The methods most commonly used for the construction of plantbased biosensors are the retention of a thin tissue slice on the surface of the electrode with a dialysis membrane, and the incorporation of the tissue into a carbon paste matrix. In the membrane-based biosensors, the membrane has to impede the leakage of the enzyme away from the electrode surface but has to allow the substrate diffusion into the plant tissue. As mentioned above, this diffusion resistance may be responsible for long response times. Carbon paste electrodes are able to reduce the response time to seconds.