Artificial protein block polymer libraries bearing two SADs: Effects of elastin domain repeats

We have generated protein block polymer EnC and CE _n libraries composed of two different self-assembling domains (SADs) derived from elastin (E) and the cartilage oligomeric matrix protein coiled-coil (C). As the E domain is shortened, the polymers exhibit an increase in inverse transition temperature (Tt); however, the range of temperature change differs dramatically between the EnC and CE _n library. Whereas all polymers assemble into nanoparticles, the bulk mechanical properties of the EnC are very different from CEn. The EnC members demonstrate viscolelastic behavior under ambient conditions and assemble into elastic soft gels above their Tt values. By contrast, the CE _n members are predominantly viscous at all temperatures. All library members demonstrate binding to curcumin. The differential thermoresponsive behaviors of the EnC and CE _n libraries in addition to their small molecule recognition abilities make them suitable for potential use in tissue engineering and drug delivery.