Patents by Inventor Peter X. Ma
Peter X. Ma has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8445588Abstract: A water soluble copolymer includes first and second hydrophilic block segments or graft chains. The first hydrophilic block segment or graft chain contains cyclodextrin groups in at least a majority of its repeating units, and the second hydrophilic block segment or graft chain contains repeating units other than cyclodextrin groups. The first and second block segments or graft chains are covalently linked.Type: GrantFiled: August 18, 2009Date of Patent: May 21, 2013Assignee: The Regents of The University of MichiganInventors: Peter X. Ma, Jianxiang Zhang
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Publication number: 20120308825Abstract: Nano-fibrous microspheres and methods for forming them are disclosed herein. In one embodiment the microsphere includes a plurality of nano-fibers aggregated together in a spherical shape; and a plurality of pores formed between at least some of the plurality of nano-fibers. The nano-fibers are formed of star-shaped polymers.Type: ApplicationFiled: February 9, 2011Publication date: December 6, 2012Inventors: Peter X. Ma, Xiaohua Liu
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Publication number: 20120301516Abstract: Porous materials and methods for forming them are disclosed. One method for immobilizing micro-particles and/or nano-particles onto internal pore surfaces and/or external pore surfaces of porous materials includes suspending the micro-particles and/or nano-particles in a liquid adapted to swell, soften, and/or deform either the porous materials and/or the particles, thereby forming a liquid-particle suspension. The method further includes adding the suspension to the porous materials; and removing the liquid, thereby forming the porous materials having the micro-particles and/or nano-particles immobilized on the internal pore surfaces and/or the external pore surfaces.Type: ApplicationFiled: August 2, 2012Publication date: November 29, 2012Inventors: Peter X. Ma, Guobao Wei
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Patent number: 8268344Abstract: Porous materials and methods for forming them are disclosed. One method for immobilizing micro-particles and/or nano-particles onto internal pore surfaces and/or external pore surfaces of porous materials includes suspending the micro-particles and/or nano-particles in a liquid adapted to swell, soften, and/or deform either the porous materials and/or the particles, thereby forming a liquid-particle suspension. The method further includes adding the suspension to the porous materials; and removing the liquid, thereby forming the porous materials having the micro-particles and/or nano-particles immobilized on the internal pore surfaces and/or the external pore surfaces.Type: GrantFiled: April 25, 2006Date of Patent: September 18, 2012Assignee: The Regents of The University of MichiganInventors: Peter X. Ma, Guobao Wei
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Publication number: 20110311746Abstract: Various embodiments of scaffolds are disclosed herein. In one embodiment, the scaffold includes a tubular polymeric structure, and a controlled gradient of solid-walled microtubules oriented radially or axially in the tubular polymeric structure. In another embodiment, the scaffold includes a nano-fibrous tubular polymeric structure, and an oriented and interconnected microtubular porous network formed in the nano-fibrous tubular polymeric structure. In still another embodiment, a composite scaffold is formed including a polymeric structure having an inner wall and an outer wall, and at least one electrospun layer positioned along at least one of the inner wall, or the outer wall, or in a middle of the porous polymeric structure.Type: ApplicationFiled: June 2, 2011Publication date: December 22, 2011Applicant: The Regents of the University of MichiganInventors: Peter X. Ma, Haiyun Ma
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Patent number: 7993738Abstract: Modified porous materials are disclosed having interconnected, complexly shaped three-dimensional surfaces. The modification is accomplished by crosslinking the three-dimensional surfaces or by incorporating, in situ, an inorganic material onto or into three-dimensional surfaces. The porous materials are macro structures including at least one of nano-features, micro-features, and combinations thereof. The modifying accomplishes changing surface properties of the porous materials, changing the three-dimensional surfaces, and/or rendering the porous materials substantially stable in a predetermined environment.Type: GrantFiled: January 25, 2008Date of Patent: August 9, 2011Assignee: The Regents of the University of MichiganInventors: Peter X. Ma, Xiaohua Liu
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Publication number: 20100048734Abstract: A water soluble copolymer includes first and second hydrophilic block segments or graft chains. The first hydrophilic block segment or graft chain contains cyclodextrin groups in at least a majority of its repeating units, and the second hydrophilic block segment or graft chain contains repeating units other than cyclodextrin groups. The first and second block segments or graft chains are covalently linked.Type: ApplicationFiled: August 18, 2009Publication date: February 25, 2010Inventors: Peter X. Ma, Jianxiang Zhang
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Publication number: 20080317816Abstract: A porous object includes a porous material having internal pore surfaces and external pore surfaces. Releasing material encapsulated biomolecules are immobilized on at least one of the internal pore surfaces, at least one of the external pore surfaces, or combinations thereof.Type: ApplicationFiled: January 10, 2008Publication date: December 25, 2008Inventors: Peter X. Ma, Guobao Wei, William V. Giannobile, Qiming Jin
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Publication number: 20080268059Abstract: A method for immobilizing micro-particles, nano-particles or combinations thereof onto a surface is disclosed. The method includes distributing the micro-particles, nano-particles or combinations thereof onto the surface. The surface and the particles are exposed to thermal treatment, vapor treatment or combinations thereof, thereby adhering at least some of the micro-particles, nano-particles or combinations thereof to the surface. Materials including such immobilized micro-particles, nano-particles or combinations thereof are also disclosed herein.Type: ApplicationFiled: February 27, 2008Publication date: October 30, 2008Inventors: Peter X. Ma, Guobao Wei
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Publication number: 20080254095Abstract: A delivery device includes a hollow container, and a plurality of biodegradable and/or erodible polymeric layers established in the container. A layer including a predetermined substance is established between each of the plurality of polymeric layers, whereby degradation of the polymeric layer and release of the predetermined substance occur intermittently. Methods for forming the device are also disclosed herein.Type: ApplicationFiled: April 13, 2008Publication date: October 16, 2008Inventors: Peter X. Ma, Xiaohua Liu, Laurie McCauley
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Publication number: 20080213564Abstract: Modified porous materials are disclosed having interconnected, complexly shaped three-dimensional surfaces. The modification is accomplished by crosslinking the three-dimensional surfaces or by incorporating, in situ, an inorganic material onto or into three-dimensional surfaces. The porous materials are macro structures including at least one of nano-features, micro-features, and combinations thereof. The modifying accomplishes changing surface properties of the porous materials, changing the three-dimensional surfaces, and/or rendering the porous materials substantially stable in a predetermined environment.Type: ApplicationFiled: January 25, 2008Publication date: September 4, 2008Inventors: Peter X. Ma, Xiaohua Liu
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Patent number: 7323208Abstract: Modified porous materials are disclosed having interconnected, complexly shaped three-dimensional surfaces. The modification is accomplished by crosslinking the three-dimensional surfaces and/or by coating the three-dimensional surfaces with a layer of a predetermined material. The porous materials are macro structures including at least one of nano-features, micro-features, and combinations thereof. The modifying accomplishes changing surface properties of the porous materials, changing the three-dimensional surfaces, and/or rendering the porous materials substantially stable in a predetermined environment.Type: GrantFiled: November 30, 2004Date of Patent: January 29, 2008Assignee: The Regents of the University of MichiganInventors: Peter X. Ma, Xiaohua Liu
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Publication number: 20070249536Abstract: A three-component polyanhydride copolymer having tunable erosion properties includes a sebacic acid anhydride precursor, a 1,3-bis(carboxyphenoxy) propane anhydride precursor, and a poly(ethylene glycol) anhydride precursor. The erosion rate of the copolymer increases with an increasing amount of the poly(ethylene glycol) precursor. A method for forming the three-component polyanhydride copolymer includes combining the sebacic acid precursor, the 1,3-bis(carboxyphenoxy) propane precursor, and the polyethylene glycol precursor to form a precursor mixture. The precursor mixture is then melt polymerized to form the three-component polyanhydride copolymer.Type: ApplicationFiled: April 25, 2007Publication date: October 25, 2007Inventors: Peter X. Ma, Sijian Hou
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Patent number: 7151120Abstract: A method for preparing a highly porous, high surface area degradable or partially degradable material. The method comprises the steps of mixing a degradable or partially degradable polymer with a mixed solvent comprising a first solvent and a second solvent, wherein the mixed solvent comprises a ratio higher than 1:1, first solvent to second solvent; gelling the mixture; and treating the gel under conditions whereby a substantially solvent free porous structure is created having a porosity greater than about 80%; wherein the material is mechanically strong and has a complex porous structure with nano fibrous architecture.Type: GrantFiled: October 16, 2002Date of Patent: December 19, 2006Assignee: The Regents of the University of MichiganInventor: Peter X. Ma
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Patent number: 6979700Abstract: A method for preparing a highly porous, high surface area non-degradable material includes the steps of mixing a non-degradable polymer with a solvent or mixture of solvents; gelling the mixture; and treating the gel under conditions whereby a substantially solvent free porous structure is created having a porosity greater than about 80%. The resultant material is mechanically strong and has an architecture including at least one of nano fibrous, micro fibrous, non fibrous, complex porous structure with nano fibrous architecture, and mixtures thereof.Type: GrantFiled: October 16, 2002Date of Patent: December 27, 2005Assignee: The Regents of The University of MichiganInventor: Peter X. Ma
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Patent number: 6979702Abstract: An ionomer composite composition having improved and unique physical properties, includes a glass material containing at least one of divalent cations and multivalent cations; and at least one copolymer. The copolymer comprises: at least one hydrophilic monomer containing acid functional groups adapted to react with the at least one of divalent cations and multivalent cations to form ionic crosslinks among polymer chains, the hydrophilic monomer present in an amount sufficient to impart a desired degree of aqueous solubility to the copolymer, and at least one hydrophobic monomer present in an amount sufficient to impart a desired degree of structural stability to the composite composition when exposed to an aqueous environment.Type: GrantFiled: March 16, 2000Date of Patent: December 27, 2005Assignee: The Regents of the University of MichiganInventors: Peter X. Ma, Anne E. Huber
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Patent number: 6899873Abstract: The present invention discloses the design and fabrication of highly porous (up to 97%) scaffolds from biodegradable polymers with a novel phase-separation technique to generate controllable parallel array of micro-tubular architecture. The porosity, diameter of the micro-tubes, the tubular morphology and their orientation may be controlled by the polymer concentration, solvent system and temperature gradient. The mechanical properties of these scaffolds are anisotropic. Osteoblastic cells are seeded in these 3-D scaffolds and cultured in vitro. The cell distribution and the neo-tissue organization are guided by the micro-tubular architecture. The method has general applicability to a variety of polymers, therefore the degradation rate, cell-matrix interactions may be controlled by the chemical composition of the polymers and the incorporation of bioactive moieties. These micro-tubular scaffolds may be used to regenerate a variety of tissues with anisotropic architecture and properties.Type: GrantFiled: January 25, 2002Date of Patent: May 31, 2005Assignee: The Regents of The University of MichiganInventors: Peter X. Ma, Ruiyan Zhang
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Patent number: 6872387Abstract: Methods and compositions are described that provide scaffolds for the support of cells. The scaffolds of the present invention have structural uniformity and desirable mechanical properties that make them suitable for a variety of uses, including uses for in vitro tissue regeneration or in vivo tissue or organ replacement. A method is described for controlling three-dimensional structure of the hydrogel/cell constructs under tissue culture environment.Type: GrantFiled: February 23, 1999Date of Patent: March 29, 2005Assignee: The Regents of the University of MichiganInventor: Peter X. Ma
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Patent number: 6867240Abstract: Methods and compositions are described that provide three dimensional porous matrices as structural templates for cells. The porous matrices of the present invention have desirable mechanical properties suitable to a variety of applications, including platforms for in vitro cell cultivation, implants for tissue and organ engineering, and materials suitable for chromatography and filtration.Type: GrantFiled: August 27, 2001Date of Patent: March 15, 2005Assignee: The Regents of the University of MichiganInventors: Peter X. Ma, Ruiyun Zhang
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Patent number: 6673285Abstract: 3-D biodegradable porous, polymer (natural or synthetic) scaffolds with well-controlled, interconnected pores, and method for forming the porous materials. Hydrophilic and/or hydrophobic porogen materials were fabricated into 3-D negative replicas of the desired macroporous architectures. Biodegradable polymers (PLLA and PLGA) were dissolved in a solvent and cast onto the negative replica. After dissolving/leaching out the porogen materials, a porous polymer scaffold was formed. The skeletal structure of PLLA foams consisted of small platelets or nano-fibers, while PLGA foams had homogeneous skeletal structure. To improve the cell seeding, distribution, mass transport, and new tissue organization and vascularization, 3-D macroporous architectures are built in the nano-fibrous matrices. The method tailors polymer scaffolds for a variety of potential tissue engineering applications due to the well-controlled architecture, inter-pore connectivity, and mechanical properties.Type: GrantFiled: May 11, 2001Date of Patent: January 6, 2004Assignee: The Regents of the University of MichiganInventor: Peter X. Ma