Study Of The Injection System For A SPR Biosensor Array Device

Surface plasmon resonance (SPR) biosensor is a new high-precision biochemicalanalysis instrument. It has many advantages such as real-time monitoring, quick andeasy detection. Laboratory develope2×2array detection of a4-channel SPR sensor.Inthe SPR sensor apparatus, the reactant is required to react with various target moleculesdistributed at different positions of the flow cell. In order to overcome the error inducedby the difference of the stay time of sample solution (reaction time between the analytesand the target molecules), it is required to reasonably design the introduction system ofsamples to let the solution flow rate through detection zone as consistent as possible.Thus, it is necessary to research and develop an appropriate injection system.The purpose of this study is to design and fabricate an injection system for SPRsensor detector based on the related research work in our laboratory. It is required toensure the trace of sample solution and stability of the flow rate, improve presentsituation of laboratory,which use manual injection or single syringe pump，and toachieve continuous and automatic sample, cleaning, regulation of the flow rate, andswitching of the sample and buffer solutions. Experimental experience may beguidances for the research and development of a multi-channel SPR detector device.In this paper, the main contents include:Theoretical analysis and numerical simulation for the flow cell of the SPR arraydetector device. When the requirements of the laboratory SPR sensor are met, differentboundary shapes and lengths of the transition section are designed. The stability of theflow field within the detection zone is analyzed. Meanwhile, the impact of adding somemicrostructure arrays in the shuttle-shaped flow cell on the uniformity of the flow fieldis studied.Constructing the injection system composed by the pre-treatment section andmicrofluidic system. It includes the design of the flow path for a single sample injectionprocess, purchasing microinjection pumps and micro-valves, as well as fabrication ofthe microchannel and flow cell. Based on the study of molding the microchannel andflow cell as well as bonding PDMS and PMMA, a PMMA-PDMS composited simplemicrofluidic system is fabricated by using PDMS as the main material.Control of the pre-processing part of the injection system. In the entire injectionprocess, the control of micro-injection pumps and different micro-valves is realized by using the host computer. Meanwhile, control platform is designed by using VC++software, and the control operation is faster and more convenient.Injection system is coupled with the existing laboratory SPR sensor system to forma complete SPR detector. Distilled water and ethanol solution with a concentrationgradient are detected. Analyzing data of SPR resonance angles, we find that theintroduction of microfluidic system has played some roles to improve the stability offlow rate. Resonance angle is of a linear relationship with the reflective index of anlytes.Coupled SPR apparatus has good stability.