Mullite (2SiO(2).3Al(2)O(3)) nanoribbons, millimetres in length and with a high width-to-thickness ratio, were synthesized at temperatures as low as 1150 degrees C. This high ratio made it easy to fabricate a single nanoribbon sensor. The I-V relation of the sensor versus concentration of glucose was recorded with a pico-ammeter. The sensor shows good reproducibility and long-term stability. This single nanoribbon sensor may be used as an in situ monitor. The nanoribbons were also characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and x-ray photoemission spectroscopy.