Tailoring the surface and rheological properties of gelatine-based hydrogel films via indirect cold plasma treatment for engineering applications

A novel and efficient cold plasma-based approach is described for upgrading heat-sensitive biomaterials, which are unable to be exposed to plasma environments. The indirect plasma treatment was applied to gelatine-hydrogel films and shown its capability to induce changes in their wettability and increase the concentration of chemical functionalities. The mechanical properties of the native hydrogels can be tuned by tailoring them using the proposed methodology. Wetting behaviour of the films is discussed in terms of SFE values obtained by two different theoretical approaches, the contact angle hysteresis and the acid-base, LVDW. Plasma treatment induced a drastic rise in the hydrophilicity character and surface roughness of the hydrogels. Dynamic oscillatory measurements showed unusual mesoscopic variations in the plasma-treated films. Texture analysis revealed noticeable modifications of hardness, springiness, cohesiveness, gumminess, and adhesiveness after the plasma activation. The gas plasma (air, Ar and O2) significantly affected the degree of hydrogel functionalization. The development of new strategies to achieve optimal design would enable new engineering applications for this important type of biomaterials.