Needle Glucose Biosensors Based On Carbon Nanotubes

Diabetes is the world's 3^rd largest high attack of chronic diseases. In the therapyof diabetes, periodic testing and monitoring is indispensable. Because extracting venous blood continually brings great pain to the severe diabetics, a device for continuous in vivo monitoring of glucose concentration in people with diabetes has been research priority. Currently the biosensor is such monitor assistor.In this thesis, we made a new type of glucose needle biosensor based on carbon nanotubes. And we got a better component ratio through various optimization and screening tests. The results of this biosensor had a much larger linear range and better sensitivity.We immobilized GOD on the electric mixture of carbon nanotubes (MWNTs) and graphite powder, and sealed it in the glass capillary to construct the glucose biosensors. from serial of experiment, we confirmed that the electrode had best conductance when the proportion between MWNTs and graphite powder was 2:1. We added the mixture into GOD solution (pH 5.5), and mixed them for 8 hours, then centrifuged and the supernatant removed. After freeze-dried the mixture, finally we got GOD-absorbing composite. Then we added 1/5 GOD powder in the composite, and construct the biosensor by this optimal mixture. We found this kind biosensor satisfied the request for sensitivity and stability. The current response didn't decline, even after 24 hours of continual polarization experiment.In this paper, we preliminarily constructed a new type of glucose needle biosensor based on carbon nanotubes. Our experiments led to the satisfying results, but it's also far from practical application, and it needs further in-depth work in the future.