表面等离子体共振(SPR)是近年来兴起的一种光学检测技术。 其主要利用光波经全反射后产生的倏逝场与金属相互作用而感知外界介质的折射率变化。 理论上任何介质折射率变化现象的发生都能被SPR技术检测到。 在实际应用中, SPR传感器存在灵敏度不高, 检测信号不强等缺点, 因此对提高SPR传感器检测灵敏度的研究一直备受关注。 氧化石墨烯又被看成是石墨烯的氧化物, 它有着与石墨烯相近似的光电学特性, 但又比石墨烯更容易进行化学修饰, 因此被广泛用作SPR传感芯片的表面镀层来提高灵敏度。 将氧化石墨烯用于修饰SPR芯片以提高灵敏度的报道很多, 但对氧化石墨烯的使用量说法不一, 并且在制备氧化石墨烯修饰传感芯片时需要浸泡很长一段时间, 大大影响了芯片制备效率。 该研究中使用长直链功能化聚乙二醇(polyethylene glycol, PEG)对SPR金芯片表面进行化学改性, 用流动冲刷的方法使氧化石墨烯溶液对芯片进行修饰。 通过对折射率变化响应信号的对比, 最终确定氧化石墨烯最佳使用浓度为0.5 mg·mL-1, 并且将修饰时间降到20 min以内。 研究了不同波长入射光对氧化石墨烯修饰后芯片共振峰的影响, 并对芯片整体性能进行了评估, 得到950 nm入射光波下芯片灵敏度为243.2°·RIU-1, 品质因数(FOM)值为82.2 RIU-1。 这一数值比在原始800 nm入射波长下的同芯片灵敏度提高了33.3%, FOM值提高了36.1%; 是800 nm波长下裸金芯片灵敏度的4倍, FOM值的3.41倍。 该研究所提出快速制备氧化石墨烯修饰SPR传感芯片有着成本低, 制作快等优点, 在生化检测领域有着广阔的应用前景。

Surface plasmon resonance (SPR) is an optical detection technology that has emerged in recent years. It mainly uses the evanescent field generated by the total reflection of the light wave to interact with the metal to perceive the refractive index change of the external medium. Theoretically, any phenomenon that causes a change in the refractive index can be detected using SPR. However, in practical applications, SPR sensors still have shortcomings, such as low sensitivity and weak detection signals, so the research on improving the detection sensitivity of SPR sensors has always attracted much attention. Graphene oxide, also regarded as the oxide of graphene, has optoelectronic properties similar to graphene and is easier to modify than graphene chemically, so it is widely used as the surface of SPR sensor chips coating to improve sensitivity. There are many reports of graphene oxide being used to modify SPR chips to improve sensitivity. However, there are different opinions on the use concentration of graphene oxide, and it needs to be immersed for a long time when preparing graphene oxide-modified sensor chips, which greatly affects the chip fabrication efficiency. In this study, long-chain functionalized PEG was used to modify the surface of the SPR gold chip chemically, and the graphene oxide solution was used to modify the chip by the method of flow scouring. By comparing the refractive index change response signals, it was finally determined that the optimal concentration of graphene oxide was 0.5 mg·mL-1, and the modification time was reduced to less than 20 min. The influence of incident light waves of different wavelengths on the resonance peak of the graphene oxide-modified chip was studied, and the chip’s overall performance was evaluated. The chip’s sensitivity under the incident light wave at 950 nm was 243.2°·RIU-1, and the FOM value was 82.2 RIU-1. This value is 33.3% higher in sensitivity and 36.1% higher in FOM than that of the same chip at the original 800 nm incident wavelength, and it is 4 times in sensitivity and 3.41 times in FOM that of the bare gold chip at 800 nm wavelength. The institute proposed that the rapid preparation of graphene oxide-modified SPR sensor chips has the advantages of low cost and fast fabrication and has broad application prospects in the field of biochemical detection.