---

This device includes two parts, one of them is physical instrument and the other is matched software.

Our device matched experimental detection is consists of fourteen parts, including bottom plat, guide rail, chip slot, motor cabinet, toothed belt, driving wheel, driven wheel, testing scaffold, LED support, control, light barrier, hemispheroid, miniature photoelectric switch, article shading, etc.

The graphical representation will clarify the principle of how this device works.

Step1: Bioluminescence, mostly depends on the reporter genes varies as gfp, rfp, yfp etc;

Step2:Collecting lights: in this part, we use a photo dyed(PD) to collect light intensity data then transform it into electricity (nA). Here we need a illuminant to motivate the chassis bacteria to produce bioluminescence in our comprehensive detection in E.coli; because our recombinant bioluminescent E.coli is transmitted into a plasmid with luxAB to produce blue-green light itself so there is no need to add an outer illuminant. On the contrary, as for another specific detection, an additional illuminant is necessary. It is worth noting that we use LED (385nm) as stimulant. Consequently, the following circuits will transform electricity into voltage for the range of 0-10V.

Step3：Operational amplifier. It is an OP-AMP precision and the model is OPA602AU.

Step4: Second-order active low-pass filter. It will complete signal processing .

Step5: Analog digital conversion(ADC),type is AD7707. Through this process, the analog signal will exist in a digital way.

Step6: Single Chip Microcomputer. Digital signal will come into play. It will be linked to a computer by serial ports.

Figure: The structure of matched chips which are used in our device.

Figure:The software we designed to match with our device .

The device has been tested using rhodamine B. Following figure is the sensitivity curve. The detection limit is lower than 1ng/ml.

Figure:Sensitivity curve