A gold[at]silica core-shell nanoparticle-based surface-enhanced Raman scattering biosensor for label-free glucose detection

The gold nanostar[at]silica core-shell nanoparticles conjugated with glucose oxidase (GOx) enzyme molecules have been developed as the surface-enhanced Raman scattering (SERS) biosensor for label-free detection of glucose. The surface-immobilized GOx enzyme catalyzes the oxidation of glucose, producing hydrogen peroxide. Under laser excitation, the produced H2O2 molecules near the Au nanostar[at]silica nanoparticles generate a strong SERS signal, which is used to measure the glucose concentration. The SERS signal of nanostar[at]silica similar to GOx nanoparticle-based sensing assay shows the dynamic response to the glucose concentration range from 25 mu M to 25 mM in the aqueous solution with the limit of detection of 16 mu M. The sensing assay does not show any interference when glucose co-exists with both ascorbic acid and uric acid. The sensor can be applied to a saliva sample.