Functional Modification of Silica through Enhanced Adsorption of Elastin-Like Polypeptide Block Copolymers

Biomacromolecules. 2018 Feb 12;19(2):298-306. doi: 10.1021/acs.biomac.7b01307. Epub 2017 Dec 12.

Abstract

A powerful tool for controlling interfacial properties and molecular architecture relies on the tailored adsorption of stimuli-responsive block copolymers onto surfaces. Here, we use computational and experimental approaches to investigate the adsorption behavior of thermally responsive polypeptide block copolymers (elastin-like polypeptides, ELPs) onto silica surfaces, and to explore the effects of surface affinity and micellization on the adsorption kinetics and the resultant polypeptide layers. We demonstrate that genetic incorporation of a silica-binding peptide (silaffin R5) results in enhanced adsorption of these block copolymers onto silica surfaces as measured by quartz crystal microbalance and ellipsometry. We find that the silaffin peptide can also direct micelle adsorption, leading to close-packed micellar arrangements that are distinct from the sparse, patchy arrangements observed for ELP micelles lacking a silaffin tag, as evidenced by atomic force microscopy measurements. These experimental findings are consistent with results of dissipative particle dynamics simulations. Wettability measurements suggest that surface immobilization hampers the temperature-dependent conformational change of ELP micelles, while adsorbed ELP unimers (i.e., unmicellized block copolymers) retain their thermally responsive property at interfaces. These observations provide guidance on the use of ELP block copolymers as building blocks for fabricating smart surfaces and interfaces with programmable architecture and functionality.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adsorption
  • Elastin / chemistry*
  • Micelles*
  • Molecular Dynamics Simulation
  • Peptide Fragments / chemistry*
  • Protein Precursors / chemistry*
  • Silicon Dioxide / chemistry*
  • Wettability

Substances

  • Micelles
  • Peptide Fragments
  • Protein Precursors
  • R5 peptide, silaffin-1 precursor
  • Silicon Dioxide
  • Elastin