Microscopy techniques applied for monitoring the development of aquatic biofilms

Using an experimental setup based on packed bed reactors (filled with glass beads) supplied with water from a groundwater source, the suitability of different microscopic techniques for biofilm monitoring was evaluated. Confocal microscopy is the most versatile, applicable and suitable technology for biofilm study and even provides information about the main surface and height parameters. Nevertheless, the wide field images obtained with the confocal perfilometer, combined with the super-long work distances of the objectives used, facilitate and improve the observation of non-flat surfaces. Moreover, the utilization of a white light source does not affect the viability and the activity of microbial cells. Confocal perfilometry can be the choice for a non-invasive monitoring of the microbial colonization of non-flat surfaces, such as the glass beads. Other techniques such as the Environmental Scanning Electron Microscopy (ESEM), cryoembedding and cryosectioning can be useful as complementary tools to help in the characterization of the structure and architecture of mature biofilms.