Template:NAU-CHINA/hardware
Introduction
Our aim is to detect the mycotoxin- Zearalenone, which produced by Fusarium graminearum. When it is infecting wheat. So like many iGEM project, we needed fluorescent microscopy to characterize our cells. When there is Zearalenone, engineered yeast will express fluorescent proteins. By only the current method of detection, sending specimen to the government is not enough. So we want to provide a cheaper, efficient, and user-friendly hardware to detect mycotoxins.
The instrument is divided into detecting module and degrading module. There are seven functional parts totally, including microfluidic chip, temperature control system, fluorescence detection and excitation system, host computer and slave computer, mechanical parts, functional semipermeable membrane and electric power system
The microfluidic chip
It provides a platform for the growth of engineered yeast and a space for reaction. Microfluidic chip deals with the behaviour, precise control and manipulation of fluids that are geometrically constrained to a small, typically submillimeter scale. A reaction just needs very little samples and reagents, and simultaneously analyzes hundreds of samples.
Peristaltic pump
Peristaltic pump It is a type of positive displacement pump used for pumping a variety of fluids.
Microscope
The microscope should be able to excite the cells using an excitation laser with an excitation wavelength of 485 nm, which matched perfectly with the excitation requirements of our yeast cells.
Photosensors(OPT101)
OPT101 are sensors that convert some of the light energy absorbed into electrical energy.
Temperature control system
Temperature control is a process in which change of temperature of a space is measured or otherwise detected, and the passage of heat energy into or out of the space is adjusted to achieve a desired average temperature..
The host computer and slave computer
In order to make it easier to promote our equipment, have more application audience and better Interactive interface, achieve automatic control of the equipment, easy to use, our slave computer controls valve switch and injection rate by pre-set program and achieves logic temperature control. At the same time, the slave computer will send electric signal to the host computer, process into visual information and reflect to the user.
Design
Detection module
Our detection module includes microfluidics, fluorescence detection and dexcitation system and necessary mechanical parts. The microfluidics used in the project is made of negative gel NOA81 whose chemical composition is triallyl isocyanurate. Negative gel NOA81 has great biocompatibility and chemical inertness, and the production process is relatively mature, so we choose it as the microfluidics material for our project. In this part, microfluidics needs to use the fluorescence generated by live yeast to control LED blue light in degrading part, so the chip part needs temperature control device. We use glass aluminum ceramic for microfluidics substrate aims to provide a constant temperature environment of 30 degrees celsius for engineering bacteria with the help of heating Refrigeration chip. We add the sample to be tested and engineering bacteria into the microfluidic "reaction chamber". When the toxin concentration reaches the threshold, the engineering bacterium express green fluorescent protein. In order to stimulate the generation of green biological fluorescence, we use laser to excite green wavelength and filter laser by dichroic and filter, then we get purely biological fluorescence. Biofluorescence is sensed by the photosensitive element, issuing electrical signals. Microcontroller processes electrical signals and controls the intensity of the LED blue light.
Degradation Module
Our degradation module includes functional semipermeable membrane, LED blue light control part---OPT101. The peristal pump used in the project is designed to drive a set of rollers to rotate. Rollers roll through the soft tube, compressing and releasing repeatedly. Extrusion produces vacuum, inhaling fluid into the soft tube, then pumping process is completed. The device pumps in E.coli and treated samples induced by blue light, the bacteria that pass through the semipermeable membrane can be fixed on the semipermeable membrane and begin to work. After the upstream sensing module playing the role, E.coli secret toxin degrading enzymes induced by blue light. The toxicity of sample is reduced through the functional semipermeable membrane, so the membrane is a kind of “canister”.
There is always room for further improvements
Make it a Do-It-Yourself and inexpensive device in any lab. Each component in our setup is easily interchangeable to customize the excitation、 detection 、degradation capabilities for any project. Our optical setup did not only look impressive, but it was also crucial for characterizing the ability of our fluorescent cells to become a biosensor to detect the toxins and a converter to start over degrading module.
We want to empower people to pay more attention on the problem of the wheat products.
