Team:Shanghaitech/Collaborations/ustc
Reagent share to USTC
iGEM team USTC is working on the CdS based bio-film. They want to know whether CdS nanoparticles can increase the cathode-current as expected. A key component for one of their experiments requires CdS quantum dots, which they cannot generate by themselves.
We provided them the CdS quantum dots sample. They added our sample into the culture to assist bio-film formation onto the surface of a graphite electrode. Theoretically, CdS quantum dots would be attached to the surface of the bacteria as the bio-film was formed.
Figure 6. Preparation for the bio-film. (need more figure legends here if you want to show this pic. It’s not clear what are in the picture for people who do not work on bio-film)
Figure 7. The hardware that controls the exposing light during bio-film formation.
Then, we put the cathode running and monitored the current. As you can see in figure 8, the strain pMC, which were co-expressing Mtr CAB and Ccm A-H, had a stronger cathode current than the WT strain before the light was given, which perfectly repeated the result we have done in the conduction system section. After the current was stable, we began to give light to the system. The light’s wavelength is 455 nm and the source is a LED light bought from an online shop. The strain pMC with CdS quantum dots on it responded to the light stimulate. It had a stronger current than it was before the light was given. However, those strains without CdS quantum dots on it did NOT respond to light stimulate. Especially, for the pMC group without CdS quantum dots on it, it did NOT have any current change after we give light to the system, which excludes the possibility that the current change was resulted from the Mtr CAB proteins or the Ccm A-H protein. Moreover, after we stopped the light, the current got back to the level it was before we gave the light.
Figure 8. CdS canincrease cathode current.
CdS quantum dots can speed up the electrons transfer process, pumping more electrons from the electrode to the bacteria in the same time utilizing light energy. This may results from the CdS quantum dots’ property as a semiconductor.
In summary, CdS quantum dots we provided can increase the cathode current with its semiconductor property in team XX’s experiments. Thus, this collaboration is fruitful with a new photosynthesis system developed, where they can further increase the speed of the electron transfer process that leads to the improvement of bio-film synthesis.
Reference:
[1] Chu, L., Ebersole, J. L., Kurzban, G. P., & Holt, S.C. (1997). Cystalysin, a 46-kilodalton cysteine desulfhydrase from Treponemadenticola, with hemolytic and hemoxidative activities. Infection and immunity,65(8), 3231-3238.
[2] Wang, C., Lum, A., Ozuna, S., Clark, D., & Keasling,J. (2001). Aerobic sulfide production and cadmium precipitation by Escherichiacoli expressing the Treponema denticola cysteine desulfhydrase gene. Applied microbiology and biotechnology, 56(3-4), 425-430. [3] Sakimoto, K. K., Wong, A.B., & Yang, P. (2016). Self-photosensitization of nonphoto syntheticbacteria for solar-to-chemical production. Science, 351(6268), 74-77.
