In order to utilize our engineered bacteria to degrade ciprofloxacin in expired drugs, we designed a expired drugs recycling and degrading device in combination with the third generation fluorescence detection module.

In order to make it better adapt to more application scenarios and easy to maintain, we adopt a fully modular design, which is mainly divided into two large modules: water tank module and function module. The function module can be further divided into four small modules: a frame module, a crushing module, a detection module, and a degradation module.

We also designed double safety sterilization system to ensure the safety of our equipment.
Fig. 1. Expired drugs recycling and degrading device named Drug Avenger

Device design

crushing module

We designed the crushing module with reference to the principle of the shredder. It is mainly composed of a cover, two crushing wheels, a water pump, a filter membrane and so on. Our Drug Avenger takes the degradation ability as the highest priority. The PH of the mobile phase in the whole device is the best working PH of the CrpP, which may result in low solubility of CIP in the drug. This in turn Reduce the efficiency of the device, and our crushing module buffers and solves this problem. After entering the crushing module, the pills or capsules are first crushed into powder by the crushing wheel, and then the pump continues to flush the powder with water to dissolve it. The undissolved powder will be left by the filter membrane until it is dissolved, and the dissolved CIP will flow in the next module.
Fig. 2. crushing module

Detection module

The detection module will act as a sensor for the entire Drug Avenger to control the operation of equipment such as pumps in the device. By placing the detection bacteria we produced in the detection module, we can detect the CIP from the crushing module, and release AHL to the degradation module to open the expression of CrpP. By detecting fluorescence, the detection module can judge whether CIP is contained in the water from the crushing module to control the pumps and other equipment running and stop. The whole function module is divided into three layers. In addition to loading the detection module, the second layer reserves a lot of space. In the future, according to the actual situation, the layer can also be equipped with a small water tank to hold the detection bacteria to provide more AHL.
Fig. 3. Detection module
Fig. 4. Detection module placement diagram

Degradation module

The degradation module is mainly composed of a water tank and a pipeline. The water tank is filled with LB to supply degrading bacteria in the pipeline. The pipeline is composed of a keel and a dialysis bag, and the inside of the pipeline is filled with degrading bacterias embedded by sodium alginate.The water containing CIP and AHL from the upper layer will pass through the pipeline, and AHL will induce the degrading bacteria to express CrpP to degrade CIP. Finally, the treated water in the pipeline will be transported to the lower layer of the water tank module by the pump which is under the frame module.
Fig. 5. Degradation module
In the frame module where place degradation module, two bright blue light tubes are installed to keep the degrading bacteria alive by using the suicide gene in them. Once the degrading bacteria in the pipeline leaves, they will suicide because they cannot receive blue light.
Fig.6. Blu-ray device

Water tank module

The water tank module is used to supply water to the function module and to dilute, process and discharge the treated water from the function module. The water tank module is divided into two layers. The upper layer is used to supply water to the function module, and the lower layer is provided with a dark room to make the degrading bacteria suicide and a UV-sterilized lamp can be installed for secondary sterilization to ensure the safety of the device.
Fig7. Water tank module
In order to achieve the goal of double sterilization system as much as possible to ensure the most effective biosafety, we designed two blue light tubes to ensure the smooth work of the engineering bacteria, and designed a black box to implement the first safety mechanism to prevent engineering E.coli leaks. In addition, we designed to install a UV-sterilized lamp to ensure that all harmful bacteria are killed, and no other super bacteria are produced.
Fig. 8. Safety measures
We managed to make the degradation module. We first used the sodium alginate to embed the degrading bacteria into small balls, then poured the small balls into the pipes made of dialysis bag , and then loaded the pipes into the water tank filled with PBS buffer (In the future we will add LB to the water tank).We use pumps driven by mobile power supply to run the device and display a fast-forward video.
Fig. 9. Degradation module
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