3. Uniform Microparticles
U.S. Patent 8,470,398 (June 25, 2013), “Method for Producing Single-Hole Hollow Polymer Microparticles,” Hiroshi Yamauchi, and Yasuyuki Yamada (Sekisui Chemical Co., Ltd., Osaka, Japan).
Microparticles on the order of microns are useful for lightweight structures, heat insulation, cushioning, and selective light absorption. However, these applications require very uniform microparticle sizes. Preparation by suspension polymerization is commonly used to prepare microparticles but adequate uniformity is difficult requiring elaborate classification processing. Yamauchi and Yamada produced single-hole hollow polymer particles with extremely uniform dimensions without need for special classification operations. A dispersion of swollen particles is prepared by mixing seed particles in water with an oil-soluble solvent. The seed particles absorb the oil-soluble solvent. A water soluble polymer and crosslinkable monomer is added to the suspension and precipitated onto the suspended swollen particles. The particles after curing are washed with water and the oil soluble solvent vaporized, The inner and outer diameters are extremely uniform. Particles with outer diameters range from 0.1 to 100 microns while the inner diameters range from 10 to 99% of the outer diameters.
Magnetic microspheres for use in fluorescence-based applications
Chandler and Bedre of Luminex Corporation, Texas, developed microspheres with fluorescent and magnetic properties including a core microsphere and a magnetic material coupled to a surface of the core microsphere. About 50% or less of the surface of the core microsphere is covered by the magnetic material. The microsphere also includes a polymer layer surrounding the magnetic material and the core microsphere. One population of microspheres configured to exhibit fluorescent and magnetic properties includes two or more subsets of microspheres. The two or more subsets of microspheres are configured to exhibit different fluorescent and/or magnetic properties. (RDC 10/16/2012)
Microsphere-based materials with predefined 3D spatial and temporal control of biomaterials, porosity and/or bioactive signals
Detamore et al of The University of Kansas, Kansas, developed a tissue engineering scaffold for growing cells linking biocompatible microspheres together to form a three-dimensional matrix. The matrix includes pores for growing cells. The biocompatible microspheres can include first and second sets of microspheres. The first set of microspheres can have a first characteristic, and a first predetermined spatial distribution with respect to the three-dimensional matrix. The second set of microspheres can have a second characteristic that is different from the first characteristic, and a second predetermined spatial distribution that is different from the first predetermined spatial distribution with respect to the three-dimensional matrix. The first and second characteristics can selected a composition, polymer, particle size, particle size distribution, type of bioactive agent, type of bioactive agent combination, bioactive agent concentration, amount of bioactive agent, rate of bioactive agent release, mechanical strength, flexibility, rigidity, color, radiotranslucency and radiopaqueness. (RDC 10/8/2012)
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Roger D. Corneliussen
Maro Polymer Links
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Copyright 2012 by Roger D. Corneliussen.
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** Date of latest addition; date of first entry is 10/8/2012.