I Temperature control module

 Temperature control module provide constant temperature environment in the chip for two reasons:1.E.coil need constant temperature environment when they restore activity from freeze-dried state;2.E. coli have the best growth and metabolism state in constant temperature environment.

1.1 Design:

  Temperature control module consists of four parts, namely: alumina ceramic, heating piece, temperature sensor module and it’s supporting control module.The alumina ceramic is the base of the chip, and the chip is connected to it. The rest of the temperature control board is located on the instrument, and the chip is placed on it when used.The alumina ceramic allow the chips to heat evenly.The control module control the work of the heater piece.The temperature sensor provide temperature information of microfluidic chip to the microcontroller at real-time.

1.2 Material:

  Alumina ceramic piece’s thermal conductivity is 23W/(m^2*K), and the size is 45 * 30 mm. Heating piece’s rated voltage is 5V, the power is 10W, and the size is 40 x 40mm. Temperature sensor’s accuracy is 0.1 ° C.

1.3Working Process:

  Its working process is very simple:When the chip temperature is higher than 37 degrees, the control module control the heating piece to stop heating;when the temperature is higher than 37 degrees, the heating piece works again.

Demonstrate

1.Optical part

Introduction

On the one hand, our chip is the carrier of biological reactions, on the other hand, the chip is also our optical detection platform.The object we are going to detect is GFP and RFP.
The detection principle is using a certain wavelength of light through the chip to stimulate the GFP and RFP in the chamber and detecting the light intensity emitted by GFP and RFP.In this way,we can characterize the amount of fluorescent protein produced by engineering bacteria.Thus the relationship between the reaction of engineering bacteria and the light intensity was established.
So the upper part of the chip will not only through the instrument from the excitation light, but also through the emission light from the engineering bacteria. If the chip has a poor transmittance, both the excitation light and light will be seriously attenuated.Thus it will affect the detection accuracy.

Experiments

We used NOA81 as the material of our chip. In order to characterize the light transmittance of this material, we used fluorescent microglobulin as the source of fluorescence and observed the fluorescence by fluorescence microscopy to characterize the chip transmittance.

1.1.verify high clarity of our chip

1.1.1 Method

Inject 50uL Fluorescent microsphere solution into the chip and detect the optical distribution of fluorescence in the chip. Drip the fluorescent microsphere solution of the same concentration onto the glass slide and detect the optical distribution of fluorescence in the chip. Cover the glass coverslip and detect the optical distribution of fluorescence in the chip.

1.1.2 Experimental results

From A in figure,not only the fluorescence can we detect clearly,but also we can get the position of bubble easily,just like B,only dripping the solution on the glass slide.Compared with C,the blurred detection,We can get that it is high clarity that our chip has the properties of.That’s what we need,high clarify is good for our detection.

1.2.verify high light transmission

1.2.1 Method

a.0.1mol/L fluorescein sodium solution were diluted 7000 times, 10000 times,20000 times,getting solution ①,② and ③. b.Check their fluorescent values c.Inject ①,②,③ into the chip and detect the optical distribution of f

1.2.2 Experimental results

From A in figure,not only the fluorescence can we detect clearly,but also we can get the position of bubble easily,just like B,only dripping the solution on the glass slide.Compared with C,the blurred detection,We can get that it is high clarity that our chip has the properties of.That’s what we need,high clarify is good for our detection.

1.2.3Discussion

According to result figure ,we can find that the chip has very good transparency for the fluorescence.We find that even for 3000 of the fluorescence, a clear capture is also possible.
Futher quantitative analysis by histogram:
Comparing A and B,we found that more diluted 3000 times,the standard deviation is reduced by 2.91
Compared with B and C, we found that more diluted 10000 times the standard deviation is reduced by 10.It proves that the material has little to do with its attenuation by it’s linear decay.These have proved that the transparency of our chip is very good.

2.Temperature control module

Introduction

The purpose of this experiment is to verify that the temperature control module can control the microfluidic chip expression chamber temperature constant at 37 ° C . Because we hope that engineering bacteria can work efficiently, we need to build a temperature control module to provide an optimum growth temperature for E. coli. The fluorescent protein used in the project was expressed by Escherichia coli, and we knew that the optimal growth temperature for E. coli was 37 ° C.

Method

We injected the microfluidic chip into the LB medium and placed it on a temperature control platform for heating. The temperature of the surface of the microfluidic chip was measured by infrared thermometer, and the curve of the surface temperature of the microfluidic chip was plotted over time.

Results

The results show that the temperature module can control the temperature of the microfluidic chip chamber in the range of the optimum growth temperature of E. coli - 37 ° C (± 1 ° C).

3.Peristaltic pump injection testing:

Introduction

we want to verify that we use the peristaltic pump to complete the extraction of air inside the chip,driving the flow of liquid within the chip function

Method

First, we take the microfluidic chip, remove the red solution with a pipette, and then put the pipette tip on the microfluidic chip connector. Then we will make the peristaltic pump connector connected to the microfluidic chip hose,under the negative pressure of the peristaltic pump, the liquid in the pipette tip is injected into the chip.

Results

With the negative pressure of peristaltic pump, the liquid within the chip can be carried out smoothly.