| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系所 === 106 === In order to reduce the side effects of chemotherapy, targeted therapies have received attention. In previous studies, cancer treatment drugs such as paclitaxel, doxorubicin-chitosan complex, and cisplatin have been deposited on titanium alloys as a vascular stents by electrochemical methods for the local treatment of tumors, Through drug sustaining release, in vitro tests have revealed the apoptosis of cancer cell to inhibit the cancer metastasis.
In this study, Ti coated quartz crystal resonator for the cathodic polarization test coupled with Quartz Crystal Microbalance (QCM) is used to investigate the electrochemical reactions and the related deposition mechanism more concisely and precisely. The field emission scanning electron microscope is used to observe the surface morphology and analyze the elements, Based on the reliable calibration curve, the drug loading is measured by using a spectrophotometer (UV-visible spectrometer).
There are 3 major discoveries described as the following. 1. The over load of QCM lasting for several seconds is observed for the cisplatin deposition at the initial cathodic reaction stage. It is speculated that the absorbed oxygen atom on Ti reacts with the coordinated water on cisplatin to form OH- ions which attract each other by strong hydrogen bands during the initial cathodic reaction, finally making the quartz crystal microbalance an over load. However, the OH- originally coming from coordinated H2O is unstable, and easily repelled by Cl- due to the repulsive coulomb force. In a few seconds, OH- ions diffuse into bulk solution and the hydrogen bond with OH- absorbed on Ti collapses. When OH-, increasing in solution, can replace Cl- to form (NH3)2Pt(OH)2, the stable deposition proceeds on the titanium. 2. From the QCM, the efficient deposition of cisplatin or paclitaxel appears in the reduction region of O2 and H2O. After oxygen purging, the loading of cisplatin is increasing since more produced OH- can replace Cl- for the diposition. However, the loading of paclitaxel is decreasing since the more OH- in solution will be attracted by the alcohol on solvated paclitaxel and deplete the hydrogen bond which is necessary for the deposition. 3. The potential of doxorubicin deposition can be more accurate through the QCM, and its deposition process is illustracted by figures to simulate the related mechanism.
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