Patent ID: 7348399

Claim:
A thin film comprising a plurality of layers of polypeptides, wherein adjacent layers are oppositely charged, wherein a first layer comprises a first layer polypeptide and a second layer comprises a second layer polypeptide, wherein the first layer polypeptide is not a homopolymer, is at least 15 amino acid residues long, has a balance of charge at pH 7 greater than or equal to approximately one-half of its total length and comprises one or more first amino acid sequence motifs, wherein each of the one or more first amino acid sequence motifs has a length of 5 to 15 amino acid residues, and a balance of charge at pH 7 greater than or equal to approximately one-half of its length, wherein the second layer polypeptide is at least 15 amino acid residues long, has a balance of charge at pH 7 greater than or equal to approximately one-half of its total length and of opposite polarity to that of the first layer polypeptide, and comprises one or more second amino acid sequence motifs, wherein each of the second amino acid sequence motifs has a length of 5 to 15 amino acid residues, and a balance of charge at pH 7 greater than or equal to approximately one-half of its length, and with the proviso that: 1) each of the first amino acid sequence motifs consists of 9 amino acid residues and has a balance of charge at pH 7 of 5/9; 2) each of the first amino acid sequence motifs consists of 7 amino acid residues and has a balance of charge at pH 7 of 4/7; 3) the first layer polypeptide comprises at least two first amino acid sequence motifs that are the same or different and are covalently joined by a glycine or proline linker; or 4) the second layer polypeptide comprises at least two second amino acid sequence motifs that are the same or different and are covalently joined by a glycine or proline linker.