SiO_2介孔薄膜修饰的红外表面等离子体共振传感器在波长测量模式下的特性研究

Study of Mesoporous-SiO_2-Film-Modified Surface Plasmon Resonance Sensors with Wavelength Interrogation in Near Infrared Region

分别利用射频溅射法和溶胶-凝胶模板法,在玻璃基板上制备45nm厚的金膜和45nm厚的SiO2介孔薄膜,用作表面等离子体共振(SPR)芯片,然后基于Kretschmann结构和共振波长测量模式构建了近红外SPR传感器。实验表明,在宽带平行光入射条件下,随着入射角度(θ)的减小,共振波长(λR)红移,折射率灵敏度(S=&λR/n)迅速提高。在θ=8°时测得的折射率灵敏度为24241nm/RIU,是θ=15°所对应的灵敏度(2524.2nm/RIU)的9.6倍。与常规的裸金SPR传感器相比,在相同的共振波长下,SiO2介孔薄膜修饰层使得SPR共振吸收峰明显变窄,光谱分辨率升高。低浓度溶菌酶水溶液在θ=10°时测得的SPR近红外共振波长随溶菌酶浓度增大而线性红移,其斜率为&λR/C=1.5×107 nm.L/mol,即溶菌酶浓度增加6.67×10#8mol/L能够导致共振波长红移1nm。1×10#7 mol/L Cu2+溶液可使SPR共振波长红移3nm。

An infrared surface plasmon resonance（SPR） sensor with wavelength interrogation was prepared based on Kretschmann configuration.The SPR chips were fabricated by sputtering a 45-nm gold layer on the glass substrate followed by sol-gel template synthesis of a 45-nm-thick mesoporous silica film.The experimental results indicate that with a broadband collimated incident beam both the resonance wavelength（R） and the refractive-index sensitivity（S） increase with decreasing the incident .The refractive-index sensitivity was measured as S=24241 nm/RIU at ,being 9.6 times as high as S=2524.2 nm/RIU obtained at.Compared with a conventional SPR sensor with a naked gold film,the modification of SPR chips with mesoporous silica thin films makes the resonance absorption band narrower and consequently offers a higher SPR spectrum resolution.The results measured at using low concentrations of aqueous lysozyme solutions indicate a linear dependence of the resonance wavelength on the protein concentration with a slope of implying that an increase of 6.67＊10-8 mol/L in protein concentration can causes a redshift of;For the detection of Cu2＋ ions,the results indicated that adsorption of Cu2＋ions from the ;-7 mol/L aqueous solution can make the resonance wavelength redshift 3 nm.