Application Of Controllable Nanomaterials In Biosensors

Diabetes mellitus is a common and frequently-occurring disease and incidence of which is obviously increasing as the economy develops, standards of living are improved and the population of elder increases, and considered as the second grave killer of human lives except for cancers. It seriously menaces the healthy of the human beings, therefore, the diagnosis and treatment of diabetes mellitus is a heavy responsibility for the biomedical engineering field of the world. Long-term researches of clinic suggest that Diabetes mellitus and syndrome could be controlled if blood sugar concentration can be controlled within natural and physiological range. Glucose biosensor is the major technique for glucose analysis in clinical practice, for the advantages of glucose biosensors are obvious: high specificity, short time, simplicity and low cost of analysis, etc. One of the developments of glucose biosensor is the third generation amperometric enzyme electrode with direct electron transfer, which is commonly prepared by conducing organic salts and conducting polymers. Another development of biosensor is miniaturization and integration. Development of a third generation enzyme electrode is one of the long-term goals of biosensor program in the world. It is very necessary to search new methods to prepare the third generation biosensor.Since Clark and Lyons reported their enzyme electrode for measuring glucose in 1962, an enormous amount of papers have been published concerning enzyme-based biosensors. Glucose is by far the most studied analyte in this field of research. Currently, various studies were conducted to immobilize the biologically active components onto the transducing part of the biosensor device. Immobilization of enzyme is very pivotal to prepare biosensors. Development of nanomaterials provides a opportunity for immobilization of enzyme and makes the demands of reliable miniature sensors possible. Because nanoparticles are different from bulk materials. The special construction of the nanoparticles leads to four effects: surface, volume, quantum size, and quantum tunnel effects. These derive many unique properties: special mechanical, electric, magnetic, thermal, optical and chemical activity properties and so on. So many investigators make the most of the particles with the unique properties of large ratio of surface to volume, high surface reaction activity, surface active multicenters, high catalytic efficiency, and strong adsorption ability, and introduce various nanoparticles into immobility of enzyme , such as Au,Ag,Pt,SiO2,carbon nanotubes,conductive polymers and composites.In this work, we introduce ZnO which are prepared by reverse micelle and Au nanoparticles with different shapes into glucose biosensors. ZnO nanoparticle is a typical semiconductor Electric conductivity of which is between that of conductors and that of insulators. ZnO behave many particular characters when size of ZnO is minished to nano level. Gold nanoparticles have attracted much attention in the past few years owing to their particular physical and chemical properties and potential applications in many fields such as electronics, catalyst, magnetic materials and medicament transfer and so on, compared with bulk gold.Among them, biosensor is one of the most useful sections. The experimental results show that ZnO nanoparticles and Au nanoparticles with different shapes can significantly enhance the catalytic activity of the immobilization enzyme and the electrode has a very good response to the concentration of glucose solution., so these results provide an academic foundation for application of biosensors in future.