Assay Of Sers Biosensor Based On Chain Replacement Amplification To Detect Telomerase

Tumor cells are caused by the normal cells that reproduce abnormally for uncontrol gene expression. Recent studies have found that the change of telomere play an important role for the unlimited proliferation of tumor cells. Telomerase can sythesis-TTAGGG-by itself as template to prevent it shortened or missing. So the living cells form tumor cells. The research by Hastie et al shows that the telomeres shorten sequence is an important symbol for the tumor. Therefore, the study of telomere and telomerase is very urgent and important. Biological sensors can detect the presence of telomerase, activity and concentration, which make a great contribution for clinical science, biological science and chemistry research.We studied simple and sensitive Raman sensors that detect the telomerase in this thesis, which base on the amplification effect of magnetic microspheres and gold nanoparticles and the silver of the Raman signal of the enhanced to reduce the detection limit. The following is the content of the paper:1.The biosensors based on the magnetic beads and gold nanoparticles amplification effect detect the concentration of the telomerase. While Hairpin DNA connecting with the magnetic microspheres, primer1matching the neck ring part and loosing the hairpin structure by continuous replication of telomerase growth. The gold nanoparticles connecting with primer2hybrid with uncomplementary base pairing in the hairpin DNA which grows under the function of DNA polymerase to replace the primer1,while the replaced primer1can use repeatedly. Finally, hairpin DNA connected to the magnetic microspheres will be opened entirely and gold nanoparticles can enhance the Raman signal. Detection range of2.0×10-14-2.0×10-12IU/mL, the lowest detection limit is2.0×10-14IU/mL, it shows better accuracy and feasibility.2.We also discussed the silver for enhanced Raman signal through forming the Au@Ag core-shell structure by deposit a layer of silver on the surface of gold nanoparticles. Detection limit of telomerase was reduced by3orders of magnitude. At the same time, the Raman sensor applied to detection of telomerase in Hela, obtained the good effect. And through forming the Au@Ag core-shell structure to applied to the biosensor, the detection limit of telomerase and Hela cell is5×10-17IU/mL,10cells/mL. This scheme can also be used in the detection of cells in a complex environment, and it is applicable to a large number of biological analysis for its high sensitivity, low cost, simple operation.3.This chapter studied multiple DNA detection using the Au@Ag core-shell structure. Due to a variety of joint detection of DNA,it made the detection method more sensitive and accurate due to a variety of joint detection of DNA. And Ag that deposited on the surface of gold nanoparticles by increasing the surface roughness increased surface area is coated MB and gold nanoparticle to enhance Raman amplifier signal, thus further increasing the signal.