光纤表面等离子体共振生物传感器检测植物激素脱落酸的研究

Detection of plant hormones abscisic acid by optical fiber surface plasmon resonance biosensor

设计了一种基于纳米颗粒的光纤表面等离子体共振传感器,该传感器由包裹金膜的光纤和金纳米颗粒组成,纳米耦联金膜后形成纳米量级的局域结构,位于纳米颗粒极化方向的电场强度明显增强,并对外界环境折射率的变化敏感。论文以塑料包层光纤为基底对传感器结构进行了验证,通过将去包层的光纤表面巯基化,游离态的金纳米粒子很容易自组装在光纤表面上,形成表面等离子共振传感器纳米涂层,粒径为10 nm的金颗粒在0~5 mmol·L-1浓度变化中,传感器光谱共振峰移动10 nm,传感器对折射率变化的平均灵敏度在2000 nm·RIU-1。将传感器用于植物激素脱落酸的浓度检测,试验结果表明,使用核酸适配体功能化的金纳米粒子后,低浓度的植物激素脱落酸分子可以特异性地结合核酸适配体,共振峰位置在0.1~1.6μmol·L-1的浓度变化中移动了3nm,分辨率为0.535μmol·nm-1。这种纳米颗粒光纤表面等离子共振传感方式具有制备方法简单和灵敏度高的特点,可以在其他生物小分子的微量检测中发挥作用。

A optical fiber surface plasmon resonance sensor based on the nanoparticles was proposed.The sensor consisted of optical fiber coated by gold film and coupled gold nanoparticles.After coupling gold layer with nanoparticles,a nanoscale local structure will be formed successfully.The electric field intensity in the polarization direction of the nanoparticles was significantly enhanced,and was sensitive to the change of the external environment refractive index.The sensor structure was verified by plastic cladding optical fiber as matrix in this paper.Through sulfhydrylation of the surface of the de-coated optical fiber,the free gold nanoparticles could be easily self-assembled on the surface of optical fiber to form the nano-coating of the surface plasmon resonance sensor.The resonance peak of this sensor was found to move by 10 nm when it was used to sense the Au nanoparticle concentrations from 0 to 5 mmol·L-1 with the particles size of 10 nm.And the average sensing sensitivity of this sensor to the change of refractive index was 2000 nm·RIU-1.Finally,this sensor was verified with the plant hormone abscisic acid concentration.Studies have shown that the low concentration of plant hormone abscisic acid molecules could specifically bind to the nucleic acid aptamer-functionalized gold nanoparticles.The resonance position was shifted by 3 nm in the concentration change from 0.1 to 1.6μmol·L-1.The resolution of detection was 0.535μmol·nm-1.This nano-coated fiber surface plasmon resonance sensing method had simple preparation and high sensitivity,which was expected to play a role in the trace detection of other small biological molecules.