AVS 46th International Symposium
    Biomaterial Interfaces Group Friday Sessions
       Session BI-FrM

Paper BI-FrM3
Reversible Immobilization of a Thermally-Responsive Fusion Protein on a Hydrophobic Surface

Friday, October 29, 1999, 9:00 am, Room 613/614

Session: Interface, Properties, and Modification
Presenter: W. Frey, Duke University
Authors: W. Frey, Duke University
N.A. Hattangadi, Duke University
D.E. Meyer, Duke University
A. Chilkoti, Duke University
Correspondent: Click to Email
Elastin-like polypeptides (ELPs), which are composed of repeats of the Val-Pro-Gly-X-Gly (X is a variable residue) pentapeptide, undergo a phase transition as a function of temperature. ELPs are soluble in water below their transition temperature, and are insoluble in water and aggregate when the temperature is raised above the transition temperature. We have synthesized a thioredoxin-ELP fusion protein (Trx-ELP), and shown by ellipsometry, surface plasmon resonance spectroscopy, and atomic force microscopy that below its transition temperature, soluble Trx-ELP does not interact with a hydrophobic surface. However, above the transition temperature, insoluble Trx-ELP forms an adsorbed monolayer on a hydrophobic surface, in which Trx is oriented towards the bulk. Adsorbed Trx-ELP binds an anti-thioredoxin monoclonal antibody with high affinity from solution. The Trx-ELP/antibody complex can be resolubilized from the surface by reducing the solution temperature below the transition temperature. The adsorption transition is driven exclusively by the hydrophobic surface, because no adsorption is observed on a hydrophilic surface, and previously aggregated Trx-ELP in solution does not adsorb onto a hydrophobic surface. The adsorbed Trx-ELP complex shows micelle-like organization, with a mean diameter of approximately 100 nm. Current studies on reversible self-organization of ELP fusion proteins onto micro and nano-patterned surfaces, based on an easily controllable solution parameter, suggest their application in biosensor development and modulation of cell-substrate interactions.