Electrochemically activated laser-induced graphene coatings against marine biofouling

Abstract

Biofouling can severely impact the function of devices in contact with sea- or brackish water. Laser-induced graphene (LIG) was previously discovered to resist bacterial attachment and when electrochemically activated to reduce their viability. Here we investigated the suitability of LIG and electrochemically activated LIG to counteract the attachment of marine organisms in high salinity media. We fabricated LIG on poly(ether)sulfone with optimized electrical conductivity and varied the wettability of the surfaces using atmospheric plasma and chemical modification. The superhydrophilic and superhydrophobic LIG surfaces were challenged with the marine bacterium Cobetia marina in a dynamic attachment assay, which showed that superhydrophobic LIG coatings are capable to resist bacteria accumulation. An extended biofilm growth experiment revealed that even unfunctionalized LIG coatings outperformed control gold coated glass surfaces modified with 1-dodecanthiol after 36 h by showing a reduced biofilm coverage. Electrochemical measurements performed under static conditions showed reduction of bacteria accumulation for potentials above +1.4 V. This effect was attributed to the formation of H2O2, which was detected at µM levels. The results underline the promising potential of LIG surface modification as method to counteract marine fouling.