▎ 摘　　要

The article describes a wavelength modulation surface plasmon resonance (SPR) biosensor for human IgG. The sensor is based on the use of silver nanocubes (SNCs) and carboxy-functionalized graphene oxide (cGO). The surface of the SNCs was modified with 3-mercaptopropinic acid by silver-thiol chemistry, and this protects the SNCs from oxidation. The cGO possesses abundant carboxy groups that allow high-density immobilization of anti-human IgG on the gold film of the SPR chip. Successful conjugation to the surface was demonstrated by X-ray photoelectron spectroscopy. The SPR biosensor responds to human IgG in the 0.075 to 40 mu g mL(-1) concentration range. The limit of quantification (LOQ) is smaller by factors of 32, 8 and 4 compared to (a) a conventional sensor, (b) a GO-based sensor, and (c) a cGO-based sensor. The detection scheme presented here offers a versatile and sensitive platform also for determination of other proteins if the corresponding receptors are available.