Research On Key Technology Of Protein Detector Based On Microfluidic Chips

Protein plays an important role in the life activities, and is closely related with human health. Detection and isolation of proteins are the main technologies of protein research. In clinical protein assays, immunoassays have been widely used due to its high specificity and sensitivity. However, regular immunoassay has the weakness of large reagent consumption, long reaction time and requires a complicated process of samples and reagents.Recently, microfluidic chip system has attracted a lot because of its low reagent consumption, fast response and high sensitivity, and has been widely applied to various fields, such as biomedical analysis, environment monitoring, food safety and so on. Compared with traditional immunoassay method, immunoassay based on microfluidic chips has a better prospect in clinical and biomedical research, because it has an advantage in real-time online testing.So, based on the sufficient investigation of the development of protein detection devices based on microfluidic chips both at home and abroad, we determined to develop a modularized, highly-integrated, full-automated and high sensitivity system. The main contents are as follows:1. Research situation and development trends of protein detection technology based on microfluidic immunoassay chips were reviewed. Especially, detection methods, analytical methods and practical application were focused on.2. Fabricating process of microfluidic immunoassay microfluidic was introduced, including fluid-driven approach, the structure and material of the microfluidic chip.3. Optical equipment of the system was built. We used a blue LED with 470 nm wavelength as the exiting light source, and used a photomultiplier(PMT) as the photoelectric detector. Combined with the microscope objective, the dichroic mirrors, filters and coupling lenses, we completed a LED-induced confocal fluorescence detection system.4. Design of hardware was presented. It was based on ultra-low-power consumption MSP430 microcontroller core proposed by Texas Instruments, combined with automatic sampling unit, temperature control unit, scanning platform control unit. In addition, an amplified filter circuit was presented to acquire and process the fluorescence signal.5. After the entire system was integrated, experiments were carried out to get assessment of it. The device can control the reaction temperature at 37℃ with deviation less than 0.3 ℃. And the LED luminous power ranged from 3.75mW-3.85 mW, the resolution of the image achieved 49μm. The device can acquire fluorescence image at a concentration of 10-8mol/L FITC solution, and have a good linearity between 10-8mol/L to 10-7mol/L. Finally, a preliminary experiment was conducted that interleukin-6(IL-6) antibody was used to react with goat-anti-mouse secondary antibody. The experimental results revealed that the protein detection system was feasible.