Team:Nanjing-China -

What are biosensors?

- Devices that use a biological component such as enzymes, antibodies, sub-cellular components, and microorganisms to obtain information.


What are biosensors for?

- They are designed to detect small amounts of chemical, or to report physiological and biochemical characteristics of a sample.

What’s the difference between biosensors and whole-cell sensors?

-A whole-cell sensing system depends on the integrity of a cell or a microorganism.
-It includes a series of biochemical reactions inside the cell.

Formaldehyde, hydrogen sulfide and hydrogen are three common gases that can pose great danger to our lives. Formaldehyde and hydrogen sulfide are venomous substances released from decoration materials and decayed remains, while formaldehyde is known to be human carcinogen. Hydrogen is widely used in industry and laboratories, which is a potential safety threat to factory and lab crews owing to its flammability and explosion hazard. However, traditional methods for detecting these gases are mainly based on irreversible redox reactions in complicated and expensive devices with short life spans, whereas it has been reported that whole-cell bacterial biosensors have major advantages over traditional analyses with regard to specificity, sensitivity and portability.

Our team attempts to develop a whole-cell system detecting formaldehyde, hydrogen sulfide and hydrogen. We have managed to transfer gene clusters encoding gas-specific translational suppressors or activator into E. coli to respond to different gas molecules by up regulation of specific downstream genes. In order to visualize the gases’ existence and concentration, genes coding for fluorescent proteins are also inserted in the expression system after the promoter influenced by the suppressor or activator. At present, results have shown sensibility at a µM level.

As long as proper containers are designed, we will be able to construct portable whole-cell gas sensors by which users can perform instant on-site monitoring possibly with higher sensitivity, accuracy and stability but lower costs.