Biosensor y método para fabricar un biosensor

A biosensor and a method for manufacturing the biosensor. The biosensor comprises an insulative substrate (1), an electrode system (2, 3, and 4), a reagent, and an insulating layer (5). The insulating layer (5) covers a part of the electrode system (2, 3, and 4). Also, a closed region (6) without the insulation layer is formed at where the reagent is. The closed region (6) is provided with an enclosing border having no sharp corner. The reagent covers the closed region (6) and does not go beyond the enclosing border. The biosensor also comprises an assisted diffusion electrode (12). The use of the enclosing border having no sharp corner and of the assisted diffusion electrode (12) reduces the edge effect of the reagent, allows the reagent to diffuse uniformly at response areas of the electrodes, effectively controls the amount of reagent used, reduces product costs, and allows for simple manufacturing.