Microfluidic Immunoassay System Toward In-situ Analysis

Immunoassay is one of the most important methods of protein detection and is a key part of disease diagnosis. So far, most of the medical detections require large instruments and professional operations in laboratories, and the analysis time ranges from hours to days. However, the emergent diseases such as acute myocardial infarction and communicable diseases require detecting the real sample at or near the patient quickly. So, it is urgent to find a rapid, reliable and cheap system without any professional action for the point of care testing (POCT). Microfluidic analysis systems, due to their low sample consumption, integration, and high sensitivity, provide many possible methods for site analysis.In chapter1, the development of microfluidic immunoassay systems, especially the driving part in these systems in the recent years is reviewed.In chapter2, a low-cost and automatic liquid operation system based on a mini peristaltic pump for solid-phase immunoassay in point of care testing was developed. The labor-intensive process of immunoassay, including sample metering, sample introduction, rinsing and sandwich immune reaction, was triggered by one action and accomplished automatically in12min. The system consisted of three parts, including a capillary immune column, a reagent-loaded cartridge and a mini peristaltic pump. The cartridge was made up of a Teflon tube which was filled with reagents. The novel mini peristaltic pump was programmed to control the flow direction, flow rate and running time to realize the complicated liquid-handling operation without the need of human intervention. Human IgG was measured to demonstrate the performance of the system, and a limit of detection of0.68μg/mL, a dynamic range of0-300μg/mL and a reproducibility of2.4%(RSD, n=5) were achieved. The size of the total system is about5cm×3cm x3cm.