Journal for Biophysical Chemistry

Biointerphases Cover Image
Open Access

Surface plasmon optical study of the interfacial phase transition of elastinlike polypeptide grafted on gold

  • Fei Xu1,
  • Huang Min Joon1,
  • Kimberly Trabbic-Carlson2,
  • Ashutosh Chilkoti2 and
  • Wolfgang Knoll1, 3

Received: 14 May 2008

Accepted: 7 July 2008

Published: 2 October 2008


The conformational changes in elastinlike polypeptides (ELPs) grafted to a solid/solution interface via different architectures were studied using surface plasmon resonance spectroscopy and surface plasmon field-enhanced fluorescence spectroscopy (SPFS). SPFS provides a simple and convenient optical method to study the influence of the grafting method and the graft density on the conformational changes in ELPs at the solid-solution interface as a function of environmental variables. A typical response of the ELP, consistent with its stimuli responsiveness, was a gradual collapse upon increasing the ionic strength; this effect was inversely correlated with the surface graft density of the ELP.