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Xianghui Gong, Jie Yao, Hongping He, Xixi Zhao, Xiaoyi Liu, Feng Zhao, Yan Sun, Yubo Fan
Assuring cell adhesion to an underlying biomaterial surface under blood flow is vital to functional vascular grafts design. In vivo endothelial cells (ECs) are located under the microenvironment of both surface topography of the basement membrane and the mechanical loading resulting from blood flow. Both topographical and mechanical factors should thus be considered when designing vascular grafts to enhance the flow-resistant EC adhesion. This study aims to investigate effects of integrating biomaterial surface topography and flow on EC adhesion, which was a deficit in previous studies...
May 2, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Arvind Chandrasekaran, Nikita Kalashnikov, Roni Rayes, Claire Wang, Jonathan Spicer, Christopher Moraes
Innovation in microfluidics-based biological research has been aided by the growing accessibility of versatile microscale fabrication techniques, particularly in rapid prototyping of elastomeric polydimethylsiloxane (PDMS) based devices. However, the use of PDMS presents considerable and often unexpected limitations, particularly in interpreting and validating biological data. To rapidly prototype microfluidic culture systems in conventional plastics commonly used in cell culture, we developed 'thermal scribing', a one-step micromachining technique in which thermoplastics are locally patterned by a heated tip, moving in user-controlled patterns...
May 19, 2017: Lab on a Chip
Liu Jiang, Huaming Qian, Gang Chen, Chunyan Li, Guangjun Yan, Yanling Luo, Peng Liu, Yashao Chen
In this study, micropatterns on polypropylene films were fabricated via plasma pretreatment and UV-initiated graft polymerization. Firstly, radio-frequency plasma, which does not significantly influence bulk attributes of substrates due to limited penetration depth, was utilized to activate polypropylene films. Then, different sizes of micropatterns of poly(hydroxyethyl methacrylate) (PHEMA) were fabricated on the polypropylene films via UV-initiated graft polymerization of hydroxyethyl methacrylate by using photo-masks...
May 2017: Journal of Biomaterials Applications
Toshiki Nishimura, Fuyuko Tamura, Sawako Kobayashi, Yasushi Tanimoto, Fumio Hayashi, Yuki Sudo, Yasuhiko Iwasaki, Kenichi Morigaki
Substrate-supported planar lipid bilayers (SPBs) are being utilized as a versatile model system of the biological membrane. However, the proximity between the solid support and membrane limits utility of SPBs for the functional analyses of membrane proteins. Here, we present a model membrane that can enlarge the distance between the substrate surface and the membrane by combining a stable scaffold of polymerized lipid bilayer with a hydrophilic polymer brush. A micropatterned SPB was generated by the lithographic polymerization of diacetylene lipids and subsequent incorporation of natural (fluid) lipid bilayers...
May 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Shuntaro Suzuki, Yoshikuni Teramoto
Structural polysaccharide nanocrystals (NCs) including cellulose nanocrystal have attracted attention. In order to broaden the range of application of the NCs, we can take advantage of their original characteristics by establishing simple and reasonable processing methods. We here demonstrate a micropatterning of animal cellular adhesion by inkjet printing of aqueous dispersions of cytocompatible chitinous NCs onto cellophane films. We display how to regulate the deposition form and two-dimensional shape of the chitinous NC micro-moldings using a research inkjet printer...
May 15, 2017: Biomacromolecules
K Nickmans, Ph Leclère, J Lub, D J Broer, A P H J Schenning
Oligo(dimethylsiloxane)-based reactive mesogens were prepared and shown to form room-temperature smectic phases which were 'frozen-in' by photopolymerization. Homeotropically aligned, nanostructured thin films were obtained by spincoating, and micropatterning was demonstrated. These hybrid reactive mesogens are suitable for the preparation of aligned nanostructured polymer thin films with potential applications ranging from stimuli responsive coatings to nanoporous membranes.
May 15, 2017: Soft Matter
David J Hughes, Tomasz Kostrzewski, Emma L Sceats
Liver disease represents a growing global health burden. The development of in vitro liver models which allow the study of disease and the prediction of metabolism and drug-induced liver injury in humans remains a challenge. The maintenance of functional primary hepatocytes cultures, the parenchymal cell of the liver, has historically been difficult with dedifferentiation and the consequent loss of hepatic function limiting utility. The desire for longer term functional liver cultures sparked the development of numerous systems, including collagen sandwiches, spheroids, micropatterned co-cultures and liver microphysiological systems...
January 1, 2017: Experimental Biology and Medicine
Cristiana Passiu, Antonella Rossi, Laetitia Bernard, Dennis Paul, John S Hammond, Wolfgang E S Unger, Nagaiyanallur V Venkataraman, Nicholas D Spencer
Micropatterns and nanopatterns of gold embedded in silver and titanium embedded in gold have been prepared by combining either photolithography or electron-beam lithography (EBL) with a glue-free template-stripping procedure. The obtained patterned surfaces have been topographically characterized by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM), showing a very low root-mean-square (RMS) roughness (<0.5 nm), high coplanarity between the two metals (maximum height difference ~2 nm) and topographical continuity at the bimetallic interface...
May 13, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
A V Radhakrishnan, Doorgesh S Jokhun, Saradha Venkatachalapathy, G V Shivashankar
The collective activity of several molecular motors and other active processes generate large forces for directional motion within the cell, which is vital for a multitude of cellular functions such as migration, division, contraction, transport, and positioning of various organelles. These processes also generate a background of fluctuating forces, which influence intracellular dynamics and thereby create unique biophysical signatures, which are altered in many diseases. In this study, we have used the nucleus as a probe particle to understand the microrheological properties of altered intracellular environments by using micropatterning to confine cells in two structurally and functionally extreme geometries...
May 9, 2017: Biophysical Journal
Mackenzie Ruthven, Kristin Robin Ko, Rishima Agarwal, John P Frampton
Aqueous two-phase systems have emerged as valuable tools for microscale analysis of cell growth and many other biotechnology applications. The most critical step in developing an aqueous two-phase system for a specific application is identifying the critical concentrations at which the polymer solutions phase-separate. Current techniques for determining these critical concentrations rely on laborious methods, highly specialized assays or computational methods that make this step difficult for non-specialists...
May 10, 2017: Analyst
Jiayi Zhao, Shuo Chen
Two kinds of possible movements of droplets (i.e. following or against topographic wettability gradient) on a micropatterned surface are investigated by using a particle-based method, many-body dissipative particle dynamics (MDPD). The displacement along wettability gradient and contact angles on both sides of the droplet are analyzed. The results show that the migration trajectory of the droplet is determined by coexistence of Cassie and Wenzel state, and unbalanced Young's force which are related to impact velocity, pillar height and surface tension etc...
May 9, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Hiroshi Sunami, Yusuke Shimizu, Junko Denda, Ikuko Yokota, Tomokazu Yoshizawa, Yukiko Uechi, Hitoshi Nakasone, Yasuyuki Igarashi, Hidehiro Kishimoto, Masayuki Matsushita
Here, a new technology was developed to selectively produce areas of high and low surface Young's modulus on biomedical polymer films using micropatterns. First, an elastic polymer film was adhered to a striped micropattern to fabricate a micropattern-supported film. Next, the topography and Young's modulus of the film surface were mapped using atomic force microscopy. Contrasts between the concave and convex locations of the stripe pattern were obvious in the Young's modulus map, although the topographical map of the film surface appeared almost flat...
May 5, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Shangwu Chen, Naoki Kawazoe, Guoping Chen
Porous scaffolds can be used to engineer 3D tissues for tissue repair. Coculture of vascular endothelial cells and the cells of target tissue in porous scaffolds is promising to engineer vascularized tissue. However, it is difficult to induce regeneration of anisotropic tissues such as muscle and nerve that have well aligned cells, blood vessels and extracellular matrix by using conventional porous scaffolds with homogeneous pore structures. In this study, we developed collagen porous scaffolds with parallel and concave microgrooves by using micropatterned ice template and freeze-drying...
May 4, 2017: Tissue Engineering. Part C, Methods
Seungo Gim, Illhwan Lee, Jae Yong Park, Jong-Lam Lee
A flexible hazy substrate (FHS) with embedded air bubbles to increase light extraction efficiency of organic light-emitting diodes (OLEDs) is reported. In order to embed the air bubbles in the flexible substrate, micropatterned substrates are fabricated by plasma treatment, and then coated with a planarization layer. During the planarization layer coating, air bubbles are trapped between the substrate and the planarization layer. The haze of the FHS can be controlled from 1.7% to 68.4% by changing the size of micropatterns by adjusting the plasma treatment time...
May 2, 2017: Small
Christine Lin, Salman R Khetani
Drug clearance rates from the body can determine drug exposure that can affect efficacy or toxicity. Thus, accurate prediction of drug clearance during preclinical development can help guide dose selection in humans, but animal testing is not always predictive of human outcomes. Because hepatic drug metabolism is a rate-limiting step in the overall clearance of many drugs, primary human hepatocytes (PHHs) in suspension cultures or monolayers are used for drug clearance predictions. Yet, the precipitous decline in drug metabolism capacity can lead to significant underestimation of clearance rates, particularly for low turnover compounds that have desirable one-pill-a-day dosing regimens...
May 2, 2017: Current Protocols in Toxicology
Valentina Bonfrate, Daniela Manno, Antonio Serra, Luca Salvatore, Alessandro Sannino, Alessandro Buccolieri, Tiziano Serra, Gabriele Giancane
The development of biocompatible collagen substrates able to conduct electric current along specific pathways represent an appealing issue in tissue engineering, since it is well known that electrical stimuli significantly affects important cell behaviour, such as proliferation, differentiation, directional migration, and, therefore, tissue regeneration. In this work, a cheap and easy approach was proposed to produce collagen-based films exhibiting enhanced electrical conductivity, through the simple manipulation of a weak external magnetic trigger...
April 22, 2017: Journal of Colloid and Interface Science
Soonyong So, Ryan C Hayward
We demonstrate sequential folding of micropatterned polymer actuators by tuning the upper critical solution temperature (UCST) of poly(N-isopropylacrylamide) (PNIPAM) copolymers in the ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoro-methylsulfonyl) imide. Incorporation of comonomers having different hydrogen-bonding capacities, acrylic acid and methyl acrylate, is shown to shift the UCST of PNIPAM to higher and lower temperatures, respectively. Relying on the ability to tune the transition temperature through copolymerization along with the wide thermal range afforded by the IL as a solvent, we fabricated a photopatterned self-folding device which shows reversible and sequential bending of three sets of hinges...
April 28, 2017: ACS Applied Materials & Interfaces
Jungil Choi, Hyun Yong Jeong, Gi Yoon Lee, Sangkwon Han, Shinhun Han, Bonghwan Jin, Taegeun Lim, Shin Kim, Dong Young Kim, Hee Chan Kim, Eui-Chong Kim, Sang Hoon Song, Taek Soo Kim, Sunghoon Kwon
For the timely treatment of patients with infections in bloodstream and cerebrospinal fluid, a rapid antimicrobial susceptibility test (AST) is urgently needed. Here, we describe a direct and rapid antimicrobial susceptibility testing (dRAST) system, which can determine the antimicrobial susceptibility of bacteria from a positive blood culture bottle (PBCB) in six hours. The positive blood culture sample is directly mixed with agarose and inoculated into a micropatterned plastic microchip with lyophilized antibiotic agents...
April 25, 2017: Scientific Reports
Aldo Leal-Egaña, Gaelle Letort, Jean-Louis Martiel, Andreas Christ, Timothée Vignaud, Caroline Roelants, Odile Filhol, Manuel Théry
Tumor development progresses through a complex path of biomechanical changes leading first to cell growth and contraction followed by cell de-adhesion, scattering and invasion. Tumorigenic factors may act specifically on one of these steps or have wider spectrum of actions, leading to a variety of effects and thus sometimes to apparent contradictory outcomes. Here we used micropatterned lines of collagen type-I/fibronectin on deformable surfaces to standardize cell behavior and to measure simultaneously cell size, speed of motion and the magnitude of the associated traction forces at the level of a single cell...
April 20, 2017: Molecular Biology of the Cell
Viktoriia Barreau, Dan Yu, René Hensel, Eduard Arzt
Micropatterned polymer surfaces that operate at various temperatures are required for emerging technical applications such as handling of objects or space debris. As the mechanical properties of polymers can vary significantly with temperature, adhesion performance can exhibit large variability. In the present paper, we experimentally study temperature effects on the adhesion of micropatterned adhesives (pillar length 20µm, aspect ratios 0.4 and 2) made from three different polymers, i.e., polydimethylsiloxane (PDMS), perfluoropolyether dimethacrylate (PFPEdma), and polyurethane (PU-ht)...
April 7, 2017: Journal of the Mechanical Behavior of Biomedical Materials
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