Study Of Tumor Markers Detection Based On Gold Nanoparticles Cage And Cell Imaging

Part1ATP is the smallest unit of energy. It is the energy source of all life cells’ activity,and it plays an important role to maintain normal organism function. After cell damageor death, the amount of ATP in cell will significantly reduce, so the change of ATPconcentration can be used to reflect the cell damage. Therefore, the changes of ATPconcentration can reflect the cell metabolism and the overall amount of cell killing incancer chemotherapy, and so on.Gold nanocage is a kind of cubic nanoparticles, possessing a hollow morphology,and having nanoporous on walls. It has great light absorption cross section, goodthermal properties, good biocompatibility, a very wide range of scattering andabsorption for light, and so on. The main jobs of this paper can be concluded asfollows:1. The synthesis of silver nanocubes and gold nanocagesThis article adopts the method that reduction of AgNO3by ethylene glycol for thesynthesis of nanocubes. The size of silver nanocubes was50-60nm. Then, Aunanocages were prepared using a remarkably simple galvanic replacement reactionbetween HAuCl4and Ag nanocubes. Through comparing the LSPR peak and TEM ofgold nanocages, it was proved that we have synthesized the gold nanocage, which hasgood morphology and an average diameter of60-70nm. 2. The fabrication of ATP biosensor based on the gold nanocages and itsapplication for ATP detection in cancer cellsIn this paper, the guest molecules were loaded in the hollow interiors of goldnanocages. To block the fluorescent molecules in the cages, the gold nanocages werewrapped with the thiol-modified DNA and its complementary strand. In order toseparate the probe from the solution, the gold nanocages were assembled withthiol-modified magnetic beads. Under the optimal conditions, the biosensor was ableto detect ATP in the range of5.0×10-8to1.0×10-6M. The sensor has great potentialapplications in the biomedical field and can be used for specific detection of differenttarget molecules. It provides new ways and methods for early diagnosis and treatmentof major diseases such as cancer.3. Fluorescence imaging by ATP probe in cellsAdding the probe into tumor cells cultures, the Laser Confocal ScanningMicroscope (LCSM) images of tumor cells were obtained. The images illustrate therelease of fluorescent molecular in tumor cells. The system is expected to be applied inthe treatment of major diseases such as cancer, achieving for targeted drug deliveryand controlled release.Part2GSH exists in all organisms living cells. Due to the particularity of its structure, itcan participate in a variety of physiological processes in the body. It plays an importantrole in maintaining the balance of sulphur and sulphide and the reducing environmentin organism. When diseases occurred in the body, the concentration of GSH will bechanged. So, detecting the concentration of GSH in cells has great importance. Thisarticle used a new compound of selenadiazole as electrochemical probe, whichcontaining Se-N bond. The decreased current signal of the electroactive material wasobserved with the increase of GSH concentration due to the consumption ofelectroactive compound by the nucleophilic reaction of GSH. The main jobs of thispaper can be concluded as follows:1. The electrode reaction process of the new electricactive compound and thereaction mechanism between the electricactive compound and GSHThe new compound [1,3] Dithiolo [4,5-f]-2,1,3-benzoselenadiazole-6-thione(DBT) containing the Se-N bond, has strong electrochemical activity. The novel developed electrochemical assay based on the strong nucleophilicity of sulfhydrylto cleave Se-N bond for electrochemical response is considerably attractive for rapid,sensitive，and selective detection of cellular thiol. Cyclic voltammograms（CV）andDifferential pulse voltammograms（DPV）were used to study the reaction mechanismof DBT and GSH. GSH could be quantified ranged from1.0×10-10to9.0×10-10M (R=0.9920) with good linearity.2. The detection of thiols in Ramos cellsIn order to study the detection effect of DBT in biological samples, we applyDBT to detecting the non-protein thiols of Ramos cells. Ramos cells contain relativelyabundant of thiols. The experimental results showed that DBT has a goodelectrochemical response in intracellular non-protein thiol detection. So, the newcompound can be used to detect non-protein thiol in the cancer cells.