The Construction Of The Setups Of Multifunctional Optical Tweezers Based On Microfluidic Chip And Their Applications

Cancer is a serious threat to human health,so it is of great significance to accurately detect and analyze low abundance of cancer markers for cancer diagnosis,treatment and metastasis mechanism research.By virtue of the favorable properties of low sample consumption and strong extension as well as easy integration,microfluidic chip has been successfully applied to many bio-detection fields.Compared with traditional flow cytometry(FCM),the strategy based on microfluidic chip can achieve the detection and analysis of various bio-molecules in a miniaturized and diversified way.Along with their developments,luminescent nanomaterials possessed of excellent performance(high luminescence brightness,good stability,adjustable wavelength,strong anti-photobleaching ability,single excitation to multi-emission),especially with QDs and UCNPs,have obvious advantages of resisting photobleaching and other weakness and can be used to avoid spectral overlapping of the traditional organic dyes,which are pretty conducive to the development of miniaturized and portable chip-FCM.In recent years,optical tweezers are widely used in multidisciplinary fields because of their precise handling,non-contact and non-injury characteristics.On the one hand,they can be used to stabilize the particles in the fluid by persistently optical trapping in the same focal position and avoiding signal fluctuations,and only the data from a small number of samples are required for obtaining accurate results,thus avoiding a large amount of data statistics and analysis.On the other hand,the target can be accurately trapped and deflected in the fluid according to the real-time response of the signal by the way of remote control and a sterile environment,which is conducive to the data analysis.Therefore,by combining the microfluidic chip with optical tweezers,this work established a novel multi-functional optical tweezers analysis-detection platform for biomedical detection of major disease biomarkers,so as to realize the miniaturization,integration and automation of analysis and detection.Based on the above background,this thesis focuses on the establishment of automatic detection and analysis method of optical tweezers combined with nanomaterials labeling in the fluid,the following research work is carried out:(1)The setup of multi-function optical tweezers was designed and constructed with both software and hardware being developed,and it was optimized by adjusting the parameters and exploring the capturing performance.According to different application requirements,different devices were designed.Firstly,a miniaturized 980 nm laser optical tweezers for particle trapping and detection was constructed.Secondly,a high power 1064 nm laser optical tweezers with fluorescence activation was further optimized and upgraded.Finally,the structure and experimental parameters of the apparatus in a microfluidic chip were determined,and the stable signal detection and the releasing of the trapped particles were realized,which laid a foundation for automatic detection of biological samples and sorting of tumor cells for the future work.(2)Based on the construction of the miniaturized multifunctional optical tweezers instrument in the previous work,we demonstrate here an exceptional microfluidic chip assisted platform by integrating near-infrared optical tweezers with upconversion luminescence encoding.By using the two-color upconversion nanoparticles as luminescence tags and microbeads as carrier,we fabricated complex microbeads referred to a UCNPs-mi RNAs-microbead sandwich construct by a one-step nucleic acid hybridization process,and then obtained uniform terrace peaks for the automatic and simultaneous quantitative determination of mi RNA-205 and mi RNA-21 sequences with detection limit of p M level on the basis of a special home-built flow bead platform.Furthermore,the technique was successfully applied for analyzing complex biological samples such as cell lysates and human tissue lysates,holding certain potential for disease diagnosis.(3)Based on the establishment of high power 1064 nm laser optical tweezers system with fluorescence activation,the sorting model of the optical tweezers combined with tumor cell labeled by fluorescence nanospheres was established in the microfluidic chip.In order to realize specific labeling of the surface markers of MCF-7 cells and Jurkat T cells in this model,two-color fluorescent nanospheres were modified with different antibodies to identify and mark different cells.When cells went through the detection area in the microfluidic chip one by one,the data acquisition and control system can automatically read signal and then send instruction to optical tweezers control module according to the threshold judgement to realize trapping and deflection of the target cell.In order to explain this process clearly,the COMSOL Multiphysic was used to model the process in a microfluidic chip.