Adsorption of a PEO–PPO–PEO triblock copolymer on metal oxide surfaces with a view to reducing protein adsorption and further biofouling

Abstract

Biomolecule adsorption is the first stage of biofouling. The aim of this work was to reduce the adsorption of proteins on stainless steel (SS) and titanium surfaces by modifying them with a poly(ethylene oxide) (PEO)–poly(propylene oxide) (PPO)–PEO triblock copolymer. Anchoring of the central PPO block of the copolymer is known to be favoured by hydrophobic interaction with the substratum. Therefore, the surfaces of metal oxides were first modified by self-assembly of octadecylphosphonic acid. PEO–PPO–PEO preadsorbed on the hydrophobized surfaces of titanium or SS was shown to prevent the adsorption of bovine serum albumin (BSA), fibrinogen and cytochrome C, as monitored by quartz crystal microbalance (QCM). Moreover, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry were used to characterize the surfaces of the SS and titanium after competitive adsorption of PEO–PPO–PEO and BSA. The results show that the adsorption of BSA is well prevented on hydrophobized surfaces, in contrast to the surfaces of native metal oxides.

Keywords:

• quartz crystal microbalance (QCM)
• PEO–PPO–PEO
• biofouling
• surface modification
• metal oxide
• protein adsorption

Acknowledgements

The authors thank Michel Genet for the discussion of XPS results and Dr Kevin McEvoy for QCM training and discussion of protein adsorption results. The research leading to these results has received funding from the European Community’s 7th Framework Programme (FP7/2007–2013) under grant agreement No. 238579. Funding by the Belgian National Foundation for Scientific Research (FNRS) and by BELSPO (Interuniversity Attraction Pole Program) is acknowledged also.