Study on the atmospheric cold plasma (ACP) treatment of zein film: Surface properties and cytocompatibility

The cell adhesion and proliferation of zein-based biomaterials in cell culture application are limited by the strong hydrophobic surface with low surface energy. In this study, atmospheric cold plasma (ACP) was developed as a modification approach in enhancing the surface hydrophilic and cytocompatibility of zein films. The results indicated that water contact angles decreased from 72.85° (untreated) to 47.43° under the voltage of 100 V. The improvement of the surface free energy (SFE) was mainly attributed to the polar component rather than dispersive component. X-ray photoelectron spectroscopy (XPS) results indicated the change of surface physicochemical properties was mainly due to the partially transformation of long-chain aliphatic hydrocarbons (CH and/or CC) to oxygen- and nitrogen-containing bonds (CO, CO and CN). Furthermore, the content of secondary structure demonstrated β-turn and α-helix were transformed into β-sheet and random coil after ACP treatment. Combining with the cell experiment results, plasma treatment could significantly improve the adhesion rate and proliferation activity of C2C12 cells on zein films. With better cytocompatibility, the potentials of zein in tissue engineering scaffold could be readily exploited.