Investigation Of Miniaturized Optical Fiber Surface Plasmon Resonance Biological Sensor Systems

Surface plasmon resonance (SPR) sensors have been widely used in biosensing, drug screening, food safety and environmental monitoring, because of their distinct advantages, such as high sensitivity, label-free detection, without purification, highly repetitive, and real-time monitoring. Fiber optic sensor technology has been one of the most potential sensor technologies, due to its light-weight, small size, electromagnetic immunity, corrosion resistance, and good reusability, they has been widely employed in industrial, civil, medical science and aerospace fields. Optical fiber SPR sensor is developed by integrating optical fiber sensing technology and SPR detecting mechanism together, which can be used for high sensitivity, high reliability measurement and possible to realize system miniaturization, low cost and integration of SPR sensor. These sensors show broad prospects for development and tremendous potential for application, it has been given more and more research concerns in recent years.In this paper, we focus on the systematic and miniaturization of fiber optic SPR biosensor experimentally and theoretically. Based on surface plasmons and its resonance theory, we design and demonstrate two SPR sensing elements by theoretical analysis and simulation of prism and optical fiber SPR sensor models; we develope miniaturization SPR sensor system using general photoelectric device, realize the SPR sensor information collection and analysis by VC++6.0 and the Labview software platform, and verify the feasibility of the sensor system through biochemical tests; we develop SPR signal control program based on Android operating system and realize micro integrated optical fiber SPR sensor system by combining optical fiber and capillary SPR sensors with smart phone. Major research works are as follows:1. Based on the fundamental theory of surface plasmons (Surface plasmon polariton, SPP) and the principle of SPR stimulation, we study the operation mechanism of fiber optic SPR sensor. We introduce the background and characteristics of SPR sensing technology and described the status and progress of SPR sensing technology, then analyze the different kinds of optical fiber SPR sensors and theirs application in sensor technology, and expound the basic theory of the SPR sensor, develop the theory model of optical fiber SPR sensor. Furthermore, we also analyze the influence of different parameters on the sensor performance by using the theory model of optical fiber SPR sensor.2. To meet the development requirement of miniaturized optical SPR detection system, we design and development of the optical fiber and capillary SPR sensor. Based on the basic properties of SPR and surface plasmons excitation principle, we design fiber optic SPR sensor and capillary SPR sensor, analyze and compare the absorption spectral characteristics of the two sensors. We test the two kinds of temperature and the refractive index response of the sensor and realize the detection of specific binding of proteins through modifying the gold film with antibody of concanavalin A (Con A).3. Combining optical fiber and capillary SPR sensor with general optoelectronic components, we design and realize the miniaturization of optical fiber SPR sensor system. We realize the miniaturization SPR sensor system by using the general light-emitting diode as light sourceoptical, the complementary metal oxide semiconductor (CMOS) image sensor as the detector and the fiber optical and capillary SPR sensors as sensing elements. Using the intensity compensation by reference channel for light source, the refractive index of the sensor system sensitivity and resolution reach 400%/RIU (Refractive index unit) and 7.5 × 10-4 RIU. Combining the surface chemical modification technology, the sensor system realizes the detection of biological proteins. Expanding a single optical fiber SPR sensor to 9 channels optical fiber sensing array, we implement integration SPR sensor system which contains the reference channel, control channel and multiple test channels, and apply the SPR sensor system to detect the mixed samples of Con A and immunoglobulin G. In addition, we achieve the self-reference capillary SPR biological image sensing system to compensate external fluctuations in biological sensing by comparing light intensity in different region.4. According to the demand of point-of-care sensor applied to families and individuals, we design and implement the integrated SPR sensing system based on smart phone platform. We use the LED flash and camera of smart phone as light source and detector and developed a controling prosgram based on the Android operating system. SPR sensors are used as sensing elements and special packaging module is assembled with smart phone. The sensor system has sensitivity and resolution up to 1136%/RIU and 7.4×10-5RIU. In addition, the sensor system tests the bovine immunoglobulin andits theoretical limit of detection (LOD) is 47.4nM. By comparing the performances of the smartphone SPR biosensor and commercial SPR sensing instrument, the smartphone SPR biosensor has significantly advantages of portable, low cost and integration.Finally, we summarize the full work, analyze and summarize the future research. Combination of phase detection method, nano-materials and nanostructures, the sensitivity and resolution of the sensor is expected to be further improved, which make the sensor achieve a lower concentration, smaller biomolecules biochemical reaction process detection and monitoring.