Glucose oxidase molecular layers immobilized on planar and porous SiO 2 substrates were characterized with techniques commonly used in microelectronics technology. Both planar and porous SiO 2 were used as inorganic platforms for the enzyme bonding. The immobilization protocol on planar SiO 2 was characterized using contact angle, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), while energy dispersive X-ray analysis (EDX) coupled with scanning electron microscopy (SEM) were used on porous SiO 2 samples. A conclusive confirmation of the enzyme presence in the SiO 2 matrix was obtained by gold nano particles labeling. This last measurement technique could be implemented to determine the enzyme concentration in the porous SiO 2 layer.