| Research Abstract |
The sol-gel method has been demostrated as a low-temperature technique for the production of new inorganic materials. In this work, sol-gel silicate-based biosensors were made by utilizing a composite membrane of sol-gel enzyme film and electrochemically generated poly(1 , 2-diaminobenzene) film to improve the selectivity of the sol-gel enzyme sensors. However, the prepared sensor was poor in operational stability, because of the release of enzyme entrapped into the sol-gel matrics. Therefore, to prevent the leaching of entrapped enzyme, the prepared sol-gel enzyme sensor was exposed to glutaraldehyde vapor. This treatment was effective to improve the stability of the sensor, but tended to decrease the sensitivity because of enzymic inactivation. To improve these problems of sol-gel silicate based biosensor, the biotin-avidin affinity reaction was adopted for the production of the enzyme receptor composed of sol-gel matrics. Avidin, having four biotin binding sites, crosslinked and immobilized enzyme labeled with multiple biotin into the sol-gel silicate lattice, when tetramethyl orthosilicate solutions of biotin labeled enzyme and avidin were mixed on the electrode. The prepared sol-gel sensors were excellent in both stability and sensitivioty. This preparation method was applied to the construction of multiarray biosensors with detection units of glucose, cholesterol, total cholesterol, and urate, and of orthophosphate, total orthophosphate, and ammonia, and the construction of freshness sensors of fish and meat.
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