- Human Practices
Nowadays, detection methods for glyphosate mostly rely on expensive and sophisticated instruments which need to be operated by professional. These methods are costly, time-consuming and lack of portability. So, they cannot be used for field analysis of fresh samples. Tea has been widely planted in the world, the existing detection methods obviously can not meet the growing demand for detection. Therefore, we designed a new portable detection device to combined with our engineered bacteria in order to solve the above problems.
Based on the principle of fluorescence quantification, our hardware can detect the content of glyphosate in liquid samples and then share the data to mobile terminals in real time. The equipment is simple to operate, fast and does not require a large number of samples, and its accuracy can meet the basic detection requirements.
The whole hardware consists of three parts: one is an incubator for resuspating the lyophilized engineered bacterial powder, the other is a reaction device for mixing bacterial liquid with sample liquid and testing it, and a data transmission device for synchronizing data to the mobile terminal.
The two engineered bacteria were resuscitated in the culture chambers for a certain period of time until their activity was sufficient to complete the following detection task. The two engineered bacteria are then mixed with the sample and sent to a reaction chamber where the concentration of glyphosate in the sample can be quantified by measuring the intensity of the fluorescence generated by the reaction.
You can watch the video below for further information about the harware.
The two kinds of engineered bacteria were mixed with the medium in different culture chambers. The culture chamber was fixed on a plane connected with an eccentric rod and an electric motor, which could constantly shake the culture chamber, thus accelerating the recovery speed of the engineered bacteria. At the same time, shaking the culture chamber on a horizontal surface can also avoid spilling out of bacteria and save space.
After resuscitation, the liquid was mixed with the sample through a needle tube in a certain proportion and then sent to the reaction chamber. The needle is fixed on a suspension that can rotate. The whole needle lifting and suspension rotation are controlled by two stepper motors respectively. At the same time, another stepper motor can control the movement of the piston on the needle pipe through a rotating band, so as to conduct quantitative sampling.The two strains were mixed with the sample directly in the needle tube, and then sent to the reaction chamber.
In order to eliminate the interference of the external environment (light, etc.), the detection chamber is a complete "dark room" container. We use light-emitting diodes (leds) that emit specific wavelengths (420nm) and detect the fluorescence intensity at 528nm, then quantified fluorescence intensity by converting it to a physical quantity (current/voltage) that can be easily measured.
The data transfer
In terms of data interaction, we will communicate with Arduino SCM through Bluetooth® module, and users can realize real-time monitoring of the whole detection device after downloading our APP and obtain the required detection data.
Matched with the detection hardware is our self-designed software. Users can download it on Android phones. Before using our detection hardware, the phone need being connected with hardware via Bluetooth®. In another world, our hardware supports Bluetooth® data transfer.
After opening the detection page, users can follow the steps provided on the screen preparing for detection, which means that the operation progress is easily-using to every group. You can see these 6 steps below. While the hardware is working, users can learn the time left on the screen. (See the instruction at the end of this page)
A report will be given when hardware finishes working, which users can save or share as they like. All the information is stored in the database which is on the cloud server in case of data loss.
You can watch the video below for further information about the software.
【Version in Engish】
Solution A: distilled water (bottle)
Solution B: LB Broth 5mL (bottle)
Solution C: NADPH (bottle, 2000μM)
Capsule A: GRHPR & GOX
Capsule B: iNap
Step 1: Take X grams of tea leaves and boil them with X mL water for X min. ( Boiled tea water)
Step 2: Open the cover of our hardware.
Step 3: Put Solution B and capsule A into container A.
Step 4: Put Solution B and capsule B into container B.
Step 5: Put boiled tea water into container C.
Step 6: Close the cover and turn on our hardware.
[Due to the safety issue, we didn’t plan to carry out the actual experiments about the sample of tea. The value was not determined.]