The Preparation Of 5,7-Dinitro-2-Sulfo-Acridone And Its Application In The Electrochemical Sensor

Electrochemical DNA biosensor is a new sensor technology and gradually developed in recent decades. Due to it exhibits many advantages such as simplicity, low cost, rapidity of response, selectivity and so on, they are attracted considerable value and attention in virus detection, early diagnosis of diseases, environment detection and drug analysis. It based on nucleic acid hybridization, which is one of the most important biomolecular recognition processes. The biosensors is designed by the immobilization of ssDNA probes on different electrodes surface, and using electrochemically active indicators to measure the hybridization events between capture probes and their complementary DNA fragments. Therefore, immobilization technology of ssDNA probes, the use of hybridization indicators, sensitivity and selectively were key parts of the design of electrochemical sensors.In the first part, a new acridone derivatives was synthesized and used as an electrochemical hybridization indicator. Because a ring-opening reaction easily occurs between the acridine ketones compounds and the nuclear reagent, it has good chemical activity. And it is a kind of strong fluorescent dye, due to its macrocyclic conjugate system, which had application value. But a lot of acridone derivative have no applications in the field of DNA hybridization detection, especially the electrochemical field, because of little electrochemical activity. In the current study, 5, 7 Dinitro- 2-Sulfo- Acridone, DSA, is synthetized by Acridone structure, for improving its electrochemical activity. According to the structure of the DSA by ir, uv, fluorescence spectra, elemental analysis, mass spectrometry, furthermore, DSA photoelectric properties were studied here.In the second part, based on the study of the first chapter, as a new method of electrochemical probe, DSA has been proposed for the determination of salmon sperm DNA based on its interaction with DSA. The study shows that a new electrochemically non-active complex is formed via the intercalation of DSA with DNA. The decrease of oxidative peak currents of DSA is proportional to the concentration of DNA. Itexhibited a good linear relationship between the decrease currents and the logarithm of DNA concentrations with a detection limit as low as 0.002 ?g/mL. The binding number and the binding interaction mechanism are also discussed. DSA can be used as a novel DNA electrochemical hybridization indicator.In the third part, by coupling DSA intercalators as molecular tags, a DNA electrochemical biosensor was developed for ultra-high sensitively and selectively detection for breast cancer-related target sequences c-erbB2 with triple signal amplification. The electrocatalysis of nano-L-lysine(PLLy) modified GCE make the first signal amplification. ExoIII enzyme assisted target sequence cycles make the second signal amplification. Long-range self-assembled DNA super “Sandwich”nanostructures which can embed a large number of DSA to generate strong electrochemical signal make the third signal amplification. The result shows that under the optimum conditions, the linear range of the sensor is 2 a M-50 fM with the detection limit 0.5 aM. Furthermore, the sensor exhibited an ultrahigh discrimination ability even against single-base mismatch sequence. All above properties make it a promising candidate for the ultralow detection of DNA in clinical real samples.