Active Multilayer Centrifugal Microfluidic Chip And Its Applications In Biomedical Treatment

Due to its own cost,portability and high throughput,Microfluidic technologies have been the focus of academic and commercial research for a long time.With the improvement of the medical level in recent years,the application of microfluidic technologies have become more and more extensive.Microfluidic technologies integrate biochemical detection and analysis process on a micron scale chip,which canautomatically complete the whole process of detection and analysis.At present,microfluidic technologies have been widely used in kinds of applications including nucleic acid extraction,polymerase chain reaction(PCR),enzyme linked immunosorbent(ELISA),detection of virus,water quality and so on.However,traditional microfluidic technologies are facing challenges because of its inherent shortcomings,especially complex liquid driving and difficult operation mode.To solve these problems,the centrifugal microfluidics technologies which are the important branch of microfluidics,provide a simple solution.Centrifugal microfluidic technologies utilize the centrifugal force generated by the rotation of the motor as the driving force of the liquid,and integrate the biochemical detection and analysis process on a chip like a disc.It has been applied widely in the academic and industrial fields because of its simple driving mode,low cost and high integration.However,the existing centrifugal force microfluidic platforms and chips only rely on the action of centrifugal force,which makes the liquid handling more complex and the chip structure level is severely limited,and it is difficult to integrate complex biomedical medical applications.In order to solve these problems,based on the existing centrifugal force microfluidic technology,the wireless power supply module and the wireless communication module are integrated on the centrifugal force microfluidic platform,the electricity is introduced into the platform,and an active centrifugal force microfluidic platform is rebuilt.In addition,an active multi-layer centrifugal microfluidic disc was designed based on a built-in active platform,and the microfluidic structure layer and the circuit board(PCB)were coupled together by means of a heating resistor to heat the paraffin valve.The purpose of wireless real-time control of liquids.Based on these technologies,this paper successfully integrated a complete DNA extraction process on the active centrifugal microfluidic chip and realized the process from "sample to answer".The active centrifugal microfluidic platform built in this paper includes motor,drive module,wireless communication module,wireless power supply module,master control layer on the rotating platform,and mobile phone terminal.It is not only an integrated electronic device on the rotating platform,but also a microfluidic disc.The integrated electronic device provides a simple and convenient solution,and the wireless real-time control of the electronic devices on the rotary platform is realized through the wireless communication chip and the single-chip microcomputer in the main control layer.The active multi-layer centrifugal microfluidics disc includes the microfluidic structure layer and the printed circuit board(PCB)layer.The two layers are coupled in the form of heat.In the PCB layer,the heating resistance is below the paraffin valve of the microfluidic structure layer.The switch of the paraffin valve is controlled by the switch control of the heating resistance,and the digital logic in the PCB layer is introduced into the flow logic of the liquid for the first time,what's more,the accurate and reliable real-time control is realized by this way.This design makes the valve unrestricted by the surface tension and speed characteristics,and reduces the design difficulty of the application.Besides,it can break through the limits of the hierarchy and satisfy the biological application scene which needs a large number of valves,and greatly expand the integration capability of the chip.The PCB layer can be further divided into the controlled PCB layer and the main control layer.The two layers are connected by the inserting needle,and the controlled PCB layer is combined with the microfluidic structure layer to form a replaceable one-time multilayer chip.In addition,based on these technologies,a variety of universal functional units are designed,including liquid selection structure and liquid sequential loading structure,which are more reliable,stable and simple than the existing methods.A complete process of DNA extraction are also integrated on the disc,and three groups of DNA extraction experiments have been carried out in this paper.The purity and quantity of the extracted DNA are compared and analyzed in detail.In the 3 groups of experiments,the ratio of A260/A280 is between 1.8 and 2,and the difference is not more than 3%.In the 3 groups,the number of DNA extracted by chip is higher than that in the traditional way,the maximum difference is 4.5%.It is proved that the method of using chip to extract DNA is very effective.In order to prove the activity of DNA,we have carried out a real-time quantitative PCR experiment.The experimental results showed that the DNA activity extracted by the chip was fully satisfied with the requirement of DNA amplification.The active multi-layer centrifugal microfluidic chip designed in this paper is fixed on the active centrifugal microfluidic platform by pins,and utilize the paraffin wax valve heated by the resistance to solve the problems of the existing chip structure design complexity,liquid handling difficulties and Paraffin valves.The digital logic is introduced into the control of liquid flow logic for the first time.It also provides the solution for the integration of the large-scale paraffin valve in the chip.In addition,complex biological applications have been integrated on the chip,which shows the huge application prospect of our chip in biological treatment application.