A composite tissue formed in situ is provided. The composite tissue includes a synovial joint tissue; and a barrier material adhered thereto for sealing the synovial joint tissue against synovial fluid. Also provided is a method for regenerating synovial joint tissue in situ by excluding synovial fluid therefrom. The method includes providing a synovial joint tissue having a defect; and placing a barrier material in intimate contact with the defect for sealing the defect against synovial fluid. The barrier material includes a curable protein copolymer. The method further includes curing the protein copolymer in situ. The barrier material can include a crosslinked network, or a self gelled network of repeating elastin-like and fibroin-like polymer chains.