Research Of Bio-barcodes Amplification Technique For The Detection Of Tumor Biomarker CEA

Detection of tumor markers, involve in cancer diagnosis, genetic screening, cancer therapies evaluation and other fields. However, conventional methods of analysis are limited due to high costly, complicated operation, time-consuming. Therefore, the development of new cancer diagnosis detection methods attracts extensive attention. To achieve sensitive, accurate, convenient and economical detection has become increasingly urgent demanding in biochemical fields. In recent years, the development of signal amplification detection technologies based on various enzymes and nanoparticles, offered a new opportunity to achieve simple, fast, and highly sensitive detection of nucleic acids. In this thesis, a series novel, rapid and sensitive detection methods for tumor marker CEA based on bio-barcodes technique by electrochemical analysis were constructed, and realized accurate and effective detection of CEA.The main contents were summarized as follows:(1) As the detection of tumor markers do great contribute to ensure human health, a series of recent progresses about the detection of tumor markers were presented in introduction part. Then, the concept of bio-barcodes and research progresses of bio-barcodes based detection technique were mainly discussed. Furthermore, the compare of bio-barcodes based detection technique with other conventional techniques for biochemicals analysis was discussed in introduction part of this thesis.(2) An electrochemical immunosensor based on bio-barcodes for signal amplified to detect hIgG was constructed in this section. We combined electrochemical methods with bio-barcodes technique to make the structures like sandwichs. Due to the advantage of DNA bio-barcode signal amplification technology and large surface area of gold nanoparticles, the sensitivity of immunosensor was increased. The method broke through the disadvantages of traditional of immunoassay in the process detection hIgG, such as expensive equipment, operation trival and other shortcomings. This new biosensor has low detection limit, good stability, is expected to be used to detect other biochemical substances.(3) An efficient and sensitive electrochemical immunosensor which based on bio-barcodes signal amplification technique with hybridization chain reaction to detect CEA was constructed. Hybridization chain reaction combined with electrochemical methods could make the reaction time greatly shorten and signal changed significantly. Differ from other DNA chain elongation reaction, this method does not require the participation of enzymes. This method has the versatility, just change the analyte can detect different antigens or other tumor markers. Therefore, it has broad application prospects in the field of early diagnosis of cancer.(4) A simple bio-barcodes amplification technique to detect CEA with the enhancement of silver nanoclusters method is established. Because the characteristic sequence contains special DNA base pairs, it can be effectively promote the growth of silver nanoclusters. This method is different from the previous silver-enhanced techniques; it could more convenient to achieve the detection for substance than other methods with rapidly and simply, possessing a great deal of excellent properties, such as high sensitivity, high selectivity, as well as reproducibility.