ENFET glucose biosensor produced with mesoporous silica microspheres

The biosensors based on ENFETs for direct glucose oxidase (GOD) concentration analysis have been fabricated. Mesoporous silica (MS) microspheres of different pore sizes were used as the substrates for immobilizing enzyme to construct ENFETs. The MS microspheres show significantly improved enzyme immobilization capacity. The glucose sensitive ENFET based on the modification of the gate surface of ion-sensitive field-effect transistors (ISFETs) with MS microspheres and glucose oxidase (GOD) shows obviously enhanced sensitivity and extended lifetime compared with the conventional ones. MS microspheres of different pore sizes were investigated and the sensor with remodeled MS microspheres which experienced the pore expanding treatment show better performance than untreated MS microspheres. The fabricated sensors have a linear range of 0.25–2.0 mM, and a detection limit of ca. 0.10 mM. The influence of buffer concentration, ionic strength and pH was discussed. The biosensor also has good stability and reproducibility.