Immobilization of biological cells in polytetrafluoroethylene matrix
AssigneeMinnesota Mining and Manufacturing Company
InventorsLouis A. Errede, George R. Hunt
Life of this patent
Estimating the term…
Abstract
A polytetrafluoroethylene (PTFE) fibril matrix is prepared containing entrapped viable cells such as animal, bacterial, fungal or yeast cells. Cells are blended with surfactant and soap-free PTFE in aqueous dispersion to form a damp paste. Water is added to the paste and a resultant stiff dough is biaxially calendered between calendering rolls to cause fibrillation and form the PTFE fibril matrix. Calendering is preferably carried out at a temperature of 5.degree. to 70.degree. C. and a pressure of 1000 to 3000 MPa. The fibril matrix may be dried.
Claims13
A method of preparing a compsite structure consisting essentially of a polytetrafluoroethylene fibril matrix having entrapped therein 0.005 to 15 parts of viable cells per part of polytetrafluoroethylene by weight, said viable cells being capable of their usual and continuous biochemical and biological performances comprising the steps of:
- (a) providing a blend consisting essentially of viable cells and surfactant-and soap free polytetrafluoroethylene as an aqueous dispersion in the form of a damp paste,
- (b) adding sufficient water as a lubricant to exceed the absorptive capacity of the viable cells yet maintain a stiff dough consistency
- (c) intensively mixing said stiff dough at a temperature in the range of 5.degree. to 70.degree.C. to fibrillate said polytetrafluoroethylene, and
- (d) biaxially calendering the resultant mass between calendering rolls at a temperature in the range of 5.degree. to 70.degree. C. and a pressure in the range of 1000 to 3000 MPa to cause further fibrillation of said polytetrafluorethylene to provide said composite structure, said heating being controlled to preserve the viability of the cells.
A composite structure consisting essentially of a polytetrafluoroethylene fibril matrix having entrapped therein 0.005 to 15 parts of viable cells per part of polytetrafluoroethylene by weight, said viable cells being capable of their usual and continuous biochemical and biological performances, said composite having been prepared by a process comprising the steps of:
- (a) providing a blend consisting essentially of viable cells and surfactant-and soap-free polytetrafluoroethylene as an aqueous dispersion in the form of a damp paste.
- (b) adding sufficient water as a lubricant to exceed the absorptive capacity of the viable cells yet maintain a stiff dough consistency,
- (c) intensively mixing said stiff dough at a temperature in the range of 5.degree. to 70.degree. C. to fibrillate said polytetrafluoroethylene, and
- (d) biaxially calendering the resultant mass between calendering rolls at a temperature in the range of 5.degree. to 70.degree. C. and a pressure in the range of 1000 to 3000 MPa to cause further fibrillation of said polytetrafluoroethylene to provide said composite structure, said heating being controlled to preserve the viability of the cells.
Dependencies are inferred from the claim text.