金纳米棒对SPR生物传感器灵敏度的增强效应

Sensitivity enhancement effect of gold nanorods on SPR biosensor

研究不同长径比的金纳米棒对表面等离子体共振（SPR）生物传感器灵敏度的增强效应。利用晶种生长法合成不同长径比的金纳米棒,并对其形貌、光学性质进行表征。采用双抗体夹心法,以金纳米棒与羊抗人IgG的偶联体作为第二抗体,利用实验室自行研制的波长调制SPR生物传感器对人IgG进行测试。实验结果表明：不同长径比的金纳米棒可使人IgG（1 mg/L）与羊抗人IgG的反应信号增强20~100倍;长径比为2、纵向等离子体共振吸收峰为630 nm的金纳米棒的增强倍数最大,为90~100倍;利用此金纳米棒增强后,可将SPR传感器对人IgG的最低检出限由500μg/L减小到10μg/L,灵敏度提高50倍。金纳米棒能大幅度提高SPR生物传感器的灵敏度,且金纳米棒的纵向等离子体共振吸收峰越接近SPR分析仪的共振波长,增强效应越好。

The sensitivity enhancement effect of different aspect ratio on gold nanorods（GNR）surface plasmon resonance（SPR）biosensor is studied.GNR with different aspect ratio are synthesized using typical seed-mediated solution phase approach.Characterization of those geometric features and optics properties are performed.By using double antibody sandwich technique,as the second antibody the GNR-antibody,laboratory-designed wavelength modulation SPR biosensor is used to test human IgG.It is found that GNR with different aspect ratio can amplify the response for human IgG-sheep antihuman IgG 20~100 times.The gold nanorods whose aspect ratio is 2 and longitudinal SPR is 630nm can achieve maximum enhancement of biosensor sensitivity,about 90~100 times;using this gold nanorods,the detection sensitivity of the SPR biosensor is estimated to 10μg/L,which is 50 times more sensitive than the SPR biosensor without gold nanorods.GNR could significantly enhance the sensitivity of SPR biosensor,and maximum enhancement effect can be achieved when the longitudinal surface plasmon resonance peak wavelength of GNR functionally matches the surface plasmon wavelength.