Development Of SPR Micro-optical Fiber Spectrometer And Construction Of Signal Amplification System Of Sensing Interface

In the past decade,the development of surface plasmon resonance(SPR)technology has witnessed great progress in optical sensing.The characteristics of unmarked,on-site and real-time dynamic detection make SPR sensor technology have incomparable advantages over other optical detection technologies.At the same time,the measurement is heterogeneous,and the recognition unit is fixed at the interface with the flow of different binding units to monitor the concentration changes and binding dynamics in real time.SPR sensors can be divided into wavelength type,angle type and phase type.Among them,the wavelength modulated SPR sensor has a wide incident spectrum range,and the wavelength range can be adjusted under the premise of fixed angle.Therefore,it has more advantages than the other two in terms of physical volume,imaging and detection parameters.Wavelength modulated SPR sensors,also known as spectral SPR sensors,can use fiber optic spectrometers as detectors.The core of the fiber is made of glass or plastic,which increases the momentum of light and allows a range of incident angles to travel through the fiber.However,in recent years,the demand for miniaturized portable instruments is increasing.In order to realize the field detection in harsh environment or emergency environment,the research and development of miniaturized portable experimental equipment has been widely concerned.This paper focuses on the development of a small portable SPR analyzer core component-micro optical fiber spectrometer module,mainly from the optical path,structure,circuit,interface and software design five aspects.Using Czerny-Turner optical structure,a micro-optical fiber spectrometer module with two optical paths and three focal lengths was developed.The structure design adopts the optical cavity and the electrical cavity double cavity structure design.The circuit design uses ILX554 B linear CCD photoelectric sensor.The interface design includes optical interface and electrical interface.The optical interface is matched with the SMA905 standard interface,and the quartz fiber jumper is used as the optical input interface,which makes the use of the instrument more flexible and reduces the volume of the instrument.The electrical interface uses a plug and play small USB interface.Finally,the software is designed to realize the functions of spectral parameters,data processing,peak finding and output.Through optical matching,electronic matching,interface matching and software matching,the micro-optical fiber spectrometer module and small portable SPR analyzer are effectively matched.Nanohybrid materials have good biocompatibility,catalysis and adsorption,and can catalyse,conduct electrons and amplify response signals,so they play an important role in surface plasmon resonance sensing technology.The introduction of nanohybrid materials can produce electromagnetic coupling effect with the gold film of SPR sensor,thus amplifying the SPR response signal and significantly improving the detection sensitivity.In this paper,a self-developed small portable SPR analyzer and a miniature optical fiber spectrometer were used to construct the sensing interface based on PDA-ZnO@Au nanomaterials.The synthesized ZnO@Au nanocomposite particles not only have the dual characteristics of nanocomposite materials and traditional zinc oxide,but also have the characteristics of large specific surface area and high chemical activity.Moreover,the gold-coated nanocrystals improve the optical properties of ZnO,expand the loading capacity,and have better biocompatibility.The polydopamine(PDA)coating can react with the antibody with Schiff base to directly fix the antibody.At the same time,GNRs-SA-biotin-Ab2(GSAB-Ab2)was constructed with Streptavidin and biotin,one of the strong affinity systems,to obtain the secondary enhancement of SPR signal.The detection range of human immunoglobulin(h Ig G)is 0.0375-40 μg m L-1.The minimum detection concentration of h Ig G obtained is about 67 times lower than that of the traditional SPR sensor based on gold film,which proves that the developed micro-optical fiber spectrometer has good sensitivity and stability in the application of SPR sensing technology.Meanwhile,the detection signal is amplified by the introduction of nanomaterials,which further improves the sensitivity of the small portable SPR sensor combined with the micro-optical fiber spectrometer module.