How to Confer a Permanent Bio-Repelling and Bio-Adhesive Character to Biomedical Materials through Cold Plasmas

Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) of polyethylene oxide-like (PEO)-like coatings represent a successful strategy to address cell-behavior on biomaterials. Indeed, one of the main drawbacks of organic and hydrophilic films, like PEO-like ones, often consists in their poor adhesion to the substrate, especially in biological fluids where the biomaterial is required to operate. In this paper, low pressure (LP) and aerosol-assisted atmospheric pressure (aerosol-assisted AP) PE-CVD of PEO-like coatings is compared. The stability of the two different classes of coatings was investigated, both in water and in the cell culture media, during cell culture experiments. The obtained results show that, when deposited at atmospheric pressure (AP), the adhesion of the PEO-like coatings to the substrate has to be granted by an intermediate gradient layer. This interlayer can match the properties of the substrate with that of the topmost coatings, and, in turn, can dramatically improve the coating's stability in complex biological fluids, like the cell culture medium. An accurate modulation of the experimental conditions, both at LP and AP, allowed control of the film chemical structure and surface properties, to permanently promote or discourage the cellular adhesion on the surfaces of biomaterials.