Patents by Inventor Subramanian Gunasekaran

Subramanian Gunasekaran 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: 20030203008
    Abstract: The present invention relates to methods for preparing collagen, especially type I collagen. In particular, the present invention provides methods for the preparation of collagen suitable for biomedical and veterinary applications. The collagen prepared according to the present invention provides numerous desirable characteristics for applications such as implantation, transplantation, and grafting.
    Type: Application
    Filed: April 2, 2003
    Publication date: October 30, 2003
    Inventor: Subramanian Gunasekaran
  • Patent number: 6548077
    Abstract: Purified collagen such a type I collagen is produced by a method containing steps of contacting collagen with a first proteolytic enzyme followed by contacting with a reducing agent and a second proteolytic enzyme. Preferably, the first and second proteolytic enzymes are papain and the reducing agent is sodium sulfide, dithiothreitol, glutathionine or sodium borohydride. In a further step, the purified collagen may be contacted with a delipidation agent such as a mixture of chloroform and methanol to produce delipidated collagen. The delipidated collagen may be filter-sterilized and contacted with a phosphorylation agent such as sodium trimetaphosphate to produce phosphorylated collagen. The delipidated collagen may also be treated by compressing, dehydrating, dispersing and drying to form collagen fibers. De-epithelializing of the collagen may carried out prior to treating with the first proteolytic enzyme. The collagen may be solubilized using a solubilizing agent such as acetic acid.
    Type: Grant
    Filed: October 3, 2000
    Date of Patent: April 15, 2003
    Inventor: Subramanian Gunasekaran
  • Patent number: 6127143
    Abstract: Purified collagen is produced by a method containing steps of contacting a collagen sample with a first proteolytic enzyme followed by contacting with a reducing agent and a second proteolytic enzyme. Preferably, the first and second proteolytic enzymes are papain and the reducing agent is sodium sulfide, dithiothreitol, glutathionine or sodium borohydride. A biocompatible collagen is prepared by contacting the purified collagen with a delipidation agent such as chloroform or methanol to produce delipidated collagen, and then contacting the delipidated collagen with a phosphorylation agent such as sodium trimetaphosphate. Prior to phosphorylation, the delipidated collagen may be treated by compressing, dehydrating, dispersing and drying to form collagen fibers. Also, prior to phosphorylation, the delipidated collagen may be treated by filter-sterilizing. De-epithelializing of the collagen may carried out prior to treating with the first proteolytic enzyme.
    Type: Grant
    Filed: September 28, 1998
    Date of Patent: October 3, 2000
    Inventor: Subramanian Gunasekaran
  • Patent number: 5814328
    Abstract: Purified collagen is produced by contacting a collagen sample with a first proteolytic enzyme, a reducing agent and a second proteolytic enzyme. Preferably, the first and second proteolytic enzymes are papain and the reducing agent is sodium sulfide, dithiothreitol, glutathionine or sodium borohydride. The purified collagen may be contacted with a delipidation agent such as chloroform or methanol and with a phosphorylation agent such as sodium trimetaphosphate to form a biocompatible collagen. Prior to phosphorylation, the delipidated collagen may be treated by compressing, dehydrating, dispersing and drying to form collagen fibers. Also, prior to phosphorylation, the delipidated collagen may be subjected to filter-sterilizing. De-epithelializing of the collagen may carried out prior to treating with the first proteolytic enzyme.
    Type: Grant
    Filed: January 13, 1997
    Date of Patent: September 29, 1998
    Inventor: Subramanian Gunasekaran
  • Patent number: 5455231
    Abstract: Mineralized collagen is prepared by forming calcium phosphate mineral under mild agitation in situ in the presence of dispersed collagen fibrils. A stable composition is obtained with desirable physical characteristics mimicking the characteristics of bone.
    Type: Grant
    Filed: November 23, 1992
    Date of Patent: October 3, 1995
    Assignee: Norian Corporation
    Inventors: Brent R. Constantz, Subramanian Gunasekaran
  • Patent number: 5231169
    Abstract: Mineralized collagen is prepared by forming calcium phosphate mineral under mild agitation in situ in the presence of dispersed collagen fibrils. A stable composition is obtained with desirable physical characteristics mimicking the characteristics of bone.
    Type: Grant
    Filed: February 26, 1992
    Date of Patent: July 27, 1993
    Assignee: Norian Corporation
    Inventors: Brent R. Constantz, Subramanian Gunasekaran