Improving the sensitivity of biosensor by use of the Ag and SiO_2 films

摘要

For improving the sensitivity of a SPR biosensor, we proposed a new combination of the thin silver (Ag) and SiO_2 films, and used the common-path heterodyne interferometry. Although the Ag film has higher sensitivity than the gold (Au) film, but Ag has toxicity for many media and it is easy to be oxidized. In order to enhance the sensitivity and protect the tested medium not to directly contact with Ag, we selected a coating of SiO_2 on the Ag film for the reason of it is cheaper and easy to obtain. The simulations and experimental results are shown that its best resolution could reach to the value of 6.9x10~(-9)RIU.