Latest revision as of 20:02, 17 October 2018

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Description & Design

This part is an improvement of part BBa_K2088015, which consisted by the same copper ion detecting promoter and GFP as reporter. Comparing with BBa_K2088015, our improvement is using RFP to replace GFP as reporter. The composition of part BBa_K2826008 is shown in Figure 1.

Figure 1: Composition of part BBa_K2826008

Experimental method

2.5 ml of LB solution was added with 2.5 ml of sterilized ultrapure water, and BBa_K2826013 broth was added to make a final concentration of 0.02 OD, cultured at 37 °C on a shaker for 10 hours. 100 μL of bacterial solution was sampled every 2 hours to detect red fluorescence intensity. When measuring wastewater, replace 2.5 ml of ultrapure water with 2.5 ml of waste water.

Results and Discussion

As shown in Figure 2, with the extension of culture time, the fluorescence intensity of eRFP gradually increased which indicates that the expression level of eRFP in the medium gradually increased. In other words, the copper detection function of this working system was working normally. The concentration of copper ions in the waste water is close to 3ml/L. The detection results are similar to measurement result of ICP. Besides, as shown in Figure 3, as the copper concentration increased, the color turned redder. It is proved that the copper detection function of this working system was working as we expected.

Figure 2: Curve of fluorescence intensity and culture time under different copper concentrations

Figure 3: E.coli DH5α after culturing for 10 hours under different copper concentrations.

Conclusion

This design modification is based on three reasons and has significant advantage:

1. Comparing with GFP, RFP has a visible color which can be observed by naked eyes without UV excitation, therefore, in same condition, our new part can be used for qualitatively easily. Moreover, since it is not necessary to have a UV light source for qualitatively detecting, the prototype device could be smaller and cheaper.

2. RFP fluoresces red-orange when excited, therefore, in case of quantitative use, it will be same as GFP.

3. Usually, red color means “dangerous” and green color means “safe”. In the case of heavy metal pollution detection, the detecting result means more “dangerous” and “alert”, thus, using red color instead of green is in keeping with common sense.