Research Of Self-Assembly Film Based On Biotin-Avidin System And Its Applications On Biosensor

The biotin-avidin system (BAS) has the especial appetency, great link and amplificatory function. Meanwhile, most proteins, enzymes, antibodies and DNAs can be linked with biotin easily, which do not decrease their activities. Therefore, BAS can be widely used in the fields of biology, molecular biology, biochemistry and medicine. In this paper, the self-assembly film based on BAS was researched. Furthermore, the biosensor based the technology was applied to test the strength of glucose and the activity of telomerase. BAS and the effect of nano-Au were combined in the experiment. A series of processes of glucose oxidase (GOx) immobility base on BAS were monitored by quartz crystal microbalance (QCM). The impacts such as the strength of avidin and bio-GOx, the effect of biotin and the modification of nano-Au, were discussed. The results show that it is beneficial to immobilize enzyme by BAS and the enzyme of immobility doubled after nano-Au modification. The GOx biosensor was prepared based on BAS. The electrode was charactered by cyclic voltammetry (CV). The conditions such as temperature, pH value, ionic strength and layers of enzyme, which affected the strength of biosensor's current, were studied. The ranger of detecting, the sensitivity and the stability of electrodes were tested. The results show that the biosensor has a fast current response of 6 s and linear calibration range of 5.0×10-4 to 4.0 × 10-3 M. It has advantages of sensitivity and quick response. Based on bio-dATP, the telomere DNA of Polymerase Chain Reaction (PCR) under the activity of telomerase was labeled by biotin. The activity was examined by the biosensors including QCM and IAsys, which was an innovative technique. The results mean that it is convenient for diagnosing the activity of telomerase to apply the biosensor. The biosensor has a beneficial sensitivity and the fast response time by the modification of nano-Au. It can distinguish the different telomerase with varied activities. Its limit for telomerase activity can be optimized.