Silk cocoons are used to directly prepare biodegradable silk articles by a thermoplastic method. Combining the silk cocoons with plasticizers, inorganic salts, and biopolymers can add bulk, reduce costs, maintain degradability and provide tunability of the material properties of the silk articles. The on-demand degradation of these silk articles is achieved by exposure to moisture, enzyme solutions or activation of embedded proteases within the article.

Compositions and methods useful for the inhibition of cancer metastasis are disclosed.