Research On Key Technologies Of Detection System Of Integrated Nucleic Acid Detection Equipment

With the development of life science and technology,people’s attention to biomolecules is increasing day by day,and the development of rapid and accurate detection methods is of great significance to biomolecules.The discovery of PCR technology(Polymerase Chmn Reaction)has made a qualitative leap in in vitro molecular diagnostic technology.With the development of microfluidic technology,the direction of modern molecular diagnostics has become more and more miniaturized and integrated.Therefore,this article is designed An integrated nucleic acid detection equipment integrating nucleic acid purification,amplification and detection based on a microfluidic chip.This equipment can complete the pre-processing of PCR and the PCR process on the same equipment,which greatly reduces the cost of detection,And the whole process also avoids cross-contamination.The thesis first introduced the PCR technology and the widely used real-time fluorescent quantitative PCR instrument,analyzed its working principle and the status quo at home and abroad,and then introduced the principle of fluorescence analysis of the fluorescence detection system part;for the design core of this equipment—— The working principle of the microfluidic chip is also introduced in detail,the realization process of each part of its function is explained,and the structural design of the integrated nucleic acid detection equipment is briefly introduced.For the part of the fluorescence detection device,two detection schemes are designed.One is a confocal two-channel fluorescence detection scheme.This scheme can detect two wavelengths of fluorescence signals at the same time,and simulate the light path accordingly.The principle of imaging optics simulates the collimation and focusing process of light.The simulation results are used as the basis for selecting optical components.Finally,the experimental verification shows that this scheme is feasible;the other scheme is to use optical fiber as the transmission light path,this scheme Multiple channels of fluorescence signal detection can be performed at the same time,and the shortcomings of the complex optical path structure of the confocal dual-channel fluorescence detection scheme are avoided.However,fiber coupling is the difficulty of this scheme.Simulation has improved the accuracy of LED light source and fiber coupling.In the process of straightening and focusing,the divergence angle after collimation is within 5°,and the RMS radius of the spot after focusing can meet the requirements of the optical fiber.In the confocal two-channel fluorescence detection scheme,a stepper motor is needed to drive the fluorescence detection device to move.The PID controller of the stepper motor is optimized and simulated.The ordinary PID controller and fuzzy control theory,fuzzy neural network theory,particle The group optimization algorithm is combined for simulation,and the results show that its control effect is better without subjective factors.The built-up integrated nucleic acid detection equipment was tested and verified,and the confocal dual-channel fluorescence detection device was tested for repeatability and linearity.The results showed that the detection device can meet the detection requirements and carried out biological tests.The results confirmed that this equipment can meet the requirements of use.According to the test results,the detection method using the sensor has a complex optical path structure,combined with the recent rapid development of image processing technology,provides a new technical route for the fluorescence intensity value extraction in this device.First,the detection system platform is built to obtain the image,and then used OpenCV performs image processing on it to obtain the average gray value of the target area.This solution has a certain development space in the future market.Based on the microfluidic chip as the core,the entire equipment integrates the magnetic bead control platform,the microfluidic chip temperature control platform,the microfluidic chip motion platform and the fluorescence detection device into the same platform,which can be integrated The completion of the nucleic acid purification,amplification and detection process has greatly improved the integration and miniaturization of nucleic acid detection instruments.