A sensor for measuring a concentration of an analyte in a solution. The sensor comprises a substrate layer, an electrode layer and an immobilized enzyme layer. The sensor further includes an enzyme/polymer layer and/or a hydrophobic layer. The enzyme/polymer layer includes an enzyme disposed within a polymer matrix. The hydrophobic layer is formed from a material that is more hydrophobic than the immobilized enzyme layer material. In certain embodiments, the sensor includes the enzyme/polymer layer and the hydrophobic layer disposed between the enzyme/polymer layer and the immobilized enzyme layer such that the enzyme/polymer layer is disposed along the hydrophobic layer within an area above the immobilized enzyme layer.