Fabrication of a novel hydrogen peroxide biosensor based on C@Au composite

A promising hydrogen peroxide (H2O2) biosensor was fabricated by the immobilization of hemoglobin (Hb) on C@Au composite surface. The composite with carbon spheres and gold shell (C@Au) was synthesized via the seed-growth assembly technique. The assembly of the gold shell on carbon sphere surfaces was characterized by scanning electron miscroscopy (SEM). Owing to the unique structure and large surface area of the gold shell, the composite offered an effective interface for the immobilization of hemoglobin to fabricate a H2O2 biosensor. The obtained biosensor showed a wide linear range from 5.0 microM to 135 microM with a detection limit of 1.67 microM at 3sigma, and the apparent Michaelis-Menten constant (Km(app)) of the immobilized Hb was calculated to be 88.6 microM. Moreover, the biosensor also exhibited good reproducibility and long-term stability. Therefore, this kind of composite can provide an ideal matrix for protein immobilization and biosensor fabrication.