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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
Alexandre J Ribeiro, Olivier Schwab, Mohammad A Mandegar, Yen-Sin Ang, Bruce R Conklin, Deepak Srivastava, Beth L Pruitt
Rationale: During each beat, cardiac myocytes generate the mechanical output necessary for heart function through contractile mechanisms that involve shortening of sarcomeres along myofibrils. Human induced pluripotent stem cells can be differentiated into cardiac myocytes that model cardiac contractile mechanical output more robustly when micropatterned into physiological shapes. Quantifying the mechanical output of these cells enables us to assay cardiac activity in a dish. Objective: We sought to develop a computational platform that integrates analytical approaches to quantify the mechanical output of single micropatterned cardiac myocytes from microscopy videos...
April 11, 2017: Circulation Research
Julian Schneider, Wanlong Zhang, Abhishek K Srivastava, Vladimir G Chigrinov, Hoi S Kwok, Andrey L Rogach
Photo-alignment technology provides high alignment quality with an exceptional control over the local director of liquid crystals. Due to the reorientation ability of sulfonic azo dye molecules, they offer high azimuthal and polar anchoring energy with a low pretilt angle for the orientation of liquid crystals and liquid crystal composites. In this work, we make use of this approach to align thin film composites of light-emitting semiconductor nanorods dispersed in a liquid crystal polymer into both one-dimensional and two-dimensional micro-scale patterns...
April 10, 2017: Nano Letters
Kenta Homma, Tsukuru Masuda, Aya Mizutani Akimoto, Kenichi Nagase, Kazuyoshi Itoga, Teruo Okano, Ryo Yoshida
The propagation control of chemical waves via a pentagonal patterned structure in a self-oscillating polymer brush composed of N-isopropylacrylamide and a metal catalyst for the Belousov-Zhabotinsky (BZ) reaction is reported. The patterned self-oscillating polymer brush is prepared by combining surface-initiated atom transfer radical polymerization and maskless photolithography. Surface modification is confirmed by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, 3D measuring laser microscopy, and fluorescence microscopy...
April 6, 2017: Small
Yaowen Liu, Tian Xia, Jiaojun Wei, Qingjie Liu, Xiaohong Li
The spatial arrangement of cardiac myocytes (CMs) and other non-myocytes scaffolds, closely resembling native tissue, is essential to control the CM morphology and function for cardiac tissue regeneration. In the current study, micropatterned fibrous scaffolds were developed to establish a CM co-culture system with cardiac fibroblasts (CFs) and endothelial cells (ECs) as a potential in vitro drug screening model. To pursue a biomimetic approach to influence CM behaviors, strip, oval and wave-patterned mats were constructed by deposition of electrospun fibers on lithographic collectors, followed by precise stacking for cell co-cultures...
April 6, 2017: Nanoscale
G Criscenti, A Vasilevich, A Longoni, C De Maria, C A van Blitterswijk, R Truckenmuller, G Vozzi, J De Boer, L Moroni
Micro- and nano-topographies of scaffold surfaces play a pivotal role in tissue engineering applications, influencing cell behavior such as adhesion, orientation, alignment, morphology and proliferation. In this study, a novel microfabrication method based on the combination of soft-lithography and electrospinning for the production of micro-patterned electrospun scaffolds was proposed. Subsequently, a 3D screening device for electrospun meshes with different micro-topographies was designed, fabricated and biologically validated...
March 31, 2017: Acta Biomaterialia
Youngjin Park, Jongwon Shim, Suyeon Jeong, Gi-Ra Yi, Heeyeop Chae, Jong Wook Bae, Sang Ouk Kim, Changhyun Pang
Flexible thin-film sensors have been developed for practical uses in invasive or noninvasive cost-effective healthcare devices, which requires high sensitivity, stretchability, biocompatibility, skin/organ-conformity, and often transparency. Graphene nanoplatelets can be spontaneously assembled into transparent and conductive ultrathin coatings on micropatterned surfaces or planar substrates via a convective Marangoni force in a highly controlled manner. Based on this versatile graphene assembled film preparation, a thin, stretchable and skin-conformal sensor array (144 pixels) is fabricated having microtopography-guided, graphene-based, conductive patterns embedded without any complicated processes...
March 29, 2017: Advanced Materials
Brenton R Ware, Michael McVay, Wendy Y Sunada, Salman R Khetani
Global gene expression profiling is useful for elucidating a drug's mechanism of action (MOA) on the liver; however, such profiling in rats is not very sensitive for predicting human drug-induced liver injury, while de-differentiated monolayers of primary human hepatocytes (PHHs) do not permit chronic drug treatment. In contrast, micropatterned co-cultures (MPCCs) containing PHH colonies and 3T3-J2 fibroblasts maintain a stable liver phenotype for 4-6 weeks. Here, we used MPCCs to test the hypothesis that global gene expression patterns in stable PHHs can be used to distinguish clinical hepatotoxic drugs from their non-liver-toxic analogs and understand the MOA prior to the onset of overt hepatotoxicity...
March 24, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
Keisuke Sekine, Takanori Takebe, Hideki Taniguchi
Here, we describe a protocol to develop a three-dimensional (3D) liver bud-like tissue from human iPSCs in vitro. This method mainly consists of two parts: (1) hepatic endoderm (HE) differentiation from human iPSCs in 2D culture and (2) co-culturing iPSC-HE with endothelial and mesenchymal cells. First, iPSCs were differentiated into definitive endoderm (DE) cells, and the DE cells were differentiated into HE cells, which were then co-cultured with endothelial cells and mesenchymal cells on Matrigel-coated plastic plates or micropattern plates...
2017: Methods in Molecular Biology
Michael J Raymond, Poulomi Ray, Gurleen Kaur, Michael Fredericks, Ajay V Singh, Leo Q Wan
Intrinsic cell chirality has been implicated in the left-right (LR) asymmetry of embryonic development. Impaired cell chirality could lead to severe birth defects in laterality. Previously, we detected cell chirality with an in vitro micropatterning system. Here, we demonstrate for the first time that chirality can be quantified as the coordination of multiaxial polarization of individual cells and nuclei. Using an object labeling, connected component based method, we characterized cell chirality based on cell and nuclear shape polarization and nuclear positioning of each cell in multicellular patterns of epithelial cells...
February 2017: Cellular and Molecular Bioengineering
Moritz Buhl, Mark Staniford, Sebastian Lamping, Martin Körsgen, Heinrich F Arlinghaus, Ulrich Kynast, Bart Jan Ravoo
Nanoclays are nanomaterials with versatile adsorptive properties. This contribution describes the generation of micropatterns of a nanoclay ("laponite") on ammonium-terminated, self-assembled monolayers (SAMs) on glass and silicon. Microstructured immobilization of the laponite was performed using micromolding in capillaries (MIMIC). The immobilization was verified using contact angle goniometry, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and fluorescence microscopy...
April 6, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Elena F Boer, Hannah F Van Hollebeke, Michael D Shapiro
Variation in regional identity, patterning, and structure of epidermal appendages contributes to skin diversity among many vertebrate groups, and is perhaps most striking in birds. In pioneering work on epidermal appendage patterning, John Saunders and his contemporaries took advantage of epidermal appendage diversity within and among domestic chicken breeds to establish the importance of mesoderm-ectoderm signaling in determining skin patterning. Diversity in chickens and other domestic birds, including pigeons, is driving a new wave of research to dissect the molecular genetic basis of epidermal appendage patterning...
March 24, 2017: Developmental Biology
James J Faust, Wayne Christenson, Kyle Doudrick, Robert Ros, Tatiana P Ugarova
Implantation of synthetic material, including vascular grafts, pacemakers, etc. results in the foreign body reaction and the formation of multinucleated giant cells (MGCs) at the exterior surface of the implant. Despite the long-standing premise that fusion of mononucleated macrophages results in the formation of MGCs, to date, no published study has shown fusion in context with living specimens. This is due to the fact that optical-quality glass, which is required for the majority of live imaging techniques, does not promote macrophage fusion...
June 2017: Biomaterials
Oren Shaya, Udi Binshtok, Micha Hersch, Dmitri Rivkin, Sheila Weinreb, Liat Amir-Zilberstein, Bassma Khamaisi, Olya Oppenheim, Ravi A Desai, Richard J Goodyear, Guy P Richardson, Christopher S Chen, David Sprinzak
During development, cells undergo dramatic changes in their morphology. By affecting contact geometry, these morphological changes could influence cellular communication. However, it has remained unclear whether and how signaling depends on contact geometry. This question is particularly relevant for Notch signaling, which coordinates neighboring cell fates through direct cell-cell signaling. Using micropatterning with a receptor trans-endocytosis assay, we show that signaling between pairs of cells correlates with their contact area...
March 13, 2017: Developmental Cell
Ryan H Takahashi, Sheerin Shahidi-Latham, Susan Wong, Jae H Chang
The rate of enzyme degradation (kdeg) is an important input parameter for the prediction of clinical drug-drug-interactions (DDI) that result from mechanism-based inactivation or induction of cytochrome P450s. Currently, a large range of reported estimates for CYP3A4 enzyme degradation exists, and consequently, large uncertainty exists in steady-state predictions for DDI. In the current investigations, stable isotope labeled amino acids in culture (SILAC) was applied to a long-lived primary human hepatocyte culture, HepatoPac, to directly monitor the degradation of CYP3A4...
March 13, 2017: Drug Metabolism and Disposition: the Biological Fate of Chemicals
Yuli Wang, Dulan B Gunasekara, Mark I Reed, Matthew DiSalvo, Scott J Bultman, Christopher E Sims, Scott T Magness, Nancy L Allbritton
The human small intestinal epithelium possesses a distinct crypt-villus architecture and tissue polarity in which proliferative cells reside inside crypts while differentiated cells are localized to the villi. Indirect evidence has shown that the processes of differentiation and migration are driven in part by biochemical gradients of factors that specify the polarity of these cellular compartments; however, direct evidence for gradient-driven patterning of this in vivo architecture has been hampered by limitations of the in vitro systems available...
June 2017: Biomaterials
Quentin Michaudel, Veronika Kottisch, Brett P Fors
During the last 40 years, researchers investigating photoinitiated cationic polymerizations have delivered tremendous success in both industrial and academic settings. A myriad of photoinitiating systems have been developed, allowing for the polymerization of a broad array of monomers (e.g., epoxides, vinyl ethers, alkenes, cyclic ethers, and lactones) under practical, inexpensive, and environmentally benign conditions. More recently, owing to progress in photoredox catalysis, photocontrolled cationic polymerization has emerged as a means to precisely regulate polymer chain growth...
March 9, 2017: Angewandte Chemie
Peng Li, Yu Han, Wenxin Wang, Yanju Liu, Peng Jin, Jinsong Leng
Micro/nanophotonic structures that are capable of optical wave-front shaping are implemented in optical waveguides and passive optical devices to alter the phase of the light propagating through them. The beam division directions and beam power distribution depend on the design of the micro/nanostructures. The ultimate potential of advanced micro/nanophotonic structures is limited by their structurally rigid, functional singleness and not tunable against external impact. Here, we propose a thermally induced optical beam-power splitter concept based on a shape memory polystyrene film with programmable micropatterns...
March 9, 2017: Scientific Reports
Yu Qi, Hui Wang, Kai Wei, Ya Yang, Ru-Yue Zheng, Ick Soo Kim, Ke-Qin Zhang
The biological performance of artificial biomaterials is closely related to their structure characteristics. Cell adhesion, migration, proliferation, and differentiation are all strongly affected by the different scale structures of biomaterials. Silk fibroin (SF), extracted mainly from silkworms, has become a popular biomaterial due to its excellent biocompatibility, exceptional mechanical properties, tunable degradation, ease of processing, and sufficient supply. As a material with excellent processability, SF can be processed into various forms with different structures, including particulate, fiber, film, and three-dimensional (3D) porous scaffolds...
March 3, 2017: International Journal of Molecular Sciences
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