2D Biosensor

With our 2D biosensor technology we are able to detect the pathogen Pseudomonas aeruginosa on solid surfaces. The sensor system is comprised of two distinct but inseparable modules, a biological part and a technical part:

• Sensing chips containing Cellocks, our engineered detective cells that fluoresce in the presence of the pathogen, make up the biological part of Cellock Holmes.
• Our measurement device WatsOn and the complementary softare Measurarty complete our sensing technology on the technical side.

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 to generate a distinct fluorescence signal, while the measurement device is designed to recognize and analyse the produced signal. To overcome the limitation of our REACh construct to bacteria that secrete autoinducers, we developed an alternative detection method (Galectin-3 construct), which is based on tagging cells with a fluorescent reporter.

[graph quorum senising]

Our sensor cells are immobilized in agar chips. To make the chips, we mix the sensing cells, also known as Cellocks, with liquid LB agar. In the course of our project, we designed a casting mold specifically for the production of our agar chips. When the agar has cooled down, the chips are cut out of the mold and are ready to use. Storage of the readily usable sensor chips is possible for 2 days at 4 °C when using LB medium or for 5 days if TB-medium is used. If you want to know exactly how our chips are manufactures, you can read up on more details in our Protocols section.

Application of WatsOn for investigation of solid surfaces.

The application of Cellock Holmes for detection of P. aeruginosa cells is simple: fist, a sampling chip is placed on a hard surface that is potentially contaminated with the pathogen. Second, the chip is put onto one of our sensor chips. Subsequently, the two layered chip-stack is put into a petri dish, which is inserted into our measurement device WatsOn for evalutation.

Mode of action inside WatsOn.

Inside WatsOn the chips are incubated at 37 °C and populations os microorganisms on the chip used for sampling start to multiply. In contrast to other microorganisms p. aeruginosa secrets an increasing number of autoinducers () when multiplying The chips can be illuminated with blue light at any time, while WatsOn takes a picture of the chip. The software Measurarty then analyzes any fluorescent signal. Depending on the intensity of the signal and the size of the spot, Cellock Holmes can calculate concentration and distribution of P. aeruginosa on the sampled surface.

Achievements

What was done so far

Testing our sensor Chips with a Platereader

Detecting the 3-oxo-C₁₂ HSL with K131026 in our sensor chip with WatsOn.

Detecting Pseudomonas aeruginosa with K131026 in our sensor chip with WatsOn.