PROBLEM TO BE SOLVED: To effectively and profitably obtain a biopolymer/polyallylamine complex which comprises a biopolymer such as silk protein and a neutralized or non-neutralized polyallylamine, is useful in the fields of biochemistry and medicine, and has excellent cell adhesivity, excellent cell-proliferating property, excellent physical properties such as excellent strength, and good formability.
SOLUTION: This biopolymer/polyallylamine complex comprises (A) a biopolymer such as silk protein, wool keratin, collagen, gossamer or marine protein and (B) a neutralized or non-neutralized polyallylamine having a positive electric charge in the molecule. It is preferable that the complex has a cell adhesion.proliferation-reinforcing function. The complex is preferably treated with an aqueous water-insolubilizing agent solution to introduce cross-linking bonds between the biopolymer and the polyallylamine. The aqueous water- insolubilizing agent solution is obtained by adding an epoxy compound, an aldehyde or both the compounds to a water-alcohol mixture solution. The components A and B are preferably mixed in an aqueous solution or aqueous dispersion state and then evaporated and dried.