A Detection System For Bead Based Capillary Chip

Point-of-care testing(POCT)is an important sub-area of in vitro diagnostic industry.Compared with traditional process of in vitro diagnostic,POCT has higher efficiency.POCT equipment has the characteristics of small size,low cost,high integration,simple operation,less sample requirement and fast detection speed.Microfluidic technology and multiplex detection technology are indispensable in the development of POCT.Microfluidic technology reduces the consumption of samples and reagents,and promotes the automation of reaction.Multiplex detection technology realizes simultaneous detection of multi-components and contributes to high throughput detection.Therefore,the combination of the two technologies can achieve a multiplex detection method that meets the requirements of POCT.In this paper,a low-cost microfluidic chip is designed and fabricated based on photonic crystal coding and microfluidics,and a fluid reaction device is constructed,which can be used for multiplex detection of biomolecules.The details of the research is as follows:1.The capillary chip and fluid reaction device.A capillary chip based on photonic crystal beads(PCBs)is designed,and its structure principle,fabrication steps and imaging effect are studied.A multi-channel fluid reaction device is constructed according to the immunoassay principle.The device includes microfluidic devices such as syringe pumps,solenoid valves and integrated circuit board.A PC software is developed for parameter setting and operation of the device to realize fluid control.2.Application of fluid reaction device in protein detection.The chip and fluid reaction device are used for protein detection,and a series of optimization of fluid control parameters are carried out to ensure sufficient reaction and effective washing while reducing detection time and improving detection efficiency.In addition,the device is used to simultaneously detect two kinds of proteins in a chip,which verifies the feasibility of multiplex detection.3.The processing of chip image.An image processing method for capillary chip is developed.Firstly fluorescence image was denoised,enhanced,segmented and all regions of the PCBs were accurately extracted.Then the coding of PCBs was decoded by photonic crystal colors,which stands for the protein species.Finally the fluorescence intensity and coding of PCBs were obtained,then the detection results were obtained.The detection limits of AFP and CEA are 4.3 ng/mL and 38.1 ng/mL respectively,which further verifies the feasibility of the system for multiplex immunoassays.