Relevant bibliographies by topics / Polymer micro-beads

Academic literature on the topic 'Polymer micro-beads'

Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Polymer micro-beads"

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Debasis Nayak and Saravanan Kaliyaperumal. "Development and effect of drug release from simvastatin loaded sodium alginate micro beads." World Journal of Biology Pharmacy and Health Sciences 12, no. 3 (December 30, 2022): 348–58. http://dx.doi.org/10.30574/wjbphs.2022.12.3.0259.

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The objective of the present study was to prepare the microbeads of Simvastatin loaded with sodium alginate to provide control release of drug delivery system. So, the design of drug delivery system was to improve and enhance the bioavailability of drug. The Simvastatin loaded microbeads were prepared by the ionic gelation method using polymer such as sodium alginate as a natural substance. Simvastatin loaded sodium alginate microbeads were formulated by different cross linking agent like CaCl₂, BaCl₂, ZnCl₂ and FeCl₃ in different ratio. The microbeads were spherical, free flowing exhibited drug content uniformity and high drug encapsulation efficiency. The swelling and drug release behavior depends upon amount of cross linking agent used in the microbeads. This released the drug up to 24 hours where beads released the drug up to 6 hours. The FTIR analysis of drug, polymers and the optimized formulation indicated the compatibility of the drug with the polymers. The DSC studies confirmed the drug polymer interaction in the microspheres. The SEM studies influence the rate of drug release from the microbeads. The present study concludes that the swelling and In-vitro release behavior of Simvastatin loaded sodium alginate microbeads can be considered as a promising control release drug delivery system.
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Zourob, Mohammed, Stephan Mohr, Andrew G. Mayes, Alexandra Macaskill, Natalia Pérez-Moral, Peter R. Fielden, and Nicholas J. Goddard. "A micro-reactor for preparing uniform molecularly imprinted polymer beads." Lab on a Chip 6, no. 2 (2006): 296. http://dx.doi.org/10.1039/b513195b.

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Vakifahmetoglu, Cekdar, Marco Balliana, and Paolo Colombo. "Ceramic foams and micro-beads from emulsions of a preceramic polymer." Journal of the European Ceramic Society 31, no. 8 (July 2011): 1481–90. http://dx.doi.org/10.1016/j.jeurceramsoc.2011.02.012.

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Descamps, Lucie, Marie-Charlotte Audry, Jordyn Howard, Samir Mekkaoui, Clément Albin, David Barthelemy, Léa Payen, et al. "Self-Assembled Permanent Micro-Magnets in a Polymer-Based Microfluidic Device for Magnetic Cell Sorting." Cells 10, no. 7 (July 9, 2021): 1734. http://dx.doi.org/10.3390/cells10071734.

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Magnetophoresis-based microfluidic devices offer simple and reliable manipulation of micro-scale objects and provide a large panel of applications, from selective trapping to high-throughput sorting. However, the fabrication and integration of micro-scale magnets in microsystems involve complex and expensive processes. Here we report on an inexpensive and easy-to-handle fabrication process of micrometer-scale permanent magnets, based on the self-organization of NdFeB particles in a polymer matrix (polydimethylsiloxane, PDMS). A study of the inner structure by X-ray tomography revealed a chain-like organization of the particles leading to an array of hard magnetic microstructures with a mean diameter of 4 µm. The magnetic performance of the self-assembled micro-magnets was first estimated by COMSOL simulations. The micro-magnets were then integrated into a microfluidic device where they act as micro-traps. The magnetic forces exerted by the micro-magnets on superparamagnetic beads were measured by colloidal probe atomic force microscopy (AFM) and in operando in the microfluidic system. Forces as high as several nanonewtons were reached. Adding an external millimeter-sized magnet allowed target magnetization and the interaction range to be increased. Then, the integrated micro-magnets were used to study the magnetophoretic trapping efficiency of magnetic beads, providing efficiencies of 100% at 0.5 mL/h and 75% at 1 mL/h. Finally, the micro-magnets were implemented for cell sorting by performing white blood cell depletion.
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Croft, Charles F., M. Inês G. S. Almeida, and Spas D. Kolev. "Development of micro polymer inclusion beads (µPIBs) for the extraction of lanthanum." Separation and Purification Technology 285 (March 2022): 120342. http://dx.doi.org/10.1016/j.seppur.2021.120342.

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Sun, Kun, Junqi Chen, Hong Zhao, Weifeng Sun, Yinsheng Chen, and Zhongming Luo. "Dynamic Thermomechanical Analysis on Water Tree Resistance of Crosslinked Polyethylene." Materials 12, no. 5 (March 5, 2019): 746. http://dx.doi.org/10.3390/ma12050746.

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The water tree resistance of crosslinked polyethylene (XLPE) initiated by ultraviolet (UV) irradiation technique is investigated through a water blade electrode method, and the effects of the mechanism of UV irradiation crosslinking on inhibiting water tree growth are revealed with dynamic thermomechanical analysis (DMA). The accelerated water tree aging experiment shows that UV irradiation crosslinking inhibits the growth rate of water trees, and the water tree length and width is reduced with the increase of the crosslinking degree of XLPE. The DMA result demonstrates that the molecular activity of the amorphous phase in XLPE as represented by polyethylene β-relaxation is gradually intensified with the increase of the crosslinking reaction. Combined with the fatigue mechanism of water tree growth in semi-crystalline polymers, it is suggested that the UV irradiation crosslinking reaction can significantly improve the anti-water-tree performance of linear low-density polyethylene (LLDPE). The crosslinking bond in the amorphous phase of UV-photoinitiated crosslinking polyethylene can produce a large number of cross-connected polymer chains, by which the length of fiber is obviously increased, leading to an reduced force from the micro-water beads onto the crack tip and thus decreasing the rate of the material being destroyed by micro-water beads.
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Georgescu, Constantin, Lorena Deleanu, and Mihail Botan. "Dry sliding of composites with PBT matrix and micro glass beads on steel." Industrial Lubrication and Tribology 66, no. 3 (April 8, 2014): 424–33. http://dx.doi.org/10.1108/ilt-03-2012-0026.

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Purpose – This research aims to characterize the tribological behavior of polybutylene terephthalate (PBT) and PBT composites with micro glass beads (MGB) on steel, in dry conditions and on a block-on-ring tester, pointing out the influence of sliding distance and speed. The tribology of PBT and its composites is still in an early stage because this thermoplastic polyester requires accurate technological and thermal treatment. Design/methodology/approach – The composites were produced by ICEFS Savinesti Romania and contain PBT grade Crastin6130NC010 (as supplied by Du Pont), 0.5 […] 1.0 per cent (weight) Relamyd B-2Nf (polyamide grade produced by ICEFS, for a better dispersion of MGB), 1 per cent (weight) black carbon for technological and tribological reasons and different micro glass beads (MGB) concentrations (10.0 and 20.0 per cent weight). Tests were done for different sliding distances (2,500, 5,000 and 7,500 m) and speeds (0.5, 1.0 and 1.5 m/s) and a normal load of 5 N. Findings – The friction coefficient and the wear parameter (as mass loss of polymeric blocks) pointed out a good tribological behavior for these composites. Scanning electron microscope (SEM) images revealed particular aspects of PBT local transfer on steel. Also, 10 per cent MGB in PBT reduces wear, especially for longer distances (75,000 m) and higher speeds (0.5 and 0.75 m/s); the friction coefficient is only slightly increased up to 0.23, being less influenced by the speed and the sliding distance as compared to neat polymer. Originality/value – PBT and PBT composites could become challengers for replacing materials in applications similar to tested ones. Even the neat polymer exhibits a good tribological behavior. The composites have a lower sensibility to higher speeds and sliding distances for the applied load.
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Oya, Asao, and Naoto Kasahara. "Preparation of thin carbon fibers from phenol–formaldehyde polymer micro-beads dispersed in polyethylene matrix." Carbon 38, no. 8 (2000): 1141–44. http://dx.doi.org/10.1016/s0008-6223(99)00232-8.

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Moritsugu, Masaki, Tomonari Ogata, Seiji Kurihara, and Takamasa Nonaka. "Synthesis of Photo-Cross Linking Polymer Beads and Application for Micro Fabrication of Periodic Structure." Molecular Crystals and Liquid Crystals 443, no. 1 (December 2005): 117–26. http://dx.doi.org/10.1080/15421400500247334.

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Haimhoffer, Ádám, Alexandra Vas, Gabriella Árvai, Éva Fenyvesi, László Jicsinszky, István Budai, Attila Bényei, et al. "Investigation of the Drug Carrier Properties of Insoluble Cyclodextrin Polymer Microspheres." Biomolecules 12, no. 7 (July 2, 2022): 931. http://dx.doi.org/10.3390/biom12070931.

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The investigation of the usability of solid insoluble β-cyclodextrin polymers (βCDP) in micro-sized, controlled drug delivery systems has only recently attracted interest. Our aim was to form complexes with poorly soluble active pharmaceutical ingredients (APIs) with two types of βCDP for drug delivery applications. Solid insoluble cyclodextrin polymer of irregular shape (βCDPIS) and cyclodextrin microbeads (βCDPB) were used in the experiments. Morphology, surface area, size distribution and swelling capacity of carriers were investigated. We created complexes with two APIs, curcumin and estradiol, and applied powder X-ray diffraction, FTIR and thermal analysis (TGA/DSC) to prove the complexation. Finally, the dissolution, biocompatibility and permeation of APIs on Caco-2 cells were investigated. The size of the beads was larger than 100 µm, their shape was spherical and surfaces were smooth; while the βCDPIS particles were around 4 µm with irregular shape and surface. None of the polymers showed any cytotoxic effect on Caco-2 cells. Both carriers were able to extract curcumin and estradiol from aqueous solutions, and the dissolution test showed prolonged estradiol release. Caco-2 permeability tests were in accordance with the complexation abilities and dissolution of the complexes. This study offers useful data for further pharmaceutical applications of insoluble cyclodextrin polymers.
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Dissertations / Theses on the topic "Polymer micro-beads"

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Wang, Chi Ming, and 王智明. "Micro-size Porous Polymer Beads by using Two-steps Polymerization." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/49050916595779316080.

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碩士
中原大學
化學工程研究所
82
Micro-size monodisperse porous crosslinked styrene-divinyl benzene copolymer particles to be prepared by seeded emulsion polymerization was studied. Monodisperse polystyrene particles prepared by dispersion polymerization were swelled by diluents, monomer, crossinking agent and initiator firstly , then these swelled particles were polymerized into crosslinked polymer particles. Using solvent to extract these particles, monodisperse porous copolymer particles were obtained. The effects of molecular weight of seeds and kinds of diluents on the properties of particles were investigated. The less the molecular weights of the seeds, the more the porosity of the particles was. Using the good solvent as the diluent, the obtained particles are to have small pore diameters. However, using the poor solvent as the diluent will enchane the phase separation and structure inhomogeneity.
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Azhar, Umar. "Spectroscopic Imaging of Multiplex Bioassays Encoded by Raman and SERS Tags." Thesis, 2019. http://hdl.handle.net/2440/120461.

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Suspension microsphere multiplex immunoassays are rapidly gaining recognition in immunoglobulin G (IgG) identification. Detection of multiple analytes from a single sample is critical in modern bioanalytical technique, which always requires complex encoding. However, traditional fluorescent technology has various limitations in such multiplex encoding systems. The aim of this study is to use Raman and surface enhanced Raman scattering (SERS) signatures as novel encoding elements in immunoassays to overcome various problems associated with fluorescence labels. In addition to the amplified capacity of Raman/SERS encoding elements, the use of Raman imaging aimed at reinforcement of qualitative analysis has been demonstrated for the first time. This holds great promise in biomedical applications. In this thesis, a series of IgGs were selected as model proteins, and gold nanoparticles (AuNPs) served as the “hotspot” of SERS-active substrates. Three different Raman-active molecules namely, 4-aminothiophenol (4-ATP), 4-mercaptobenzoic acid (4-MBA), and 3- mercaptopropionic acid (3-MPA) can be easily self-assembled on the AuNPs to form functional SERS tags. Various polymer microbeads (prepared by dispersion polymerization) were utilized as the immune-solid supports together with providing Raman signatures. Additionally, focus was laid on the fabrication of different SERS nanotags and Raman spectroscopic-encoded polymer microbeads for the multiplex, specific and selective detection of biomarkers in dual encoded immunoassay systems. Raman imaging of different uniform polymer microbeads were evaluated. Polymers are long chain molecules containing many repeating monomer units, which give rise to the strong Raman signals of these monomers. In addition, different monomers can be polymerised together to produce co-polymer microbeads to provide different Raman signatures. The development of polymer microbeads not only improves the detection sensitivity significantly, but also makes these microbeads to be more multiplexed in lieu of specific post-reaction labelling. Four Raman spectroscopic-encoded copolymer microbeads were fabricated by dispersion polymerization with their average diameters of 1.1 to 1.7 μm. These synthesised microbeads namely, poly(Sty-co-AA), poly(4tBS-co-AA), poly(4MS-co-AA) and poly(GMAco- AA) revealed narrow size distribution and unique Raman fingerprints, which rendered them to be suitable for Raman imaging and immunoassay analysis. Furthermore, microbeads combining the Raman and SERS signals were successfully fabricated by conjugating a SERS nanotag (4-ATP on the surface of AuNPs) to two Raman encoded polymer microbeads of poly(Sty-co-AA) and poly(4tBS-co-AA). The spectroscopic and imaging results reinforce the suitability of such dual coding systems for immunoassays, which further expands the possibility of Raman/SERS multiplex systems for biological analysis. Finally, a practical demonstration of multiplex IgG immunoassay system based on carboxylated Raman encoded polymer microbeads and SERS nanotags was developed. Antibodies (donkey anti-goat IgG & donkey anti-rabbit IgG) were conjugated to polymer microbeads by EDC coupling chemistry. Two different batches of SERS nanotags comprising of Raman-active molecules (4-MBA & 3-MPA) with AuNPs were synthesised. Moreover, antigens (goat anti-human IgG and rabbit anti-human IgG) were conjugated on SERS tags to form SERS reporters. The immunoassays were performed by mixing the protein conjugated polymer microbeads and SERS reporters. Due to the specific recognition between antibody and antigen, SERS nanotags attached on the surface of their specific antibody polymer microbeads. The results were positively verified from both Raman imaging and spectroscopic analysis. In summary, a series of SERS nanotags and Raman spectroscopic-encoded copolymer microbeads were successfully synthesised. The thesis further demonstrates Raman imaging analysis as a new strategy for qualitative analysis of complicated multiplex immunoassay with high sensitivity and specificity.
Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering & Advanced Materials, 2019
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Books on the topic "Polymer micro-beads"

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Nussinovitch, Amos. Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6.

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Nussinovitch, A. Polymer macro- and micro-gel beads: Fundamentals and applications. New York: Springer, 2010.

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Nussinovitch, Amos. Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications. Springer, 2010.

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Nussinovitch, Amos. Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications. Springer, 2014.

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Book chapters on the topic "Polymer micro-beads"

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Nussinovitch, Amos. "Beads for Environmental Applications." In Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 255–78. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6_10.

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Nussinovitch, Amos. "Beads as Drug Carriers." In Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 191–230. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6_8.

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Nussinovitch, Amos. "Medicinal Applications of Hydrocolloid Beads." In Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 117–36. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6_5.

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Nussinovitch, Amos. "Physical Properties of Beads and Their Estimation." In Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 1–25. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6_1.

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Nussinovitch, Amos. "Beads and Special Applications of Polymers for Agricultural Uses." In Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 231–53. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6_9.

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Nussinovitch, Amos. "Food and Biotechnological Applications for Polymeric Beads and Carriers." In Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 75–116. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6_4.

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Nussinovitch, Amos. "Methods and Mathematical Models for the Drying of Polymeric Beads." In Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 53–74. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6_3.

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Nussinovitch, Amos. "Bead Formation, Strengthening, and Modification." In Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 27–52. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6_2.

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Nussinovitch, Amos. "Dry Bead Formation, Structure, Properties, and Applications." In Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 137–62. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6_6.

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Nussinovitch, Amos. "Liquid-Core Beads and Their Applications in Food, Biotechnology, and Other Fields." In Polymer Macro- and Micro-Gel Beads: Fundamentals and Applications, 163–89. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6618-6_7.

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Conference papers on the topic "Polymer micro-beads"

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Kudtarkar, Kaushik A., Thomas W. Smith, Patricia Iglesias, and Michael J. Schertzer. "Microfluidic Synthesis of Polymer Ionic Liquid Gel Beads for Energy Harvesting Applications." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67018.

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In the operation of many common devices and processes, more than 60% of consumed energy is wasted in many common processes. These loses come in many forms including heat, friction, and vibration. Energy harvesters are devices that can recapture some of this waste energy and convert it into electrical energy. This work will focus on electrostatic energy harvesting devices that recapture vibrational energy. Electrostatic energy harvesters recapture mechanical energy when a conductive mass translates or deforms in an electric field. Polymer ionic liquid gel beads may serve as a useful replacement for fluid droplets in electrostatic energy harvesters. This work uses a recently developed method for reliable synthesis of polymer gel beads. These beads are synthesized using a micro-reactor, which generates monomeric droplets in a silicon oil carrier fluid. The monomer solution also contains a photoinitiator and cross linker, which enables the monomer to polymerize when exposed to UV light. The present work demonstrates a method to rapidly synthesize uniform beads with a variety of chemical compositions. These chemical compositions can be used to tune the electromechanical properties of the beads to improve performance in applications such as energy harvesting devices.
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Kingsley, David M., Andrew D. Dias, Douglas B. Chrisey, and David T. Corr. "A Novel, Laser-Based Technique to Fabricate and Precisely Pattern Cell-Encapsulated Alginate Microbeads." In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14658.

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Microbeads are three-dimensional, generally spherical microstructures that are currently being investigated for applications in tissue engineering and for delivery of drugs, proteins, and DNA [1, 2]. Current microbead fabrication devices such as electrostatic bead generators, microfluidic devices, and micro-vibrators, function by using cross-linkable polymers into a crosslinking solution, such as calcium chloride in the case of alginate. These procedures allow for the controlled manipulation of microbead size, e.g., increasing electric field voltage for the electrostatic bead generator during polymer extrusion. Popular devices such as electrostatic bead generators are limited to polyelectrolyte materials because of the electric field extrusion method [3]. In addition, despite their ability to create monodispersed beads of different size, none of these technologies can precisely control microbead placement.
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Yamakawa, Takeshi, Akihiro Maruyama, Hirohisa Uedan, Takanori Iino, and Yoichiroh Hosokawa. "Experimental and calculative estimation of femtosecond laser induced-impulsive force in culture medium solution with motion analysis of polymer micro-beads." In SPIE LASE, edited by Stephan Roth, Yoshiki Nakata, Beat Neuenschwander, and Xianfan Xu. SPIE, 2015. http://dx.doi.org/10.1117/12.2077403.

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Cole, Daniel P., and Ed M. Habtour. "Improved Understanding of Damage Precursors Through Local Mechanical Characterization." In ASME 2015 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/smasis2015-8822.

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We report on the use of local mechanical characterization techniques for the understanding of structural damage precursors in various material systems. Instrumented indentation and atomic force microscopy (AFM) were used to characterize local damage in: (1) fatigued metallic beams subject to non-linear vibration, (2) individual polymer and glass microfibers, and (3) additive manufactured thermoplastics. Indentation studies of the fatigued metallic beams showed a compliance effect of up to 40% in relatively highly stressed regions. An approved fiber mounting technique allowed for indentation of unmodified surfaces of single microfibers, while AFM modulus maps of the fibers reveal local regions of relative compliance. Local mechanical tests of 3-D printed acrylonitrile butadiene styrene specimens revealed a variation in properties between printed beads and bead-bead interfaces. The nano-/micro-scale techniques developed in the present study provide a framework for understanding how damage precursors may affect processing-structure-property relationships in present and future structural aerospace materials.
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Lee, Doh-Hyoung, Jonghyun Oh, Robert Hart, Bakhtier Farouk, and Hongseok Moses Noh. "A Study of AC Electrokinetic Phenomena Under DC Electroosmotic Flows." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68969.

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AC electrokinetic phenomena have drawn much attention in the microfluidics and lab-on-a-chip communities since these techniques have a great potential for effective manipulation of small particles (micro- to nanoscale particles, polymer beads to biological cells and molecules) and fluids in microchannel environments. One unanswered question is how the AC electrokinetic phenomena are affected by DC electroosmotic flows that are often employed in lab-on-a-chip systems as a pumping method. This paper presents experimental and numerical studies on the interaction between AC electrokinetic phenomena and DC electroosmotic flows. The motions of polystyrene microbeads suspended in deionized water in a microchannel were studied as the main AC and DC electrokinetics parameters were varied. Numerical simulations of flow field were performed using COMSOL Multiphysics software. The forces considered in the numerical simulation include electrophoresis, DC electroosmosis, dielectrophoresis, AC electroosmosis, electrothermal effect, diffusion, Stokes drag force, and gravity. The numerical simulation results showed good agreements with experimental data. We believe that this study will contribute to the understanding of the interactions between DC and AC electrokinetic phenomena and thus enable researchers to develop powerful microdevices based on the combination of these two techniques.
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Dharmatilleke, Saman, C. A. Wijayawardhana, N. Okulan, P. Medis, J. H. Thomas, H. Thurman Henderson, William R. Heineman, and H. Brian Halsall. "A Hybrid Microfluidic Mini System Towards a “Lab-on-a-Chip” for Biochemical Immunoassay." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1123.

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Abstract Hand-held, fully automated microfluidic systems have been developed and characterized to perform a magnetic bead-based biochemical immunoassay. The magnetic beads were coated with a polymer on which a dendritic antibody had been prepared to form the basis of a “sandwich” immunoassay for sensing biomolecules. With the press of a button, a complete immunoassay is performed to detect biohazards, and the result of the assay is displayed on a LCD. One system was made by using biocompatible silicone tubing for interconnections between the devices while another system was fabricated on a micromachined “glass-on-silicon” motherboard (Dharmatilleke et al.,. 2000). The first system consists of four collapsible reservoirs for reagent storage, made of very thin biocompatible Teflon™; an array of zero dead volume pinch valves; two magnetic curtain magnetic particle separators; a micro wire electrode or IDA for detection; a flow sensor, a valveless rotary pump to pull the reagents through the microfluidic system and associated electronics. On the second system, the mini pinch valves have been replaced by “collapsible” membrane type zero dead volume valves and pumping is by peristaltic operation of the valves. This work preceeds the next step, which is an all-MEMS system “on-a-chip”.
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Du, Xuemin, Juan Wang, Huanqing Cui, Qilong Zhao, and Yumei Hu. "Fabrication of inverse opal beads based on biocompatible and biodegradable polymer." In 2017 IEEE 12th International Conference on Nano/Micro Engineered and Molecular Systems (NEMS). IEEE, 2017. http://dx.doi.org/10.1109/nems.2017.8017117.

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Monneret, Serge, Federico Belloni, and Olivier Soppera. "Complex Three-Dimensional Fluidic Reservoirs to Control Beads/Living Cells Contacts." In ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2006. http://dx.doi.org/10.1115/icnmm2006-96167.

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In this paper, we combine holographic multiple optical tweezers with a three-dimensional microfluidic system to create a versatile microlaboratory. In order to determine cells local and/or temporal response to stimuli, and therefore draw their map of sensitivity, one convenient way is to apply antigen-covered latex beads in order to bind to plasma membrane, by means of optical tweezers. Using multiple optical traps could improve the efficiency of the measurements, but also their versatility. Therefore, we have developed a complete system based on holographic optical tweezers to realise multiple-point interactions between beads and cells with control of the stimulation places, timing, and durations. As we plan to use our system to study biological events in the hour timescale, we have to keep beads and cells separated, in order to prevent unwanted beads to circulate freely in the sample and bind to the target cell during the experiment. We then introduced microstereolithography as a 3D micro-manufacturing approach to the rapid prototyping of three-dimensional fluidic microchambers of complex shapes inside the sample, comprising wells, channels and walls to inject beads locally and keep them separated from cells in our assays. We demonstrated the possibility for microSL to easily and rapidly (typically one hour) fabricate small and three-dimensional observation chambers with customized design of the flow channels, including fluidic reservoirs of typically 500–1500 μm diameter, 5–12 mm height, in order to facilitate manual filling. Several shapes of reservoirs designed to keep beads and cells separated in liquid samples have been realized and successfully tested. Some of them included up to 3 reservoirs, in order to allow co-distribution of different types of beads. Each reservoir typically contained 2–10 μl of solution holding the beads, with a horizontal outlet of 100–200 μm in diameter which allows beads to deposit locally on the microscope cover glass placed under the reservoir outlet. Limited extension of beads under the outlet on the glass has been confirmed, and the ability of the polymeric structures to confine beads in a restricted area has been demonstrated. In the following we present examples of manipulations by multiple holographic optical tweezers consisting at first in extracting several beads from such an area by going through an aperture designed in the structure, making them travel to the target cell, and finally depositing on its outer membrane.
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Gangadharan, Kishore, Conrad James, Hongjun Song, and Dawn J. Bennett. "Manipulation of Biological Analytes in Microfluidic Devices Using Various Electrode Geometries and Electrokinetic Techniques." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43544.

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Abstract:
Micro-electro-mechanical systems are now used in a wide variety of applications ranging from biodetection to the healthcare industry. Electrokinetic techniques such as dielectrophoresis and electroosmosis are frequently used for the manipulation of cells, molecules, and spores. In this paper, we show that dielectrophoresis can be used to manipulate allergens and bacteria in a wide variety of microfluidic devices. We have found that allergens such as Penicillium brevicompactum demonstrate positive dielectrophoresis and moves toward high field gradient regions while the non-biological latex beads move towards the low electric field gradient regions. Microfluidic devices equipped with dielectrophoretic gates arranged perpendicular to the flow were designed and fabricated at Sandia National Laboratories. Experiments were conducted on flowing suspensions over a broad range of flow and electric field parameters to investigate how these characteristics affect the concentration and separation of particles. Trapping using the dielectrophoretic gating device as well as the design, experimental results, and analysis of devices for particle filtration are presented. Some of the devices were fabricated using Sandia’s (SwIFT™) process while other devices were fabricated using polymers and traditional photolithography methods. We present both methods used in the fabrication of devices. The long-term goal is to develop complete hand held Lab-on-a-Chip microsystems for biodetection. The ability to manipulate and concentrate minute particles can allow for advances in the medical field as well as the future detection of biological warfare agents such as anthrax. In order to analyze biological analytes, it is first necessary to develop a method for positioning and detecting the analyte of interest. Concentrating biological particles such as the allergen Penicillium brevicompactum (PBC), Bacillus globigii (BG) spores, an anthrax stimulant, and Staphylococcus Aureus (Staph Cells), a type of food bacteria, is done using the principle of dielectrophoresis. Microfluidic devices which we use to test the suspensions were fabricated using the SwIFT™ process developed by Sandia National Laboratories. In addition, electrode designs were also fabricated using a process that we have developed in-house at the University of Maryland Baltimore County (UMBC) using polydimethysiloxane, PDMS, to make the channels and the deposition of gold, Au, as the material for the electrodes fabricated with the low pressure chemical vapor deposition method (LPCVD).
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