Atmospheric pressure plasma polymers for tuned QCM detection of protein adhesion

•Plasma polymerization reaction at atmospheric pressure would be considered as a simple and viable method for the preparation of QCM bioactive surfaces.•The amount of adsorbed proteins can be controlled by introduction of PEG precursors in the plasma discharge during the preparation of plasma PS polymers.•Variable frequency changes were demonstrated for complete protein saturation for the two structurally and dimensionally different ConA and BSA proteins.

Our efforts have been concentrated in preparing plasma polymeric thin layers at atmospheric pressure grown on Quartz Crystal Microbalance—QCM electrodes for which the non-specific absorption of proteins can be efficiently modulated, tuned and used for QCM biosensing and quantification. Plasma polymerization reaction at atmospheric pressure has been used as a simple and viable method for the preparation of QCM bioactive surfaces, featuring variable protein binding properties. Polyethyleneglycol (ppEG), polystyrene (ppST) and poly(ethyleneglycol–styrene) (ppST–EG) thin-layers have been grown on QCM electrodes. These layers were characterized by Atomic Force Microscopy (AFM), Contact angle measurements, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The plasma ppST QCM electrodes present a higher adsorption of Concanavalin A (ConA) and Bovine Serum Albumin (BSA) proteins when compared with the commercial coated polystyrene (ppST) ones. The minimum adsorption was found for ppEG, surface, known by their protein anti-fouling properties. The amount of adsorbed proteins can be tuned by the introduction of PEG precursors in the plasma discharge during the preparation of ppST polymers.