This invention provides a kit for making an adhesive and/or a sealant which includes: a first composition of alginate and a multivalent cation salt at a concentration ratio (mg/ml) of 30:1 to 1:60, and a second composition of alginate and a buffer, wherein the buffer has a p H value of between 2 to 7. The invention also provides a method for making a sealant or an adhesive, by contacting the first composition and the second composition.