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Crosslinkable polypeptide compositions
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Inventors: Sojomihardjo, Soebianto A.; Desai, Neil P.; Sandford, Paul A.; Soon-Shiong, Patrick; Nagrani, Shubhi;
Assignee: American Bioscience, Inc. (Santa Monica, CA)
Primary Examiner: Russel; Jeffrey E.
Assistant Examiner:
Attorney, Agent or Firm: Reiter; Stephen E. Foley & Reiter
In accordance with the present invention, there are provided rapidly crosslinkable polypeptides which are obtained upon introduction of unsaturated group(s) into the polypeptide via linkage to amino acid residues on the polypeptide directly through one of three types of linkages, namely, an amide linkage, an ester linkage, or a thioester linkage. Each of these linkages are obtainable in a single step by use of a single derivatizing agent, acrylic anhydride. Also provided are methods for preparing such modified polypeptides and various uses therefor. It has unexpectedly been found that proteins with the above-described chemical modifications have the ability to rapidly crosslink to themselves under suitable conditions. This crosslinking occurs in the absence of any external crosslinking agents (indeed, in the absence of any extraneous agents), resulting in the formation of a solid gel material. Solid crosslinked gels are formed in seconds, starting from a freely flowing solution of polypeptide. Applications of such materials are broad ranging, including the encapsulation of living cells, the encapsulation of biologically active materials, the in situ formation of degradable gels, the formation of wound dressings, the prevention of post-surgical adhesions, gene delivery, drug targetting, as a microcarrier for culture of living cells, and the like. |
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DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, there are provided chemically modified polypeptides having the formula: P--(A--C(O)--Y).
sub.
n wherein: P is any polypeptide, A is a linking moiety which, in combination with a carbonyl moiety, links Y to P, Y is an unsaturated group capable of undergoing free radical polymerization, and n is at least 1.
Virtually any polypeptide can be used in the practice of the present invention, including naturally occurring polypeptides, synthetic polypeptides, short chain peptides having only a few residues, extremely high molecular weight polypeptides, and the like.
The linking moiety "A" employed in the practice of the present invention to link unsaturated group, Y (via a carbonyl) to polypeptide P is typically derived from a reactive residue on the polypeptide backbone.
Thus, A is generally selected from --O--, --S--, --NR-- or alkylene, or an --O--, --S-- or --NR--containing alkylene moiety, wherein R is selected from hydrogen or lower alkyl.
Y of the above formula can be any alkene-containing moiety or alkyne-containing moiety, with terminal unsaturation preferred because such species are more reactive than internally unsubstituted compounds.
Thus, a preferred group of species which are contemplated for use in the practice of the present invention are defined as follows: --C(R).
dbd.
CR'.
sub.
2, or --C.
ident.
CR' wherein: R is selected from hydrogen, lower alkyl or substituted lower alkyl, and R' is selected from hydrogen or lower alkyl.
It is preferred that each R' in the above formulae is hydrogen, with Y being --CH.
dbd.
CH.
sub.
2 or --C.
ident.
CH preferred.
The degree of substitution on polypeptide, P, can vary widely.
Typically, n of the above general formula falls in the range of 1 up to about 500, with n in the range of about 2-300 preferred; and n in the range of about 3-100 especially preferred.
For many medium sized proteins, n can fall in as narrow a range as 5 up to about 60.
Of course, those of skill in the art recognize that the desired level of substitution will vary depending on the ultimate use contemplated
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Gene Therapy 
