Team:ZJU-China/Project/GhostSensor/Perspectives

Ghost Sensor: Perspectives

Our ghost sensor platform can not only be used to detect proteins, it can also be used to specifically clear proteins in solution and achieve long-term storage of proteins.

Magic strip

For the second set of inner-membrane scaffolds, two parts of β-lactamase were fused to the periplasmic ends. When 19-mer and 25-mer biotin-modified aptamers are added to the solution and thrombin is present, aptamers act like a bridge linking streptavidin-fused membrane scaffolds and thrombin. In this way, two molecules of membrane scaffolds are pulled together and the two residuals of β-lactamase will meet each other again to become an integrity part with enzymatic activity. This activity can be detected by commercial β-lactamase testing strips, with a total preparation time of about 10 min.

Ghost cleaner

We can deliberately deplete a specific kind of protein from solution with an antibody pull down assay, but it is too expensive to perform and need a great amount of antibodies. Using ghost sensor platform is good alternative. All we have to do is adding bacterial ghost into the solution in which streptavidin is fused to inner-membrane scaffold. Then aptamers specific to the target are included to the solution. Bacterial ghosts act like a giant magnet, suck large amounts of targeted molecules into their bodies. At last, we can centrifuge to precipitate bacterial ghosts together with targeted molecules. Because the size of holes in the bacteria surface can be adjusted by controlling the concentration of magnesium during induction, our ghost sensor platform can in principle clear a variety of targets ranging from small chemicals to viruses.

Ghost storage

In our team’s safety section, we tried to construct CaCO₃ bacterial shell to elongate E.coli storage time. This technique can also be applied to ghost sensor platform. When targeted proteins are precipitated from the solution with bacterial ghost, we build a shell around our E.coli to completely seal the tunnels. In this way, proteins are insulated from harsh outside environment and kept relatively safe bathing the buffer system inside the shell. We hope that this technique could tackle the problem that proteins cannot be long-term stored in room temperature due to proteinase in the environment.