Team:FAU Erlangen/Notebook

iGEM Erlangen


Biology


Chemistry/Physics

Zn(NO3)2 x 4 H2O, Zn(Ac)2, Cetyltrimethylammonium bromide (C16TAB), NaOH and KOH were purchased from Sigma-Aldrich. All experiments were carried out in ultrapure water. The synthesis of ZnO microflowers is similar to a synthesis performed by Zhang et al. (2004). 0.5 g of Zn(Ac)2 were added to 110 mL of a saturated C16TAB aqueous solution under stirring. After 10 min of stirring, 10 mL of a 2 M NaOH aqueous solution were added under stirring, resulting in a white aqueous solution maintained at 110 °C for 1 h under reflux. The white solid was centrifuged, washed with distilled water and ethanol until no foam was present after shaking. Finally, the white sediment was dried at 60 °C under vacuum.

The mineralization process was related to a process developed by Umetsu et al. (2005) and used by Tomizaki et al. (2012) to produce ZnO nanofibers. A 0.1 M zinc nitrate solution was mixed with the same volume of 0.2 M KOH. The produced Zn(OH)2 was sonicated and centrifuged. The supernatant was discarded and the sediment was resuspended with distilled water of the same volume. Using the 0.1 M Zn(OH)2 stock solution, solutions with a concentration of 0.02 M and 0.05 M were prepared. Solutions of 0.1 M, 0.05 M and 0.02 M were added to the freshly prepared biofilms (for preparation description, see the biological part). After three days, the biofilms were separated from the solution, washed with distilled water and dried at room temperature.


References

  • Tomizaki, K. Y., Kubo, S., Ahn, S. A., Satake, M., & Imai, T. (2012). Biomimetic alignment of zinc oxide nanoparticles along a peptide nanofiber. Langmuir, 28(37), 13459-13466. doi: 10.1021/la301745x


  • Umetsu, M., Mizuta, M., Tsumoto, K., Ohara, S., Takami, S., Watanabe, H., ... & Adschiri, T. (2005). Bioassisted Room‐Temperature Immobilization and Mineralization of Zinc Oxide—The Structural Ordering of ZnO Nanoparticles into a Flower‐Type Morphology. Advanced Materials, 17(21), 2571-2575. doi: 10.1002/adma.200500863


  • Zhang, H., Yang, D., Ji, Y., Ma, X., Xu, J., & Que, D. (2004). Low temperature synthesis of flowerlike ZnO nanostructures by cetyltrimethylammonium bromide-assisted hydrothermal process. The Journal of Physical Chemistry B, 108(13), 3955-3958. doi: 10.1021/jp036826f