Study of carbon nanotube modified biosensors for monitoring uric acid and total cholesterol in blood

The carbon nanotube modified biosensors for respectively monitoring uric acid (UA) and total cholesterol in blood were studied. The transducers were based on two screen-printed carbon electrodes, a carbon working electrode and a reference electrode. For UA sensors, uricase was immobilized on the surface of electrodes together with potassium ferrocyanide as electron transfer mediator. For cholesterol sensors, the corresponding enzyme system consists of cholesterol esterase, cholesterol oxidase, peroxidase and potassium ferrocyanide. Multi-wall carbon nanotubes (MWNTs) and single-wall carbon nanotubes (SWNTs) were applied to prompt electron transfer. Experimental results showed that the carbon nanotube modified biosensors offers a reliable calibration profile and stable electrochemical properties. The calibration graphs were linear up to 200mg/L UA and 400mg/dL cholesterol