Highly Hydrophobic Films of Engineered Silk Proteins by a Simple Deposition Method

Teemu Välisalmi (Corresponding Author), Nelmary Roas-Escalona, Kristoffer Meinander, Pezhman Mohammadi, Markus B. Linder (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)

Abstract

Molecular engineering of protein structures offers a uniquely versatile route for novel functionalities in materials. Here, we describe a method to form highly hydrophobic thin films using genetically engineered spider silk proteins. We used structurally engineered protein variants containing ADF3 and AQ12 spider silk sequences. Wetting properties were studied using static and dynamic contact angle measurements. Solution conditions and the surrounding humidity during film preparation were key parameters to obtain high hydrophobicity, as shown by contact angles in excess of 120°. Although the surface layer was highly hydrophobic, its structure was disrupted by the added water droplets. Crystal-like structures were found at the spots where water droplets had been placed. To understand the mechanism of film formation, different variants of the proteins, the topography of the films, and secondary structures of the protein components were studied. The high contact angle in the films demonstrates that the conformations that silk proteins take in the protein layer very efficiently expose their hydrophobic segments. This work reveals a highly amphiphilic nature of silk proteins and contributes to an understanding of their assembly mechanisms. It will also help in designing diverse technical uses for recombinant silk.
Original languageEnglish
Pages (from-to)4370-4381
Number of pages12
JournalLangmuir
Volume39
Issue number12
DOIs
Publication statusPublished - 28 Mar 2023
MoE publication typeA1 Journal article-refereed

Keywords

  • Animals
  • Silk/chemistry
  • Water/chemistry
  • Hydrophobic and Hydrophilic Interactions
  • Wettability
  • Spiders
  • Recombinant Proteins/chemistry

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