New approach to TERS probe coating enables chemical imaging of liquid-immersed surfaces with nanoscale spatial resolution.

Despite the extensive use of polyetheretherketone (PEEK) in biomedical applications, information about cell adhesion on this biomaterial is limited. This study focuses on PEEK tuned by argon plasma treatment with the aim to enhance its wettability and cytocompatibility. Changes in surface properties of the plasma treated surface were studied in relation to the adhesion, proliferation and metabolic activity of mouse fibroblasts (L929) and human osteoblast (U-2 OS) in vitro. Moreover, the expression profiles of two proteins (talin 1 and vinculin) responsible for cell adhesion, were determined at 2 time points in dependence on the PEEK treatment. Plasma treatment increased the surface wettability of PEEK and led to changes in its surface morphology and chemistry. The XPS method showed a decrease in carbon content and augmentation of oxygen concentration with increasing effect of the plasma. Plasma treatment of PEEK significantly enhanced cell adhesion, proliferation and metabolic activity of both cell lines when compared to pristine PEEK. Moreover, special attention was devoted to filopodia of L929 cell adhered on PEEK studied by means of scanning electron microscopy. The most abundant filopodia were present on PEEK plasma treated for “longer” times.