Antibacterial properties of poly(dimethylsiloxane) surfaces modified with graphene oxide-catechol composite

We have prepared the graphene oxide (GO)- a catechol derivative -dopamine methacrylamide monomer (DMA) composite modified poly (dimethylsiloxane) (PDMS) surfaces by pi - pi stacking of 1-pyrenebutyric acid on the GO and dopamine surface. PDMS substrates were first oxidized by plasma to transform the Si-CH3 groups on their surfaces into Si - OH groups. Subsequently, aminopropyltriethoxysilane (gamma-APS) was immobilized onto the PDMS-OH surface, and 1-pyrenebutyric acid (PA) was then bonded covalently onto the PDMS-gamma-APS surfaces by the amidation reaction. Finally, PDMS-GO-DMA surfaces were prepared by modifying GO-DMA composites onto the PDMS-PA surface by pi - pi stacking between 1-pyrenebutyric acid and GO-DMA. Various characterization techniques, including contact angle measurements, attenuated total reflection infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS), were used to ascertain the successful prepared the PDMS-GO-DMA surface. The antibacterial ability of PDMS-GO-DMA surface was investigated by the classic colony and visible spectrophotometry methods. The results showed that PDMS-GO-DMA surface displayed antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria compared with native PDMS surface. Furthermore, we studied the biocompatibility of the PDMS-GO-DMA by culturing the cell lines (HepG2 and A549) on the PDMS-GO-DMA surface which exhibited excellent biocompatibility. Additionally, our results present possible uses for the PDMS GO-DMA surface as antibacterial functional surfaces in biomedical microdevices applications.