xian Qin
Osteoporosis is a skeletal disorder that is characterized by the loss of bone mineral density (BMD) resulting in increased risk of fracture. However, it has been shown that BMD is not the only indicator of fracture risk, as the strength of bone depends on a number of factors, including bone mass, architecture and material properties. Physiological mineral deposition requires the formation of a properly developed extracellular matrix (ECM), which recruits calcium and phosphate ions into the synthesis of apatite crystals...
July 10, 2017: Biointerphases
Morgan R Alexander, Paul Williams
Often the view is expressed that water contact angle (WCA) or other wettability/surface energy measurements made on a material surface can be used to predict cellular attachment to materials, e.g., bacteria attach to hydrophobic surfaces. In this article, the authors present a perspective emerging from their work that has failed to find relationships between WCA and microbial and stem cell attachment within large diversity material libraries and compare with the literature concluding that such simple rules are (unfortunately) wholly inadequate to explain cell-material interactions...
July 6, 2017: Biointerphases
Marisa L Sylvester, Buddy D Ratner
The development of biomaterials that promote tissue reconstruction and regeneration can reduce the low level, chronic inflammation and encapsulation that impact the performance of today's medical devices. Specifically, in the case of implantable sensors, the host response often leads to poor device performance that discourages permanent implantation. Our goal is to present on medical implants bioactive molecules that can promote healing rather than scarring. Localized delivery of these molecules would also minimize the possibility of adverse tissue reactions elsewhere in the body...
June 28, 2017: Biointerphases
Tobias Weidner
No abstract text is available yet for this article.
June 28, 2017: Biointerphases
Helen E Ferreira, Gary P Drobny
In nature, organisms including diatoms, radiolaria, and marine sponges use proteins, long chain polyamines, and other organic molecules to regulate the assembly of complex silica-based structures. Here, the authors investigate structural features of small peptides, designed to mimic the silicifying activities of larger proteins found in natural systems. LKα14 (Ac-LKKLLKLLKKLLKL-C), an amphiphilic lysine/leucine repeat peptide with an α-helical secondary structure at polar/apolar interfaces, coprecipitates with silica to form nanospheres...
June 27, 2017: Biointerphases
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
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