Platinum Metals Rev., 1994, 38, (3), 108
Rhodium in Glucose and Lacate Sensors
Amperometric enzyme microelectrode array strips are used to monitor clinical, environmental and industrial conditions, in particular to detect physiological substances such as glucose and lactate in small volumes of blood. Disposable sensor strips are used by diabetic patients to monitor their blood sugar levels. These sensors are manufactured by microelectronic technology using screen printing or lithography, with the reactive enzymes being immobilised in the microdisk pores by gel entrapment, cross-linking or covalent binding.
Now, researchers at the New Mexico State University have fabricated amperometric enzyme strips in a one-step electrochemical immobilisation using rhodium codeposited with enzyme to fix the enzymes in the pores of the disks. Rhodium lowered the overvoltage, giving very high specificity towards glucose, and offered not only an efficient way to retain the enzyme in the micropores, but also produced strong and preferential electrocatalytic detection of the liberated hydrogen peroxide, (J. Wang and Q. Chen, Anal. Chem., 1994, 66, (7), 1007–1011).
Using rhodium particles to fix the enzyme has removed the need for the membrane barriers and offers highly selective, fast and sensitive monitoring for mass produced reliable diagnostic strips.