Graphene‐dispersed silane compound used as a coating to sense immunity from biofilm formation

Biofilm is a substance that contains organic polymers. It is derived from bacteria, produces slime and forms on material's surfaces. Therefore, it is important to properly evaluate biofilm formation using several types of sensors. Since biofilm forms easily on graphene, it is possible for graphene to serve as a sensor for biofilm formation. In the past, graphene's sensitivity to biofilm formation was confirmed by using CVD (chemical vapour deposition) graphene and by using the tape‐exfoliation method. However, the CVD method was expensive and required special equipment. On the other hand, the exfoliation method was not so expensive, but the precision and reproducibility for graphene formation were problematic. In this experiment, silane‐based resin, with dispersed graphene, was coated on a substrate. This coated substrate can easily be used as a sensor and is an inexpensive way to promote biofilm formation. Glass was used as the substrate, for which various samples were prepared using different concentrations of dispersed graphene. Biofilms formed on the specimens’ surfaces were analysed by using Raman spectroscopy and the crystal violet staining method. The results showed that biofilm formation capability increased with the concentration of dispersed graphene. We confirmed that the sensitivity was evaluated by the colour value for stained surfaces by crystal violet.