Disclosed herein is a method of controlling the stability of multilayer polypeptide films. A method of controlling the stability of a film, comprises exposing the film to an oxidizing agent or a reducing agent, wherein the film comprises a plurality of layers, the layers comprising alternating oppositely charged polypeptides, wherein a first layer comprises a first layer polypeptide and a second layer comprises a second layer polypeptide, and the first layer polypeptide comprises a sulfhydryl-containing amino acid.