Adhesive behavior of DNA molecules on silicon wafers treated by argon and oxygen plasma

The adhesion of Deoxyribose Nuclei Acid (DNA) on an electrode surface such as silicon is a key issue in the sensitivity of DNA chips, in order to maximize the DNA concentration on the electrodes of DNA chips and increase the detected signal, the chip should have good adhesion of DNA to its electrodes. In our study, several pieces of silicon wafer were treated by argon and oxygen plasma, respectively. We analyzed the DNA content on the different silicon surfaces using the X-ray photoelectron spectroscopy (XPS). The results indicate that the content of DNA molecules adhered on the silicon surface treated with an oxygen plasma is higher than that on the surface treated with an Ar plasma. This can be interpreted in terms of the interaction of parasitic charges and van der Waals forces on silicon oxide surfaces.