The particular sensitivity of the surface plasmon resonance (SPR) to changes in the local environment of nanoparticles (NPs), allows their use as platforms to probe chemical and biochemical binding events on their surfaces without any labeling. We performed a comparative study of gold and silver NPs based biosensors, prepared within the same conditions, in order to determine which one seems the best for biological sensing. Our results attest the superiority of Ag NPs over Au ones. Indeed, Ag NPs exhibit a more intense SPR band than gold NPs. Moreover, the Ag SPR band is more sensitive to the environment modifications. These two properties allow the detection of a lower concentration of target species when functionalized Ag NPs are used instead of gold ones.

Reference: M. Lismont and L. Dreesen, Mat. Sci. Eng. C, in press (2012)