Utilizing the innate advantages of microfluidic chip technology and rich experience in the development of analytical instruments, Wenxi shares can design and develop analytical instruments and systems based on microfluidic chips according to customer requirements. Wenxi Group has established a complete instrument development team. Based on the previous experience in chip, power, temperature control, detection, algorithm, control and design, Wenxi Group can provide customers with complete analysis and testing equipment. Custom development services. The development expertise focuses on the fields of medical diagnosis, food safety and environmental monitoring. It can provide customers with services ranging from "prototyping-principle verification-prototyping-product development" to the provision of mass production services and related markets. Qualification management. The following takes customer customized development case as an example to briefly describe several customized products:
First, detection of protein denaturation based on microfluidic chip
The project was designed for a research institute and the customer asked for the following: protein denaturation (-4°C to 90°C and room temperature to 90°C) and X-ray detection were realized in a short time. In order to meet customer needs, the following solutions are provided:
1) In order to meet the demand for protein solution cooling, the cooling sheet and fan structure are used;
2) In order to achieve precise control of the temperature in the cooling area, the feedback control of the electrothermal coupling refrigeration plate is used to ensure that the temperature in the cooling area is constant;
3) In order to achieve the protein solution room temperature and -4 °C requirements, the use of two-position three-way solenoid valve, respectively, control protein solution does not pass through the refrigeration zone (room temperature), and through the refrigeration zone (-4 °C), through a solenoid valve, to achieve Two kinds of temperature control;
4) In order to achieve rapid temperature rise of the trace protein solution, a platinum resistor is integrated on the PMMA chip, and the resistor is used for heating. The platinum resistor is magnetron sputtering and photolithographic patterning method, and the line width is 5 μm;
5) In order to solve the problem of slow heat transfer of PMMA, design and process diamond micro-channels, increase contact area and reduce dead volume;
6) In order to solve the problem of insufficient light transmission of PMMA, the detection area is sealed with KAPTON film;
7) In order to monitor the fluid temperature in the critical area, a PT100 resistor is integrated on the PMMA chip to actually measure the fluid temperature;
8) In order to facilitate the experiment, related PMMA brackets are designed to facilitate detection.
Second, microfluidic chip-based cell co-cultivation apparatus
The project was designed for a school fund project in Guangdong. The client’s needs were to verify the interaction between the adherent cells (A) and the suspension cells (B). The requirement was that the A cells should always be in the culture tank and the B cells should flow into the A culture tank. Flow back to the B culture tank, requiring the control instrument programmable. In order to meet customer needs, the following solutions are provided:
1) Through the difference in the size of A and B cells, the filtration membrane and filter head structure are used to achieve the inflow and outflow of B cells, and A cells do not participate in the circulation;
2) The reflux system adopts a positive and negative pressure constant pressure pump independently developed by Wenxi Co., Ltd. The inflow and outflow of cells are achieved through positive and negative pressure. The constant pressure pump is driven by the pressure and the disturbance is small, without affecting cell growth;
3) By modifying the control system of the constant pressure pump, the entire reflow process can be programmed, the minimum conversion time is 0.01s, and the cell fluid flow can be controlled by adjusting the pressure to achieve the dual control of the cell fluid flow rate and cycle time;
4) Since the pressure of the constant pressure pump is relatively large, in order to control the flow of the micro-upgraded cell fluid, the microfluidic chip is designed to act as a flow resistance to reduce the volume of fluid;
5) Using a two-position three-way solenoid valve and a microfluidic chip in conjunction with the use of a chip to control the inflow and outflow of cell fluid;
6) Protect the chip and solenoid valve with the seal structure, and place the entire structure in the incubator to reduce the dead volume of cell fluid flowing in and out.
The overall system structure is shown above. This system fulfills the customer's experimental needs. The system can work continuously for two weeks, and the working time meets the customer's demand for cell growth research.
Third, based on microfluidic chip micro-alignment instrument
The project is designed for the alignment and sealing of the PDMS chip in the organ-on-chip domain of a certain university in Shanghai. The custom-developed PDMS chip micro-alignment instrument requires the alignment error to be less than 10 μm.
1) In order to realize the alignment of the microstructures on the PDMS chip, an alignment platform with an accuracy of 1 μm is selected so as to adjust the position of the PDMS chip;
2) In order to reduce the alignment error of two PDMS chips, the X-Y-θ three-axis alignment platform was chosen to avoid the misalignment error caused by the long pipeline.
3) Use dual camera alignment to further reduce the θ axis error;
4) A single camera is equipped with two sets of alignment platforms to achieve three-axis adjustment of the camera to meet the chip alignment in different size ranges and height ranges;
5) Using a lever structure to save time and effort;
6) comes with light source, easy to operate.
Through the common operation of the above-mentioned multiple key components, the alignment and sealing of the two-layer PDMS chip are realized, and the alignment error is about 5 μm.