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

1

00 times.The gold nanorods whose aspect ratio is 2

and longitudinal SPR is 630nm can achieve maximum enhancement of biosensor sensitivity

about 90

1

00 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.