Real-time optotracing of curli and cellulose in live Salmonella biofilms using luminescent oligothiophenes

Biofilm formation can be studied as it happens using chemicals that fluoresce at different wavelengths as their conformation changes. However, understanding the dynamics of biofilm formation has been hindered by the lack of suitable research tools. Agneta Richter–Dahlfors and colleagues at the Karolinska Institutet in Sweden, with co-workers at Linkoping University, addressed this limitation using chemicals called oligothiophenes. The optical properties of these “chemical chameleons” vary as their conformation is affected by their environment. Changes in oligothiophene fluorescence monitored the formation of two key protein and polysaccharide components of the extracellular matrix of biofilms. The scope of the technique was demonstrated by characterizing biofilms of various forms of Salmonella bacteria. The work also revealed wider applications by studying cellulose formation inside cells of higher organisms. The researchers believe their ‘opto-tracing’ procedure could redefine biofilm research.