Patents by Inventor Hai-Quan Mao

Hai-Quan Mao 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).

  • Publication number: 20080176959
    Abstract: The present invention is directed to a biodegradable system for the controlled release of bioactive substances. This system comprises novel biodegradable and biocompatible polyphosphoesters that carry positive charges. Process for making these polyphosphoesters, compositions containing these polyphosphoesters and biologically active substances, articles and methods for delivery of drugs and genes using this system are described. A controlled gene delivery system based on these polyphosphoesters is prepared by complex coacervation of nucleic acid (DNA or RNA) with polymers. The release rates can be manipulated by adjusting the charge ratios of polyphosphoesters to nucleic acids. This gene delivery system yields a higher gene expression in muscle when injected intramuscularly.
    Type: Application
    Filed: January 17, 2008
    Publication date: July 24, 2008
    Inventors: Jun WANG, Hai-Quan MAO, Kam Weng LEONG
  • Publication number: 20080153163
    Abstract: The instant invention provides methods and compositions for the expansion and differentiation of stem cells.
    Type: Application
    Filed: October 18, 2007
    Publication date: June 26, 2008
    Applicant: The Johns Hopkins University
    Inventors: Hai-Quan Mao, Leong Kam, Kian-Ngiap Chua, Sreeram Ramakrishna
  • Patent number: 7345138
    Abstract: The present invention is directed to a biodegradable system for the controlled release of bioactive substances. This system comprises novel biodegradable and biocompatible polyphosphoesters that carry positive charges. Process for making these polyphosphoesters, compositions containing these polyphosphoesters and biologically active substances, articles and methods for delivery of drugs and genes using this system are described. A controlled gene delivery system based on these polyphosphoesters is prepared by complex coacervation of nucleic acid (DNA or RNA) with polymers. The release rates can be manipulated by adjusting the charge ratios of polyphosphoesters to nucleic acids. This gene delivery system yields a higher gene expression in muscle when injected intramuscularly.
    Type: Grant
    Filed: May 14, 2002
    Date of Patent: March 18, 2008
    Assignee: Johns Hopkins Singapore PTE Ltd.
    Inventors: Jun Wang, Hai-Quan Mao, Kam Weng Leong
  • Publication number: 20050169969
    Abstract: A medical device and method for transportation and release of a therapeutic agent into a mammalian body are disclosed. The medical device is coated with alternating layers of a negatively charged therapeutic agent and a cationic polyelectrolyte, following a controlled adsorption technique. The method is simple, with minimal perturbation to the therapeutic agent and uses clinically acceptable biopolymers such as human serum albumin. The amount of the therapeutic agent that can be delivered by this technique is optimized by the number of the layers of the therapeutic agent adsorbed on the surface of medical device. There is a washing step between alternate layers of the therapeutic agent and cationic polyelectrolyte carrier, so that the amount of the therapeutic agent on the insertable medical device represents the portion that is stably entrapped and adsorbed on to the medical device.
    Type: Application
    Filed: February 17, 2005
    Publication date: August 4, 2005
    Inventors: Weiping Li, Hai-Quan Mao, Kam Leong
  • Publication number: 20050131200
    Abstract: The present invention is directed to a biodegradable system for the controlled release of bioactive substances. This system comprises novel biodegradable and biocompatible polyphosphoesters that carry positive charges. Process for making these polyphosphoesters, compositions containing these polyphosphoesters and biologically active substances, articles and methods for delivery of drugs and genes using this system are described. A controlled gene delivery system based on these polyphosphoesters is prepared by complex coacervation of nucleic acid (DNA or RNA) with polymers. The release rates can be manipulated by adjusting the charge ratios of polyphosphoesters to nucleic acids. This gene delivery system yields a higher gene expression in muscle when injected intramuscularly.
    Type: Application
    Filed: May 14, 2002
    Publication date: June 16, 2005
    Inventors: Jun Wang, Hai-Quan Mao, Kam Leong
  • Publication number: 20050119450
    Abstract: The present invention is directed to a series of new polycationic biodegradable polyphosphoramidates. Process for making the polymers, compositions containing these polymers and bioactive ligands to enhance the cellular uptake ad intracellular trafficking, articles and methods for delivery of drugs and genes using these polymers are described. A gene delivery system based on these polymers is prepared by complex coacervation of nucleic acid (DNA or RNA) with polymers. Targeting ligands and molecules that could facilitate gene transfer can be conjugated to polymers to achieve selective and enhanced gene delivery. The current invention also provides a complex composition with buffering capacity.
    Type: Application
    Filed: May 14, 2002
    Publication date: June 2, 2005
    Inventors: Jun Wang, Hai-Quan Mao, Kam Leong
  • Patent number: 6899731
    Abstract: A medical device and method for transportation and release of a therapeutic agent into a mammalian body are disclosed. The medical device is coated with alternating layers of a negatively charged therapeutic agent and a cationic polyelectrolyte, following a controlled adsorption technique. The method is simple, with minimal perturbation to the therapeutic agent and uses clinically acceptable biopolymers such as human serum albumin. The amount of the therapeutic agent that can be delivered by this technique is optimized by the number of the layers of the therapeutic agent adsorbed on the surface of medical device. There is a washing step between alternate layers of the therapeutic agent and cationic polyelectrolyte carrier, so that the amount of the therapeutic agent on the insertable medical device represents the portion that is stably entrapped and adsorbed on to the medical device.
    Type: Grant
    Filed: January 2, 2001
    Date of Patent: May 31, 2005
    Assignee: Boston Scientific Scimed, Inc.
    Inventors: Weiping Li, Hai-Quan Mao, Kam W. Leong
  • Publication number: 20050058685
    Abstract: The present invention describes a method to immobilize high density of cell-specific ligands on polymeric surface for cell engineering applications. This method combines a surface-grafting polymerization procedure to yield high density of functional groups, and a chemical conjugation step to link cell-specific ligands to the surface functional groups. This surface functionalization scheme can be applied to polymeric materials in various forms, such as polymer membrane, film, fiber, hollow fiber, foam, etc. Tissue-engineering scaffolds can be functionalized with cell specific ligand in the same manner.
    Type: Application
    Filed: September 6, 2003
    Publication date: March 17, 2005
    Inventors: Hai-Quan Mao, Chao Yin, Ron-Xi Zhuo, Kam Leong
  • Patent number: 6852709
    Abstract: The present invention provides biodegradable polymers, polymer compositions, particles composed thereof and methods of using same for the controlled release of a biologically active substance to a specified tissue or cells. Preferred polymers include biodegradable, amphiphilic polyphosphates which are capable of complexing one or more biologically active substances. Preferred methods include the controlled release of biologically active substances and gene therapy using polymers and nanoparticles composed thereof.
    Type: Grant
    Filed: May 31, 2001
    Date of Patent: February 8, 2005
    Assignee: Johns Hopkins University
    Inventors: Kam Leong, Wen Jie, Hai-Quan Mao
  • Patent number: 6805876
    Abstract: Featured are biodegradable polymers comprising repeat units derived from cyclic phosphate monomers and optionally further comprising repeat units derived from lactide or caprolactone monomers. Also featured are methods for preparing the biodegradable polymers of the invention and biodegradable polymer compositions comprising a biologically active substance and a biodegradable polymer. Additionally featured are articles and microspheres prepared from biodegradable polymers and polymer compositions of the invention. Further, methods for the controlled release of a biologically active substance using the biodegradable polymers of the invention are also described.
    Type: Grant
    Filed: March 10, 2001
    Date of Patent: October 19, 2004
    Assignee: Johns Hopkins University
    Inventors: Kam W. Leong, Wen Jie, Ren-Xi Zhuo, Hai-Quan Mao
  • Patent number: 6800672
    Abstract: Biodegradable, flowable or flexible polymer compositions are described comprising a polymer having the recurring monomeric units shown in formula I: wherein: each of R and R′ is independently straight or branched alkylene, either unsubstituted or substituted with one or more non-interfering substituents; L is a divalent cycloaliphatic group; R″ is selected from the group consisting of H, alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; and n is 5 to 1,000, wherein said biodegradable polymer is biocompatible before and upon biodegradation. In one embodiment, one or more of R, R′ or R″ is a biologically active substance. Amorphous compositions containing a biologically active substance, in addition to the polymer, and methods for controllably releasing biologically active substances using the compositions, are also described.
    Type: Grant
    Filed: December 4, 2001
    Date of Patent: October 5, 2004
    Assignees: Guilford Pharmaceuticals, Inc., Johns Hopkins University School of Medicine
    Inventors: Wenbin Dang, Irina Kadiyala, Zhong Zhao, James P. English, Hai-quan Mao, Kam W. Leong
  • Patent number: 6600010
    Abstract: Biodegradable terephthalate polymers are described comprising the recurring monomeric units shown in formula I: wherein R is a divalent organic moiety; R′ is an aliphatic, aromatic or heterocyclic residue; x is ≧1; and n is 0-5,000, wherein the biodegradable polymer is biocompatible before and upon biodegradation. Processes for preparing the polymers, compositions containing the polymers and biologically active substances, articles useful for implantation or injection into the body fabricated from the compositions, and methods for controllably releasing biologically active substances using the polymers, are also described.
    Type: Grant
    Filed: August 2, 2001
    Date of Patent: July 29, 2003
    Assignees: Guilford Pharmaceuticals, Inc., John Hopkins University
    Inventors: Hai-Quan Mao, Kam W. Leong, Wenbin Dang, Hungnan Lo, Zhong Zhao, David P. Nowotnik, James P. English
  • Patent number: 6548302
    Abstract: The present invention relates to compositions and methods for delivery of nucleic acids. In particular, the invention provides a polymeric delivery formulation including a nucleic acid to be transfected into a host cell, formulated in a biodegradable polymer having phosphorous-based linkages.
    Type: Grant
    Filed: June 18, 1999
    Date of Patent: April 15, 2003
    Assignee: Johns Hopkins University School of Medicine
    Inventors: Hai-Quan Mao, Kevin Y. Lin, Bart S. Hendriks, Kam W. Leong, Michael F. Haller
  • Patent number: 6485737
    Abstract: A medical device is described comprising a biodegradable terephthalate copolymer comprising the recurring monomeric units shown in formula I: wherein R is a divalent organic moiety; R′ is an aliphatic, aromatic or heterocyclic residue; x is ≧1; and n is 3-7, 500, where the biodegradable polymer is sufficiently pure to be biocompatible and is capable of forming biocompatible residues upon biodegradation. Compositions containing the copolymers and biologically active substances, articles useful for implantation or injection into the body fabricated from the compositions, and methods for controllably releasing biologically active substances using the copolymers, are also described.
    Type: Grant
    Filed: November 27, 2000
    Date of Patent: November 26, 2002
    Assignee: Guilford Pharmaceuticals, Inc.
    Inventors: Hai-quan Mao, Kam W. Leong, Zhong Zhao, Wenbin Dang, James P. English, David P. Nowotnik
  • Publication number: 20020155092
    Abstract: Featured are biodegradable polymers comprising repeat units derived from cyclic phosphate monomers and optionally further comprising repeat units derived from lactide or caprolactone monomers. Also featured are methods for preparing the biodegradable polymers of the invention and biodegradable polymer compositions comprising a biologically active substance and a biodegradable polymer. Additionally featured are articles and microspheres prepared from biodegradable polymers and polymer compositions of the invention. Further, methods for the controlled release of a biologically active substance using the biodegradable polymers of the invention are also described.
    Type: Application
    Filed: March 10, 2001
    Publication date: October 24, 2002
    Inventors: Kam Leong, Wen Jie, Ren-Xi Zhuo, Hai-Quan Mao
  • Publication number: 20020151617
    Abstract: Biodegradable polymers are described comprising the recurring monomeric units shown in formula I or II: 1
    Type: Application
    Filed: January 15, 2002
    Publication date: October 17, 2002
    Inventors: Hai-Quan Mao, Kam W. Leong, Zhong Zhao, James P. English
  • Publication number: 20020137814
    Abstract: Biodegradable, flowable or flexible polymer compositions are described comprising a polymer having the recurring monomeric units shown in formula I: 1
    Type: Application
    Filed: December 4, 2001
    Publication date: September 26, 2002
    Inventors: Wenbin Dang, Irina Kadiyala, Zhong Zhao, James P. English, Hai-Quan Mao, Kam W. Leong
  • Patent number: 6419709
    Abstract: An essentially non-osteoconductive medical device is described comprising a biodegradable terephthalate copolymer comprising the recurring monomeric units shown in formula I: wherein R is a divalent organic moiety; x is ≧1; and n is 3-7,500, where the biodegradable polymer is sufficiently pure to be biocompatible and is capable of forming biocompatible residues upon biodegradation. Compositions containing the copolymers and biologically active substances, articles useful for implantation or injection into the body fabricated from the compositions, and methods for controllably releasing biologically active substances using the copolymers, are also described.
    Type: Grant
    Filed: October 2, 1998
    Date of Patent: July 16, 2002
    Assignees: Guilford Pharmaceuticals, Inc., John Hopkins University School of Medicine
    Inventors: Hai-quan Mao, Kam W. Leong, Zhong Zhao, Wensin Dang, James P. English, David P. Nowotnik
  • Publication number: 20020091230
    Abstract: Biodegradable terephthalate polymers are described comprising the recurring monomeric units shown in formula I: 1
    Type: Application
    Filed: August 2, 2001
    Publication date: July 11, 2002
    Inventors: Hai-Quan Mao, Kam W. Leong, Wenbin Dang, Hungnan Lo, Zhong Zhao, David P. Nowotnik, James P. English
  • Patent number: 6403675
    Abstract: Biodegradable, flowable or flexible polymer compositions are described comprising a polymer having the recurring monomeric units shown in formula I: wherein: each of R and R′ is independently straight or branched alkylene, either unsubstituted or substituted with one or more non-interfering substituents; L is a divalent cycloaliphatic group; R″ is selected from the group consisting of H, alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; and n is 5 to 1,000, wherein said biodegradable polymer is biocompatible before and upon biodegradation. In one embodiment, one or more of R, R′ or R″ is a biologically active substance. Amorphous compositions containing a biologically active substance, in addition to the polymer, and methods for controllably releasing biologically active substances using the compositions, are also described.
    Type: Grant
    Filed: April 30, 1998
    Date of Patent: June 11, 2002
    Assignees: Guilford Pharmaceuticals, Inc., Johns Hopkins University
    Inventors: Wenbin Dang, Hai-quan Mao, Irina Kadiyala, Kam W. Leong, Zhong Zhao, James P. English