2D Biosensor

Principle of Operation

Cellock Holmes is devised based upon a SynBio approach comprised of a two-dimensional biosensor and a measurement device. The two-dimensional biosensor is designed to recognize quorum sensing molecules secreted by the pathogen cells and generate a distinct fluorescence signal, while the measurement device is designed to recognize and analyse the produced signal.

A Novel Molecular Approach

For our biosensor, our team genetically modified E. coli cells to be able to elecit a fluorescent response to autoinducers produced by the pathogen Pseudomonas aeruginosa during quorum sensing. In the case of P. aeruginosa, these autoinducers are N-3-oxo-dodecanoyl-L-homoserine lactone, or 3-oxo-C-12-HSL for short. The quorum sensing system of this pathogen contains the LasR activator which binds 3-oxo-C-12-HSL, and the LasI promoter, which is activated by the LasR-HSL complex. Both LasR activator and LasI promoter are available as BioBricks [http://parts.igem.org/Part:BBa_C0179 C0179] and [http://parts.igem.org/Part:BBa_J64010 J64010].

As a reporter gene, we use GFP. However, expression of GFP is not simply controlled through the LasI promoter activity in our approach. Instead, our sensor cells contain a constitutively expressed fusion protein consisting of GFP and a dark quencher, and an HSL-inducible protease.

Add: [Fig. 1: Scheme of our molecular approach]