Team:Bielefeld-CeBiTec/Results

Results Overview
This is nanoFactory - a combined system to clean up mining drainage and to produce nanoparticles.

Dual Use

We analyzed the awareness of Dual Use and Dual Use Research of Concern issues through a nationnal and an international survey. Both surveys revealed the lack of unified definitions, insufficient education, and failed science communication as major problems. To improve the situation and to prevent restrictions on free research, we increased awareness through improved science communication, appealed to the science community, and provided open source material for education of scientists.

Modeling

Modeling contributed to several project parts. One modeling approach identified lethal metal ion concentrations and led to the construction of a ROS reducing system to improve the tolerance towards metal ions.

Promoter Collection

Since there is a shortage of reliable information about promoter strengths, we tested a promoter and RBS library to identifiy the appropriate combination for our project. Therefore, we constructed a plasmid backbone, which enables reliable promoter strength measurement through normalization based on a second reporter encoded in the backbone. It has not escaped our notice that this system could be applied by further iGEM teams to characterize any promoter sequence of interest.

Toxicity

Metal ions have a toxic effect on Escherichia coli cells. We identified critical concentrations for our experiments and developed several methods to reduce ROS.

Accumulation

To increase the nanoparticle yield, we cloned and characterized dedicated metal ions importers. We investigated the specifcity towards their respective ions and the influence on the growth.

Silencing

We designed and assembled vectors for assessment and expression of siRNAs. We used our software to design suitable siRNAs and developed an improved vector set for experimenntal validation.

Nanoparticles

We were able to enhance iron nanoparticle formation by overexpressing ferritin in Escherichia coli. Furthermore, we developed a mutated variant of the human ferritin to produce gold and silver nanoparticles.

Reactor

We designed and printed a customized cross-flow bioreactor to filter huge amounts of mining drainage while accumulating metal ions. Through iterated feedback from our modeling we improved our prototype and developed an improved bioreactor to facilitate application of our system for the cleaning of mining drainage.

Proof of Concept

During our project we were able to demonstrate accumulation of metal ions in Escherichia coli, while increasing the tolerance towards such ions. We engineered ferritin to enable iron, silver and gold nanoparticle formation. Furthermore, we demonstarted that nanoparticles could be used to print conductive paths.