Development And Application Of Immunoassay And Protein-protein Interaction Detection Platforms Based On Digital Microfluidic Chips

Digital microfluidic chip(DMF)represents a technology that inherits the traditional microfluidic technology advantages such as good airtightness,low reagent consumption,short analysis time,and small equipment size,and strips out complex structures such as pumps and valves.It has simple internal structure,high degree of automation and strong scalability,which indicating great application potential in the fields of medical diagnosis,chemical analysis,and life sciences.Based on the above problems,this paper takes micro-nano processing technology as the main method to design and process multiple DMF chips for different purposes,and successfully apply them to disease diagnosis and life science research.The main contents are as follows:(1)To overcome the problem of cracking and shedding of the dielectric film on the chip due to excessive residual stress after annealing,we measured the residual stress of the film by grazing incidence XRD method,and optimized the process parameters by orthogonal test method.A low-stress and high-quality film was obtained under the conditions of oxygen,a temperature of 450℃ and a time of 30 min.(2)To grapple with the problem that the external heating module of digital microfluidic equipment is too large and not convenient for operation,we designed and processed a digital microfluidic chip with integrated heat(DMF-Heat),and developed a"backside method" process that greatly reduced the process cost of DMF-Heat.Also,two types of supporting temperature control systems were also designed to achieve a temperature control of±1.5℃.(3)To deal with the cumbersome operation steps of acute myocardial infarction(AMI)markers in traditional immunoassays and the demand for professionals,time-consuming,and large reagent consumption,we established an automated,highly sensitive detection biomarker detection platform based on DMF,successfully realizing the combined detection of three markers.The high uniformity of the heating zone of the chip was materialized by the simulation of the DMF-Heat chip,and the incubation time was successfully shortened to 2 minutes.With only 30 minutes,the platform can simultaneously detect the concentration of three biomarkers in a blood sample,which is far shorter than the traditional kit method.(4)To handle the harsh environmental requirements,low automation,high cost and the need for professionals in the detection of protein-protein interactions,we developed a set of portable,low-cost and efficient protein-protein interactions detection equipment(DMF-PPI-Box)based on DMF.By providing a stable environment below 4℃ by integrating the semiconductor refrigeration chip,the interaction between the RILP protein and the Rab26 protein,which are closely related to insulin secretion,was successfully confirmed.