Partnership

We formed a close partnership with team NWU-CHINA-A. The two teams first found each other when NWU-CHINA-A was experiencing problems with modeling and hardware, and their PI recommended our team to them. At that time we were studying the harm of heavy metals to health, while they involved heavy metals because their project focused on intestinal bleeding detection, and heavy metals have significant harm to the intestine.

After a meeting, we quickly settled on the content of our collaboration. We drew members from both teams and formed a small team for cooperation. We helped them with all the mathematical modeling work, as well as the hardware prototype which was suitable for both teams. In addition, we enriched the NWU parts library together. Our team was short on external connections and arts. So the NWU-CHINA-A team invited us to join the Gut Alliance for communication with more iGEM teams and helped us design the animation of our logo. We also cooperated on educational activities such as giving lectures to Beijing No. 22 Middle School.

We held routine conversation meetings once a week and further discussed our projects at any time needed. In the process, both of our projects benefited a lot, and the projects' shaping process was also partially shared. Finally, we made the same hardware prototype based on the continuing changes in both teams’ project needs.

Model

The purpose of NWU-CHINA-A’s modeling work is to compare the difference between the conventional cultivation hardware and their new hardware from the bacterial growth status by measuring the bacterial concentration. We carried out their modeling work for them by analyzing their data to make conclusions regarding their hardware. We applied regression in multiple ways to analyze the data, and the two teams collaborated closely in trying to draw meaningful conclusions from our analysis. They eventually succeeded in learning new things about their hardware.

Both teams closely worked together in undergoing two complete iterations of the Engineering Cycle during our cooperative modeling for NWU-CHINA-A’s hardware testing. In the process, NWU-CHINA-A conducted the experiments, while Shiran Yuan from DKU_China was in charge of all modeling work.

Engineering Cycle 1

Design

Our cooperation for hardware testing began with a short meeting. During the meeting, NWU-CHINA-A team members introduced their needs and Shiran Yuan from DKU_China introduced some basic knowledge and concepts of modeling to NWU-CHINA-A to facilitate communication. Eventually, the two teams jointly selected the parameters for testing and completed the experimental design.

Build

The experiment involved testing the ODs of cultivated strains in NWU-CHINA-A’s new hardware and conventional hardware respectively, then comparing the growth curves of the strains to see if the NWU-CHINA-A hardware works properly.

Test

The results of the experiment are as follows:

The relation between the control group data and the experimental data is as follows:

The residual plots are as follows:

Learn

We analyzed the results of the first experiment together. The experimental results were enough to indicate that, despite the effects being slightly worse compared to conventional methods, the NWU-CHINA-A hardware works well. However, the data indicated that the error is relatively large. Eventually, we concluded that:

  1. During calibration, the concentration of strains in the liquid used for calibrating was later found to be inconsistent, therefore indicating that the experimentally tested OD might deviate from the actual values.
  2. Due to the problem that some of the NWU-CHINA-A team members in charge of operating the experiment lack experience, the operational errors in the experimental results are large.

Engineering Cycle 2

Design

Learning from the previous cycle, the experimental design was adjusted. The calibration process was standardized, and the operation process was carried out by only one person to minimize operational errors.

Build

The basic experimental design stayed the same.

Test

For experimental results and quantitative analysis, please refer to NWU-CHINA-A’s Model page.

Learn

This time, from modeling we learned two useful results which indicate the success of our experiment:

  1. The growth curve of the strains fits perfectly with the logistic growth model (theoretical prediction).
  2. The NWU-CHINA-A hardware works well, and its difference in performance from the conventional hardware is statistically insignificant.

Hardware

Our project needs a hardware for safe sample holding in experimentation and future potential field sampling. Team NWU-CHINA-A’s project requires an auxiliary culture device. After careful communication, we found that we can design a hardware for meeting the needs of both teams.

Team NWU-CHINA-A gave their requirements,

  • A sample-holding device.
  • It may be a bag or a box, to put the dry powder of the culture medium in it.
  • This device could be put into the incubator and biological oscillator.

The requirements of our project,

  • Easy to carry.
  • A box with a lid.
  • Leakproof.
  • Enough space for the experimental tubes.

Members from both teams worked together on the model, which was accomplished through several iterations. Shiran Yuan from our team was in charge of the 3D model design and printing of the hardware prototype.

NWU Parts Library

NWU’s Parts Library is open for all the teams around China this year. We contributed BBa_K4494197 (part C0001D in the NWU library), the Doc Toxin for Suicidal Modules for the future iGEMers.

Animation of Team Logo

We were short on arts and we wanted to add some kinesthetic elements to our wiki, the NWU-CHINA-A team helped us design the animation based on the graphic design of our team logo.

Education and Communication

Meanwhile, the two teams also hosted and participated in academic educational activities together.

We invited NWU-CHINA-A to co-organize a science popularization activity on synthetic biology for Beijing No. 22 Middle School.

We also participated in the Gut Alliance which was led by NWU-CHINA-A and other teams. We were responsible for the writing of the article "Gut Flora and Heavy Metal Poisoning".