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Synthesis and Evaluation of Molybdenum Disulfide for Combined Photothermal-chemo Therapy

Salimi, Marzieh | 2022

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 55499 (48)
  4. University: Sharif University of Technology
  5. Department: Institute for Nanoscience and Nanotechnology
  6. Advisor(s): Vosoughi, Manouchehr; Shokrgozar, Mohammad Ali; Delavari, Hamid
  7. Abstract:
  8. New methods of cancer treatment are always the attention of researchers all over the world, among which the photothermal treatment method is of particular importance. In addition to being easy, this treatment method has the least invasiveness. Studies have shown that combining this method with other methods such as chemotherapy not only can be very effective in destroying tumor tissue, but can significantly reduce the side effects of chemotherapy drugs.In order to apply the photothermal treatment method, an effective photothermal agent is needed. Molybdenum disulfide nanosheets have performed successfully in this field, which have been of great interest, due to their high efficiency in converting light into heat. These nanosheets are biocompatible and due to their high surface-to-volume ratio, they are able to act as a suitable carrier for chemotherapy drugs. Also, if the surface of this nanostructure is modified by using temperature-sensitive agents, it is possible to provide the controlled release of the drug.In this research, molybdenum disulfide nanosheets and nanoflowers were synthesized and then chemically and structurally investigated. According to the obtained results, molybdenum disulfide nanosheets have an extinction coefficient of 19.06 L/g.cm and a photothermal efficiency of 25.68%, while the extinction coefficient and photothermal efficiency obtained for molybdenum disulfide nanoflowers are 5.09 L /g.cm and 13.77%, respectively. According to the results of X-ray photoelectron spectroscopy, the ratio of conductive to semi-conductive phase in nanosheets is 2:1 and in nanoflowers 1.2:1. Therefore, the higher proportion of conductive phase in nanosheets increases their photothermal efficiency compared to nanoflowers. Next, molybdenum disulfide nanosheets were used as a more effective light-to-heat agent, and the non-specific chemotherapy drug doxorubicin hydrochloride along with 1-tetradecanol fatty alcohol, which is a temperature-sensitive agent, were loaded on the nanosheets. The drug loading capacity on nanosheets without 1-tetradecanol coating and with 1-tetradecanol coating was 122% and 184%, respectively. Coating of 1-tetradecanol did not change the structure and photothermal properties of molybdenum disulfide nanosheets. According to the results obtained from the drug release profile, the largest amount of drug is released in hyperthermia temperature and at the tumor site with an acidic pH of 5.5, so that after 48 hours, about 60% of the drug is released in the environment. This is despite the fact that in normal body temperature and pH conditions, only about 12% of the drug is released after 48 hours, and this shows that 1-tetradecanol can prevent the premature release of the drug in physiological conditions of the body. The results showed that infrared light radiation has a wide effect on drug release so that after 30 minutes of laser radiation with a power of 1 W/cm2 and in an acidic environment, 34.75% of the drug is released. Also, the obtained results showed that the prepared nanostructure is completely biocompatible and after 24 hours, more than 90% of normal L929 cells and MCF7 cancer cells exposed to a high concentration of 150 µg/mL of this material, survived. This nanostructure is able to cause the death of cancer cells due to the two factors of temperature and pH in a controlled manner so that only 10% of MCF7 cells exposed to this nanostructure and under infrared laser radiation survived. Therefore, this nanostructure can be used as a suitable option for simultaneous and controlled chemotherapy and photothermal methods.
  9. Keywords:
  10. Nanosheet ; Molybdenum Desulfide ; Stimuli-Responsive ; Cancer Chemotherapy ; 1-Tetradecanol Alcohol ; Controlled Release ; Cancer Treatment

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