What is claimed is:
1. A tissue sealant for sealing a biological tissue of a living mammal, the sealant comprising a hydrogel, the hydrogel being formed by gelation of a premix, the premix comprising an alkylated chitosan or a gelatin, and a polybasic carboxylic acid or an oxidized polysaccharide, in an aqueous medium.
CLAIM OF PRIORITY FROM A PRIOR-FILED APPLICATION
This application is a continuation-in-part of U.S. patent application Ser. No. 11/379,182, filed Apr. 18, 2006, which is incorporated herein by reference, and claims the priority thereof.