四氧化三鐵奈米粒子之合成及應用研究

Abstract

近年來各種領域之科學家更加重視粒子之多功能化，例如於粒子表面建構不同之金屬或非金屬化合物之殼，以增加不同之性質，甚至進而促使兩物質作用，改變兩者之物性或化性形成特殊之核-殼(core-shell)結構。奈米粒子之表面修飾之應用，於生物醫學領域之使用相對重要，為提升奈米粒子對於生物之相容性與對生物之無毒性，使本質為無機材料之奈米粒子能於人體內之生存期可更久並不遭排斥，故奈米粒子表面修飾使多功能化與生物體之相容性更為當務之急。 本研究乃利用化學之高溫分解法還原部份之三價鐵離子，於高溫環境下經由溫和之還原作用，促使起始物進行核化與成長之反應而形成奈米粒子，過程中調控其生長溶液離子濃度與反應時間，利用穿透式電子顯微鏡觀察其成長過程之機制，並藉由控制成長溶液之濃度與成長溫度，進而合成出不同尺寸與狹窄粒徑分布之四氧化三鐵奈米粒子，最後將合成於有機相中之奈米粒子經由交換配位基之相轉移(phase transfer)方法將奈米粒子轉至水相中，一方面應用於生物化學方面之測試，便經過生物之細胞毒性測試(cytotoxic test)，探討其奈米粒子之尺寸效應(size effect)是否對生物體有所毒害，另一方面使四氧化三鐵表面包覆金之金屬殼，使得粒子具有磁性並有光學之雙重性質，所合成之產物均經由穿透式電子顯微鏡觀察其型態及粒徑、超導量子干涉磁量儀獲得粒子之磁特性與粒徑分佈之關係、利用同步輻射之光源測得粉體繞射之圖譜並分析其粒徑及結構與利用熱重分析、紅 外線光譜了解其不同粒子之粒徑組成等。

In this regard, there has been much interest among the scientists towards the synthesis of multifunctional composite materials using two or more materials e.g. core-shell particles. The core shell nanoparticles have been of great potential in bionanotechnology due to improvement in its biocompatibility and decreased toxicity on account of surface modification of core shell nanomaterials. The prolonged circulation time of inorganic nanomaterials in our body is important task in front of the scientists, which also needs surface modification. In the present thesis, the syntheses of Fe3O4 (magnetite) nanoparticles were carried out by controlling the reaction time and concentration of ferric cation using high temperature decomposition method. The morphology of nanoparticles was analyzed by transmission electron microscopy (TEM). The magnetic properties were measured by superconducting quantum interference device (SQUID) and X-ray magnetic circular dichrism (XMCD). The crystal structure of nanoparticles was explored by X-ray diffraction (XRD). The composition of nanoparticles were analyzed by thermal gravimetric analysis (TGA) and Infrared spectrum (IR). We have successfully prepared magnetite nanoparticles of different sizes which were then transferred from oil phase to aqueous phase for carrying out cytotoxicity studies on cancer cells. The part of the research also involves synthesis of core-shell Fe3O4@Au nanoparticles to exploit magnetic properties of core and optical properties of shell in diagnostic and hyperthermia of cancer.