Exploiting Covalent, H-Bonding, and π-πInteractions to Design Antibacterial PDMS Interfaces That Load and Release Salicylic Acid

Ioritz Sorzabal-Bellido, Yuri A. Diaz-Fernandez*, Arturo Susarrey-Arce, Adam A. Skelton, Fiona McBride, Alison J. Beckett, Ian A. Prior, Rasmita Raval

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

12 Citations (Scopus)


Smart antimicrobial surfaces are a powerful tool to prevent bacterial colonization at surfaces. In this work, we report a successful strategy for the functionalization of polydimethylsiloxane (PDMS) surfaces, widely used in medical devices, with salicylic acid (SA), a biocide approved for use in humans. Antimicrobial PDMS surfaces were fabricated via a rational design in which bifunctional silane linker molecules were covalently grafted onto the PDMS via one end, while soft intermolecular interactions with SA were generated at the other end to enable reversible load and release of the biocide. A molecular level understanding of the interface was obtained using attenuated total reflectance Fourier transform infrared, Raman, and X-ray photoelectron spectroscopies, alongside density functional theory calculations. These reveal that the linker molecules dock the SA molecules at the surface via a 1:1 complexation interaction. Furthermore, each 1:1 complex acts as a nucleation point onto which multiple stacks of the biocide are subsequently stabilized via a combination of H-bonding and π-πstacking interactions, thus significantly enhancing SA uptake at the interface. The antimicrobial activity of these surfaces against model Gram-negative and Gram-positive bacteria represented by Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis is demonstrated by a log 6 reduction of planktonic bacterial populations and an efficient anti-biofilm activity at the surface.

Original languageEnglish
Pages (from-to)4801-4811
Number of pages11
JournalACS Applied Bio Materials
Issue number11
Publication statusPublished - 18 Nov 2019
Externally publishedYes


  • antimicrobial surfaces
  • functionalized PDMS
  • medical device materials
  • salicylic acid
  • n/a OA procedure


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