We have developed and are testing nanocoatings composed of a chitosan matrix used as a base for nanoparticle inclusions. The coatings are non-toxic and work by 1) local generation of reactive oxygen species (ROS) that destroy microbes, or 2) by forming a 'slippery' surface that makes bacterial attachement difficult.
We assess anti-biofouling effects by calculating the volume of the biofilm growing on the coated surface. This is achieved via depth imaging of the biofilm using Optical Coherence Tomography (OCT).
OCT is akin to Ultrasound in that it generates images from backscattered reflections (but using light instead of sound). Compared to traditional microscopy methods, OCT offers a high degree of automation and the ability to quickly 3D-image the full experimental surface without subsampling.
The method is non-destructive to the sample that is not stained and is only submerged in physiological saline during imaging.
Image credit: Rasmus Juul Jensen.
We use confocal microscopy and specific dyes to measure the viability of cells within the biofilm. An effective coating may have a large proportion of non-living bacteria.
The broader microbial community structure as well as its off-flavour production potential is analysed using DNA methods.
Image credit: By CFCF under Attribution 4.0 International (CC BY 4.0) ( Creative Commons — Attribution 4.0 International — CC BY 4.0 ) (with modification).
