The development of in vitro-based biosensors for the detection of pathogenic biofilms

Ke Yan Wen1,2, James Chappell3, Kirsten Jensen1,2, Jane Davies4,5, Alain Filloux6, Paul
Freemont1,2

1Centre for Synthetic Biology and Innovation, Imperial College London, UK

2Department of Life Sciences, Imperial College London, UK

3School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA

4Department of Gene Therapy, Imperial College London, UK

5Royal Brompton & Harefield NHS Foundation Trust, London, UK

6Medical Research Council Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, UK

Microbial biofilms are cooperative cell communities that coordinate behaviour and gene expression at the population level. They are extremely difficult to disperse with antimicrobial agents due to their ability to produce a protective extracellular matrix. Subsequently they
pose a major challenge in healthcare and industrial settings. For example, cystic fibrosis patients often suffer chronic lung infections that are due to biofilm colonisations of Pseudomonas aeruginosa. Rapid detection of this bacterial phenotype could assist greatly in preventing and treating the establishment of chronic infections. We have developed an in vitro biosensor to detect the presence of P.aeruginosa quorum-sensing molecules. It is based on the expression of a DNA template within a cell-free system, to produce both the detection module and a measurable output in a single reaction. Our use of cell-free coupled
transcription and translation systems as a biosensor platform provides an alternative to whole- cell chassis, which offers advantages in terms of simplicity, detection time and biosafety.

After establishing a proof of principle for the detection of the presence of P. aeruginosa biofilms using this biosensor, we are currently focused on testing clinical samples from cystic fibrosis patients. This approach will allow us to determine the potential for this method as a research and diagnostic tool for pathogenic biofilms.