Cellock Holmes - A Case of Identity

• 2D Biosensor
• REACh Construct
• Galectin-3
• WatsOn

"What's living on the table in front of you?" seems to be an easy question to answer: microoganisms. However, "Which microorganisms are there?" is not such a trivial question anymore, especially in environments where you only want to have a non-pathogenic microflora or no microorganisms at all, such as lab spaces or health care institutions.

Our project Cellock Holmes solves this case of identy.

Cellock Holmes encompasses our 2D biosensing technology with which can detect bacteria on solid surfaces. Cellock Holmes is mainly devised to overcome the drawbacks of existing techniques and aims for a faster, inexpensive, open source, mobile and an easy to handle detection method.

We demonstrate the proof-of-concept for Cellock Holmes by detecting an opportunistic pathogen Pseudomonas aeruginosa. This gram-negative prokaryote infects patients with open wounds and burns as well as immunodeficient people. P. aeruginosa cells use quorum sensing to communicate with each other by secreting autoinducers into their environment. Using a Synthetic Biology (SynBio) approach, our team engineered sensor cells, so-called Cellocks, that are able to detect the native autoinducer of P. aeruginosa and elicit a distinct fluorescence signal. Further, the response time of our sensor cells has been highly enhanced by the use of our special REACh construct.

While Cellocks are specifically designed to detect P. aeruginosa, with a modular composition of our genetic device, it is possible to easily engineer Cellocks to detect autoinducers of other bacteria. Even more flexibility is introduced when using our alternative molecular approach using Galectin-3.

Hand in hand with the biological side of our project, our IT crew built the WatsOn , our measurement device. WatsOn is able to read and analyze the fluorescent signal emitted by the 2D biosensor. For an Open access, we publish DIY construction manual and technical details of our devices.

To learn more about the different parts of our 2D biosensor, click on the respective panels on the right.

The OD/F Device - A Project Spin-Off

• OD/F Device

Originally planned to be used as our own measurement device in the Interlab Study, our IT division developed our OD/F Device. This device can measure optical density and fluorescence of a liquid sample. It is used in the same way as a regular spectrophotometer: A plastic cuvette is filled with sample solution and inserted into the device. The values of optical density and fluorescence are subsequently displayed to the user.

The target group for our device are low-budget institutions such as schools, community labs and the bio-hacker scene. The OD/F device is designed in accordance with the open source principle and all technical details as well as construction manuals are published on our wiki.