Microfluidic Heterogeneous Immunoassay Systems Based On Slotted Vial Array

Immunoassay is a well-established analysis technique with high specificity and sensitivity based on specific interaction between antigen and antibody,and has been widely used in clinical diagnosis,biochemical analysis,environment monitoring and food safety control.Heterogeneous immunoassay,especially enzyme-linked immunosorbent assay(ELISA),is the most important and widely-used quantitative method in the field of clinical medicine.However,in most of the traditional immunoassays,the operations are usually carried out manually,which are tedious and time-consuming,and the consumption for sample and reagent is among several hundreds of microliters.Microfluidics is the science and technology that manipulate small(nL-pL scale) amount of fluids inμm-scale channels and microfluidic systems.Microfluidic analytical systems have the advantages of fast analysis,low sample/reagent consumption and potential for integration and automation.The combination of microfluidic technique with immunoassay provides significant improvements in analysis speed and throughput,sample/reagent consumption,and integration and automation of the system.In chapter 1,the progress in microfluidic immunoassay systems,especially in automated heterogeneous immunoassay,is reviewed.In chapter 2,an automated microfluidic immunoassay system was developed based on capillary and slotted-vial arrays,in which fully automated operation for multi-step immunoassay was achieved.The system was applied in the immunoassay of human IgG.The assay for nine human IgG samples was achieved within 10 min. The limit of detection for IgG was 1.0μg/mL.The precision of the system was 1.8% (RSD,n=9).The sample and reagent consumption was 1.1μL for each cycle.In chapter 3,a microfluidic immunoassay system was developed based on slotted-vial array,microperistaltic pump and PDMS chip.The peristaltic pump with a micro-gear was used for liquid driving in six microchannels in PDMS chip,which had advantages of simple structure,ease of building,good reliability and adjustable flow rate range from 0.21μL/min to 4.4μL/min.The feasibility of the system was demonstrated in a preliminary immunoassay for human IgG.The assay for five IgG samples was achieved within 8 min.The sample/reagent consumption was only 0.4μL,and the limit of detection was 1.0μg/mL IgG.