Optimization of an inorganic/bio-organic matrix for the development of new glucose biosensor membranes

A new mixed membrane material for amperometric glucose biosensors, based on immobilization of glucose oxidase (GOD) in inorganic laponite gels followed by an enzyme crosslinking through glutaraldehyde (GA) is investigated. This method gives the possibility to modulate the enzyme loading in the biomembrane, the corresponding sensitivities obtained being directly proportional to the enzyme content in the membrane. Thus, with a GOD/laponite ratio of 3.3, sensitivities reach up to 132 mA M−1 cm−2 for a linear dymamic range from 10−2 to 20 mM. Effects of oxygen and temperature have been investigated. The analysis of the bioelectrode characteristics shows a good permeability of this inorganic/organic enzymatic membrane. A specific design, combining a Nafion membrane and incorporation of polyphenol oxydase, allows to reduce the effects of interfering species such as ascorbate, urate and acetaminophen by a factor 4.