Overview
PhaseBio's proprietary technology is based on recombinant elastin-like peptides (ELPs), which are thermally responsive biopolymers composed of a Val-Pro-Gly-Xaa-Gly pentapeptide repeat. These sequences are derived from a structural motif found in mammalian elastin. The guest residue Xaa can be any amino acid except proline. ELPs undergo an inverse temperature phase transition in response to an increase in temperature. ELPs are soluble in an aqueous solution at temperatures below their transition temperature (Tt) but become insoluble and aggregate at temperatures above their Tt. (Figure 1). The inverse temperature phase transition is fully reversible, such that an aggregated ELP becomes soluble when the temperature is decreased below its Tt. The Tt can be “tuned”, dialed-up or dialed-down by changing any one of the following variables: the ELP’s guest residue, the ELP’s concentration of molecular weight or the salt concentration of the solution.
Figure 1. ELPs Transition from Liquid to Solid
For more information on inverse temperature phase transition, see our video.