Protein-engineering techniques are powerful alternatives to traditional chemical polymerization methods to synthesize monodisperse polymers, as they offer exquisite control over molecular weight, sequence, architecture and functionality. Due to their intrinsic biocompatibility, these systems are highly attractive alternatives to traditional synthetic polymers for biomedical applications, especially drug-delivery where most recombinant polymers are based on the pentapeptide repeat [-Val-Pro-Gly-Val-Gly-] derived from the elastomeric domain of elastin. An essential property of elastin-based sequences is their temperature-triggered phase transition (LCST or Tt). This behavior has been exploited to create temperature-triggered self-assembly of portein block copolymers. Raising the solution temperature can selectively desolvate one block and drive the self-assembly above a critical micellization temperature (CMT) into micellar structures. Self-assembly can be controlled with hydrophilic-to-hydrophobic block ratio, copolymer MW, and distribution of polar and apolar regions along the polymer chain. We have recently designed a series of recombinant amphiphilic diblock copolymers wherein the hydrophobic block (30<Tt1<45�C) contains multiple repeats of hydrophobic (VPGVG) motifs and the hydrophilic block with a higher transition temperature (Tt2>60�C) contains repeats of 30 or 60 (VPGXG) motifs with where X is alanine or glycine at a 1:1 ratio. The hydrophilic mass fraction of the copolymer was tuned from 10 to 60%. Extensive analysis (DLS, SANS, TEM, AFM) of the self-assembly behavior of these diblock peptide polymers were performed and relationships between their chemical composition, sequence, and nanoscale structure will be discussed. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/239nm/uploads/7615_untitled.jpg' alt='' />

Elastin-based amphiphilic copolymers as precision building blocks for controlled self-assembly

246th National Meeting (2013)

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