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https://www.readbyqxmd.com/read/29352711/gold-cleaning-methods-for-preparation-of-cell-culture-surfaces-for-self-assembled-monolayers-of-zwitterionic-oligopeptides
#1
Junko Enomoto, Tatsuto Kageyama, Dina Myasnikova, Kisaki Onishi, Yuka Kobayashi, Yoko Taruno, Takahiro Kanai, Junji Fukuda
Self-assembled monolayers (SAMs) have been used to elucidate interactions between cells and material surface chemistry. Gold surfaces modified with oligopeptide SAMs exhibit several unique characteristics, such as cell-repulsive surfaces, micropatterns of cell adhesion and non-adhesion regions for control over cell microenvironments, and dynamic release of cells upon external stimuli under culture conditions. However, basic procedures for the preparation of oligopeptide SAMs, including appropriate cleaning methods of the gold surface before modification, have not been fully established...
January 15, 2018: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/29352710/changes-in-hepg2-spheroid-behavior-induced-by-differences-in-the-gap-distance-between-spheroids-in-a-micropatterned-culture-system
#2
Daisuke Miyamoto, Takuya Hara, Ai Hyakutake, Kohji Nakazawa
Micropatterning is a promising technique for modulating culture environments. In this study, we investigated the effect of spheroid separation distance on their properties in a micropatterned chip of HepG2 spheroids. The basic chip design consisted of 37 collagen spots (300 μm in diameter) in a hexagonal arrangement on a glass substrate; the region without collagen-spots was modified by polyethylene glycol to create the non-adhesive surface. Three similar chips were fabricated with gap distances between collagen-spots of 500, 1000, and 1500 μm...
January 15, 2018: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/29350833/platelets-kill-bacteria-by-bridging-innate-and-adaptive-immunity-via-pf4-and-fc%C3%AE-riia
#3
R Palankar, T P Kohler, K Krauel, J Wesche, S Hammerschmidt, A Greinacher
BACKGROUND: Activated platelets release the chemokine platelet factor 4 (PF4) stored in their granules. PF4 binds to polyanions (P) on bacteria, undergoes a conformational change and exposes neoepitopes. These neoepitopes induce production of anti-PF4/P antibodies. As PF4 binds to a variety of bacteria, anti-PF4/P IgG can bind and opsonize several bacterial species. OBJECTIVE: Here we investigated whether platelets are able to kill bacteria directly after recognizing anti-PF4/P IgG opsonized bacteria in the presence of PF4 via their FcγRIIA...
January 19, 2018: Journal of Thrombosis and Haemostasis: JTH
https://www.readbyqxmd.com/read/29345707/synthesis-and-characterization-of-a-photocleavable-collagen-like-peptide
#4
Alfredo Ornelas, Kaitlyn N Williams, Kevin A Hatch, Aurelio Paez, Angela C Aguilar, Cameron C Ellis, Nishat Tasnim, Supriyo Ray, Carl W Dirk, Thomas Boland, Binata Joddar, Chunqiang Li, Katja Michael
A 34-amino acid long collagen-like peptide rich in proline, hydroxyproline, and glycine, and with four photoreactive N-acyl-7-nitroindoline units incorporated into the peptide backbone was synthesized by on-resin fragment condensation. Its circular dichroism supports a stable triple helix structure. The built-in photochemical function enables the decomposition of the peptide into small peptide fragments by illumination with UV light of 350 nm in aqueous solution. Illumination of a thin film of the peptide, or a thin film of a photoreactive amino acid model compound containing a 5-bromo-7-nitroindoline moiety, with femtosecond laser light at 710 nm allows for the creation of well-resolved micropatterns...
January 18, 2018: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/29337695/automated-fabrication-of-photopatterned-gelatin-hydrogels-for-organ-on-chips-applications
#5
Janna C Nawroth, Lisa L Scudder, Ryan T Halvorson, Jason Tresback, John P Ferrier, Sean P Sheehy, Alex Cho, Suraj Kannan, Ilona Sunyovszki, Josue A Goss, Patrick H Campbell, Kevin Kit Parker
Organ-on-chip platforms aim to improve preclinical models for organ-level responses to novel drug compounds. Heart-on-a-chip assays in particular require tissue engineering techniques that rely on labor-intensive photolithographic fabrication or resolution-limited 3D printing of micropatterned substrates, which limits turnover and flexibility of prototyping. We present a rapid and automated method for large scale on-demand micropatterning of gelatin hydrogels for organ-on-chip applications using a novel biocompatible laser-etching approach...
January 16, 2018: Biofabrication
https://www.readbyqxmd.com/read/29337076/opposing-kinesin-and-myosin-i-motors-drive-membrane-deformation-and-tubulation-along-engineered-cytoskeletal-networks
#6
Betsy B McIntosh, Serapion Pyrpassopoulos, Erika L F Holzbaur, E Michael Ostap
Microtubule and actin filament molecular motors such as kinesin-1 and myosin-Ic (Myo1c) transport and remodel membrane-bound vesicles; however, it is unclear how they coordinate to accomplish these tasks. We introduced kinesin-1- and Myo1c-bound giant unilamellar vesicles (GUVs) into a micropatterned in vitro cytoskeletal matrix modeled after the subcellular architecture where vesicular sorting and membrane remodeling are observed. This array was composed of sparse microtubules intersecting regions dense with actin filaments, and revealed that Myo1c-dependent tethering of GUVs enabled kinesin-1-driven membrane deformation and tubulation...
January 9, 2018: Current Biology: CB
https://www.readbyqxmd.com/read/29327436/effect-of-patterned-electrospun-hierarchical-structures-on-alignment-and-differentiation-of-mesenchymal-stem-cells-biomimicking-bone
#7
Sharanya Sankar, Manohar Kakunuri, Sindhuja D E, Chandra S Sharma, Subha N Rath
Considering the complex hierarchical structure of bone, biomimicking the micro and nano level features should be an integral part of scaffold fabrication for successful bone regeneration. We aim to biomimic the micro- and nano-structure of bone and study the effect of physical cues on cell alignment, proliferation and differentiation. To achieve this, we have divided the scaffolds into groups: electrospun SU-8 nanofibers, electrospun SU-8 nanofibers with UV treatment and micropatterned (20 μm sized ridges and grooves) SU-8 nanofibers by photolithography with UV treatment...
January 11, 2018: Journal of Tissue Engineering and Regenerative Medicine
https://www.readbyqxmd.com/read/29323433/electrically-driven-microengineered-bioinspired-soft-robots
#8
Su Ryon Shin, Bianca Migliori, Beatrice Miccoli, Yi-Chen Li, Pooria Mostafalu, Jungmok Seo, Serena Mandla, Alessandro Enrico, Silvia Antona, Ram Sabarish, Ting Zheng, Lorenzo Pirrami, Kaizhen Zhang, Yu Shrike Zhang, Kai-Tak Wan, Danilo Demarchi, Mehmet R Dokmeci, Ali Khademhosseini
To create life-like movements, living muscle actuator technologies have borrowed inspiration from biomimetic concepts in developing bioinspired robots. Here, the development of a bioinspired soft robotics system, with integrated self-actuating cardiac muscles on a hierarchically structured scaffold with flexible gold microelectrodes is reported. Inspired by the movement of living organisms, a batoid-fish-shaped substrate is designed and reported, which is composed of two micropatterned hydrogel layers. The first layer is a poly(ethylene glycol) hydrogel substrate, which provides a mechanically stable structure for the robot, followed by a layer of gelatin methacryloyl embedded with carbon nanotubes, which serves as a cell culture substrate, to create the actuation component for the soft body robot...
January 11, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29316156/tailored-environments-to-study-motile-cells-and-pathogens
#9
REVIEW
Julianne Mendi Muthinja, Johanna Ripp, Timothy Krüger, Andrea Imle, Tamás Haraszti, Oliver T Fackler, Joachim P Spatz, Markus Engstler, Friedrich Frischknecht
Motile cells and pathogens migrate in complex environments and yet are mostly studied on simple 2D substrates. In order to mimic the diverse environments of motile cells a set of assays including substrates of defined elasticity, microfluidics, micropatterns, organotypic cultures and 3D gels have been developed. We briefly introduce these and then focus on the use of micro-patterned pillar arrays, which help to bridge the gap between 2D and 3D. These structures are made from polydimethylsiloxane, a moldable plastic and their use has revealed new insights into mechanoperception in Caenorhabditis elegans, gliding motility of Plasmodium, swimming of trypanosomes and nuclear stability in cancer cells...
January 7, 2018: Cellular Microbiology
https://www.readbyqxmd.com/read/29314825/mixed-copolymer-adlayers-allowing-reversible-thermal-control-of-single-cell-aspect-ratio
#10
Fabrice Dalier, Galina V Dubacheva, Marie Coniel, Drazen Zanchi, Anouk Galtayries, Matthieu Piel, Emmanuelle Marie, Christophe Tribet
Dynamic guidance of living cells is achieved by fine tuning and spatiotemporal modulation on artificial polymer layers enabling reversible peptide display. Adjustment of surface composition and interactions is obtained by coadsorption of mixed poly(lysine) derivatives, grafted with either repellent PEG, RGD adhesion peptides, or T-responsive poly(N-isopropylacrylamide) strands. Deposition of mixed adlayers provides a straightforward mean to optimize complex substrates, which is here implemented to achieve 1) thermal control of ligand accessibility and 2) adjustment of relative adhesiveness between adjacent micropatterns, while preserving cell attachment during thermal cycles...
January 9, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29304548/protein-substrate-adhesion-in-microcontact-printing-regulates-cell-behaviors
#11
Shuhuan Hu, Ting-Hsuan Chen, Yanhua Zhao, Zuankai Wang, Raymond H W Lam
Microcontact printing (μCP) is widely used to create patterns of biomolecules essential for studies of cell mechanics, migration, and tissue engineering. However, different types of μCPs may create micropatterns with varied protein-substrate adhesion, which may change cell behaviors and pose uncertainty in result interpretation. Here, we characterize two μCP methods for coating extracellular matrix (ECM) proteins (stamp-off and covalent-bond) and demonstrate for the first time the important role of protein-substrate adhesion in determining cell behaviors...
January 5, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29302968/writing-wrinkles-on-polydimethylsiloxane-pdms-by-surface-oxidation-with-a-co2-laser-engraver
#12
Lin Qi, Cody Ruck, Griffin Spychalski, Brian King, Benxin Wu, Yi Zhao
Surface wrinkles formed by the buckling of a strained stiff layer attached to a soft elastomer foundation has been widely used in a variety of applications. Micropatterning of wrinkled topographies is, however, limited by process/system complexities. In this paper, we report an approach to write surface wrinkles with desired pattern geometries on polydimethylsiloxane (PDMS) elastomers using a commercial infrared laser engraver with the spot size of 127 μm. Wrinkled micropatterns with the wavelength from < 50 μm to > 300 μm were obtained in minutes without using special facilities or atmospheres...
January 5, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29298336/controlling-cell-shape-on-hydrogels-using-lift-off-protein-patterning
#13
Jens Moeller, Aleksandra K Denisin, Joo Yong Sim, Robin E Wilson, Alexandre J S Ribeiro, Beth L Pruitt
Polyacrylamide gels functionalized with extracellular matrix proteins are commonly used as cell culture platforms to evaluate the combined effects of extracellular matrix composition, cell geometry and substrate rigidity on cell physiology. For this purpose, protein transfer onto the surface of polyacrylamide hydrogels must result in geometrically well-resolved micropatterns with homogeneous protein distribution. Yet the outcomes of micropatterning methods have not been pairwise evaluated against these criteria...
2018: PloS One
https://www.readbyqxmd.com/read/29283550/spatiotemporal-characteristics-of-intercellular-calcium-waves-communication-in-micropatterned-assemblies-of-single-cells
#14
Fulin Xing, Ping Zhang, Pengchong Jiang, Ziyuan Chen, Jianyu Yang, Fen Hu, Irena Drevenšek-Olenik, Xinzheng Zhang, Leiting Pan, Jingjun Xu
Micropatterned substrates offer a unique possibility to define and control spatial organization of biological cells at the microscale, which greatly facilitates investigations of the cell-to-cell communication in vitro. Here, we developed a simple micropatterning strategy to resolve various spatiotemporal characteristics of intercellular calcium waves (ICWs) communication among isolated BV-2 microglial cells. By using a single ring assembly, we found that the direction of the initial transmitter secretion was strongly correlated with the site of the cell at which the mechanical stimulus triggering the ICWs was imposed...
December 28, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29280350/emerging-biotechnology-applications-of-aqueous-two-phase-systems
#15
REVIEW
Alyne G Teixeira, Rishima Agarwal, Kristin Robin Ko, Jessica Grant-Burt, Brendan M Leung, John P Frampton
Liquid-liquid phase separation between aqueous solutions containing two incompatible polymers, a polymer and a salt, or a polymer and a surfactant, has been exploited for a wide variety of biotechnology applications throughout the years. While many applications for aqueous two-phase systems fall within the realm of separation science, the ability to partition many different materials within these systems, coupled with recent advances in materials science and liquid handling, has allowed bioengineers to imagine new applications...
December 27, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/29258232/a-micro-pressure-sensing-method-based-on-the-micropatterned-electrodes-filled-with-the-microspheres
#16
Jianli Cui, Binzhen Zhang, Junping Duan, Hao Guo, Jun Tang
As the core component of the sense of touch, flexible pressure sensors are critical to synchronized interactions with the surrounding environment. Here, we introduce a new type of flexible capacitive pressure sensor based on a template of electrodes, with a one-dimensional pyramid micropatterned structure on a Polydimethylsiloxane (PDMS) substrate and a dielectric layer of polystyrene (PS) microspheres. The proposed sensor exhibits a stable and high sensing sensitivity of 0.741 kPa-1 to capacitance, good durability over 1000 cycles, and fast response time (<150 ms)...
December 18, 2017: Materials
https://www.readbyqxmd.com/read/29245781/versatile-and-scalable-micropatterns-on-graphene-oxide-films-based-on-laser-induced-fluorescence-quenching-effect
#17
Zhixing Qiao, Chengbing Qin, Wenjun He, Yani Gong, Guofeng Zhang, Ruiyun Chen, Yan Gao, Liantuan Xiao, Suotang Jia
Here we report on the preparation of quasi-homogeneous fluorescence emission from graphene oxide (GO) film by modifying the local optical properties through the laser-induced fluorescence quenching effect, and the fabrication of single and multilayer micropatterns on quasi-homogeneous GO films. The modification is stemming from the photoreduction of GO, where the reduction degree and fluorescence intensity can be precisely tuned by changing the laser power and irradiation duration. This versatile approach with a mask-free feature can be readily used to fabricate various complex microstructures on quasi-homogeneous GO film from single layer to multilayer in vertical scale, as well as micrometers to centimeters in lateral scale...
December 11, 2017: Optics Express
https://www.readbyqxmd.com/read/29242860/aluminum-nanostructures-with-strong-visible-range-sers-activity-for-versatile-micropatterning-of-molecular-security-labels
#18
Chee Leng Lay, Charlynn Sher Lin Koh, Jing Wang, Yih Hong Lee, Ruibin Jiang, Yijie Yang, Zhe Yang, In Yee Phang, Xing Yi Ling
The application of aluminum (Al)-based nanostructures for visible-range plasmonics, especially for surface-enhanced Raman scattering (SERS), currently suffers from inconsistent local electromagnetic field distributions and/or inhomogeneous distribution of probe molecules. Herein, we lithographically fabricate structurally uniform Al nanostructures which enable homogeneous adsorption of various probe molecules. Individual Al nanostructures exhibit strong local electromagnetic field enhancements, in turn leading to intense SERS activity...
December 15, 2017: Nanoscale
https://www.readbyqxmd.com/read/29227456/photopolymerized-microfeatures-guide-adult-spiral-ganglion-and-dorsal-root-ganglion-neurite-growth
#19
Linjing Xu, Alison E Seline, Braden Leigh, Mark Ramirez, C Allan Guymon, Marlan R Hansen
HYPOTHESIS: Microtopographical patterns generated by photopolymerization of methacrylate polymer systems will direct growth of neurites from adult neurons, including spiral ganglion neurons (SGNs). BACKGROUND: Cochlear implants (CIs) provide hearing perception to patients with severe to profound hearing loss. However, their ability to encode complex auditory stimuli is limited due, in part, to poor spatial resolution caused by spread of the electrical currents in the inner ear...
January 2018: Otology & Neurotology
https://www.readbyqxmd.com/read/29225769/fabrication-of-low-cost-micropatterned-polydimethyl-siloxane-scaffolds-to-organise-cells-in-a-variety-of-two-dimensioanl-biomimetic-arrangements-for-lab-on-chip-culture-platforms
#20
Lidia Escutia-Guadarrama, Genaro Vázquez-Victorio, David Martínez-Pastor, Brenda Nieto-Rivera, Marcela Sosa-Garrocho, Marina Macías-Silva, Mathieu Hautefeuille
We present the rapid-prototyping of type I collagen micropatterns on poly-dimethylsiloxane substrates for the biomimetic confinement of cells using the combination of a surface oxidation treatment and 3-aminopropyl triethoxysilane silanisation followed by glutaraldehyde crosslinking. The aim of surface treatment is to stabilise microcontact printing transfer of this natural extracellular matrix protein that usually wears out easily from poly-dimethylsiloxane, which is not suitable for biomimetic cell culture platforms and lab-on-chip applications...
January 2017: Journal of Tissue Engineering
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