The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 04, 1983
Filed:
Apr. 28, 1982
Franklin Lim, Richmond, VA (US);
Damon Corporation, Needham Heights, MA (US);
Abstract
Disclosed is a process for microencapsulating a core material and subsequently releasing the core material by selectively disrupting the membranes of the microcapsules. The encapsulation technique involves the formation of a semipermeable membrane, e.g., around a droplet, through the formation of multiple ionic salt bonds between a polyionic polymer in the droplet and a crosslinking polyionic polymer which possesses multiple ionic groups of opposite charge. The membrane can be selectively disrupted by exposing it first to a solution of competing crosslinking multivalent (preferably di or trivalent) ions followed by a solution of a competing polyionic polymer of the same charge as the polymer in the original droplet. Alternatively, a mixed solution of the two competing solutions may be used together. For example, a membrane comprising anionic alginate salt bonded to cationic polymer can be selectively disrupted by exposing the membrane to a mixed solution of monatomic, multivalent cations, e.g. Ca++ ions, and a water-soluble polymer have plural anionic moieties, e.g., heparin, and subsequently sequestering the monatomic cations. The process may be used to encapsulate and subsequently release cell cultures without damage to the cells.