Elastin Like Polypeptides (ELPs) are synthetic biopolymers that mimic the properties of natural elastin. They are composed of repeating units of a pentapeptide sequence, typically Val-Pro-Gly-Xaa-Gly, where Xaa can be any amino acid except proline. These sequences give ELPs their unique property of reversible phase transition, which is a significant focus in nanotechnology research.