Synthesis Of Iron Oxide Nanocomposites And Their Application In Biomedicine

So far,malignant tumors are still one of the major problems that threaten human health.For decades,although researchers have devoted great energy to numerous studies,the problems have not been significantly ameliorated,and the increment of the incidence of tumors becomes severe year by year.One of the reasons making it difficult for tumors to be cured is that they are difficult to be diagnosed effectively in advance.Usually the tumor cells begin to spread when people discover that they have reached the terminal situations of the cancer,which significantly increases the difficulty of the treatment of tumors.Therefore,the early diagnosis of tumors is very important and desperate.In addition,surgery,radiotherapy and chemotherapy are still the main treatment methods for tumors,which might cause damage to normal tissues while killing tumor cells,causing serious side effects.Photothermal therapy,as an emerging method for tumor treatment,uses photothermal reagents to absorb the energy of near-infrared lasers to produce localized hyperthermia and induce apoptosis of tumor cells.The combination of multiple therapies can be more effective in improving the efficiency of tumor treatment and reducing toxic side effects on normal cells and tissues.Based on magnetic Fe₃O₄ and Fe₃O₄@Ag,this thesis explores their effects on the initial diagnosis,imaging and synergistic treatment of tumors,and mainly contains the following:1.Porous iron oxide is used as a carrier to load doxorubicin hydrochloride,and owing to its broad absorption peak in the near-infrared region,part of the light energy can be converted into heat energy,therefore the local temperature of the tumor site can get increased.At the same time,the increment of the temperature can promote the release of doxorubicin hydrochloride,so as to achieve the effect of synergistic treatment of photothermal/chemo therapy.In addition,porous iron oxide has a large r₂ value and is a good T₂ contrast agent in application of MRI.2.Porous iron oxide is used as a template,in situ reduction of AgNO₃ on its surface to form Ag nanoparticles,thereby obtaining Fe₃O₄@Ag nanocomposites.And then used it as a H₂O₂ sensor to study the sensitivity and selectivity of its catalytic performance.In addition,it is further applied to the detection of the content of H₂O₂ inside the living cells to determine whether the cells have lesions,and ultimately achieve early initial diagnosis of diseases?tumors?.