In this project, we have successfully constructed a biosensor by using J33201 part, which is sensitive to arsenic with a detection range of 50ppb-10pp
However, considering that the minimum detection limit of As in WHO in drinking water is 10ppb, and the detection limit of biosensor we constructed is 50-100ppb, we intend to build a more sensitive biosensor to increase our minimum detection limit to 10ppb.
In addition, since the concentration of arsenic in the groundwater in nature may be more than 10ppm, we intend to build a higher threshold biosensor, so as to improve our detection threshold.
According to the strength of RBS, we selected RBS with different strengths, including B0034 (the strongest), B0032 (medium strength), and B0031(weak).
Our design is as follows
The corresponding plasmids were transformed into E. coli DH5 alpha and the whole-cell bacteria biosensors were constructed.Test the threshold of reaction of different concentrations of arsenic to these biosensor.We can model the threshold of these reactions.
Through the literature, we have found an new approach called traffic light method that can detect heavy metal ions qualitatively and semi-quantitatively by a internal calibration by using multiple biosensors with distinct reporter protein outputs at a given analyte concentration.
It is possible to define arsenite concentration ranges using combinations of these cell lines, which show consistent trends over time within a given concentration. The principle of traffic light method are shown as follows
Our method is simple to operate and suitable for layman operation applications because it eliminates time-consuming and technically demanding calibration. We hope our biosensors can be used for field detection in the future, including groundwater in arsenite-comtaminated areas, remote mining areas.