Functional nanothin films plasma-deposited from 2-isopropenyl-2-oxazoline for biosensor applications

Plasma polymers derived from oxazoline precursors present a range of versatile properties that is fueling their use as biomaterials. However, coatings deposited from commonly used methyl and ethyl oxazoline precursors can be sensitive to the plasma deposition conditions. In this work, we used various spectroscopic methods (ellipsometry, x-ray photoelectron spectroscopy, and time of flight secondary ion mass spectrometry) and cell viability assays to evaluate the transferability of deposition conditions from the original plasma reactor developed by Griesser to a new wider, reactor designed for upscaled biosensors applications. The physicochemical properties, reactivity, and biocompatibility of films deposited from 2-isopropenyl-2-oxazoline were investigated. Thanks to the availability of an unsaturated pendant group, the coatings obtained from this oxazoline precursor are more stable and reproducible over a range of deposition conditions while retaining reactivity toward ligands and biomolecules. This study identified films deposited at 20 W and 0.012 mbar working pressure as being the best suited for biosensor applications.