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  • 學位論文

仿酵素活性之鹵素鉍氧化物奈米複合材料的合成於檢測和抗菌之應用

Synthesis of bismuth oxyhalide-based nanocomposites with enzyme-like activity for sensing and antibacterial applications

指導教授 : 張煥宗

摘要


本論文著重在合成及製備可調控過氧化酶(peroxidase-like, POX)及氧化酶(oxidase-like, OX)活性之鹵素鉍氧化物(bismuth oxyhalides, BiOX, X代表氯,溴,碘)奈米複合材料(nanocomposites)。此仿生催化材料可分別在有或無過氧化氫(H2O2)的環境下,將不具螢光的10-乙醯基-3,7-二羥基吩嗪(Amplex Red, AR)氧化成帶有螢光的試鹵靈(resorufin)。再將仿生奈米複合材料藉由螢光變化檢測蛋白質及重金屬,也進一步將其作為抑制細菌活性的抗菌試劑。第一章內容是探討金奈米粒子及鹵素鉍氧化物奈米材料的特性及應用。第二章則是將具適合體修飾之金奈米粒子(aptamer-modified gold nanoparticles, AptAu NPs)與鉍離子、氯離子於水溶液環境中反應,合成自組裝的適合體金奈米粒子/鉍氧化氯複合奈米材料(AptAu NPs/BiOCl nanocomposites)。AptAu NPs/BiOCls奈米複合材料具催化活性,於過氧化氫環境中,能催化過氧化酶基質形成螢光產物。此複合材料相較於單純AptAu NPs或BiOCl片狀物,其催化活性大於90倍,顯示AptAu NPs/BiOCl奈米複合材料具有協同效應並可利用Au NPs上的適合體(Del-5-1 and v7t-1)與內皮生長因子(vascular endothelial growth factor-A165, VEGF-A165)結合後改變催化活性。10-乙醯基-3,7-二羥基吩嗪/過氧化氫適合體金奈米粒子/鉍氧化氯複合材料(AR/H2O2AptAu NPs/BiOCl nanocomposites)於偵測VEGF-A165具高度選擇性(與其他蛋白質相比 > 1000倍)且靈敏度好。第三章內容為合成鉍氧化碘奈米網狀結構(BiOI nanonetworks),並加入金屬離子後使其沉積金屬原子/離子或金屬奈米粒子在鉍氧化碘奈米網狀結構上進而調控其活性。BiOI 奈米網狀結構的過氧化酶催化活性與鉍氧化氯(BiOCl)、鉍氧化溴(BiOBr)奈米片狀材料相比大於425倍。合成金奈米粒子/鉍氧化碘奈米複合材料(Au NPs/BiOI nanocomposites)可使其氧化酶活性提高至少10倍,而在製備時分別加入鎳、鋅、錳離子於BiOI奈米網狀結構則可提高過氧化酶催化活性至少3倍。Au NPs/BiOI 奈米複合材料及氧化鎳奈米粒子/鉍氧化碘奈米複合材料(NiO NPs/BiOI nanocomposites)可分別偵測汞離子與鉛離子至nM等級,也可在不同水樣中進行重金屬檢測。第四章是利用金離子、鉍離子和碘離子以一步合成法製備金/鉍氧化碘奈米複合材料(Au/BiOI nanocomposites),其氧化酶活性與單純BiOI奈米片狀材料相比可高達4倍。具氧化酶活性之Au/BiOI奈米複合材料,是由Au與含有氧空缺(oxygen vacancies)的BiOI奈米材料所組成。Au/BiOI 奈米複合材料皆可抑制大腸桿菌、克雷伯氏肺炎菌、沙門氏菌、金黃葡萄球菌、枯草桿菌及多重抗藥性金黃葡萄球菌等,其最小抑菌濃度與BiOI奈米片狀材料相比低於4000倍。Au/BiOI奈米複合材料可和細菌結合,且產生活性氧物種(reactive oxygen species, ROS)而破壞細菌。此材料不管在體外和體內測試都具有高度生物相容性,在兔子眼睛以金黃葡萄球菌誘發的細菌性角膜炎也能有效減緩其症狀,極具潛力成為眼睛細菌感染相關疾病之抗菌試劑。

並列摘要


This disssertation focus on the preparation of switchable enzyme-like activity of bismuth oxyhalides (BiOX, X = Cl, Br, I) nanocomposites that exhibit peroxidase-like (POX) or oxidase-like (OX) activity. The BiOX nanomaterials facilitate catalytic conversion of Amplex Red (AR) to fluorescent resorufin in the presence or absence of H2O2. Enzymimic nanomaterials are further applied for the detection of proteins, and heavy metal ions. The nanomaterials also acts as antimicrobial agent. Chapter 1, the detailed background of bismuth oxyhalide nanomaterials including their catalytic properties and applications is reviewed. Chapter 2, the self-assembled gold/bismuth oxychloride nanocomposites are prepared from an aqueous mixture of aptamer-modified gold nanoparticles (AptAu NPs), bismuth ions and chloride ions. AptAu NPs are immobilized on bismuth oxychloride (BiOCl) nanosheets in situ to form AptAu NPs/BiOCl nanocomposites. The synergistic effects of AptAu NPs/BiOCl nanocomposites leads to at least 90-fold higher POX-like activity than AptAu NPs or BiOCl nanosheets. Catalytic activity of AptAu NPs/BiOCl nanocomposites is suppressed by vascular endothelial growth factor-A165 (VEGF-A165) molecules that specifically interact with the aptamer units (Del-5-1 and v7t-1) on the nanocomposites surface. AR/H2O2AptAu NPs/BiOCl nanocomposites probe shows high selectivity (>1000-fold over other proteins) and sensitivity (detection limit ~0.5 nM) for the detection of VEGF-A165. Chapter 3, we demonstrate enzyme-like activity of BiOI nanonetworks that can be regulated through homogeneous deposition of metal atoms/ions or nanoparticles. BiOI nanonetworks exhibited much stronger (425-fold) POX-like activity than BiOCl or BiOBr nanosheets. In situ formation and deposition of Au NPs onto BiOI nanonetworks enhanced the OX-like activity of the nanocomposites. The deposition of metals such as Ni, Zn or Mn on the BiOI nanonetworks boosted their POX activity by at least 3-fold. Au NPs/BiOI nanocomposites and NiO NPs/BiOI nanocomposites were used for the detection of heavy metal ions such as Hg2+ and Pb2+, respectively. These BiOI nanocomposite-based probes allow selective detection of Hg2+ and Pb2+ down to nanomolar quantities. The practicality of the probes is validated in environmental water samples. Chapter 4, we developed a simple one step route to prepare Au/BiOI nanocomposites from an aqueous mixture of gold ions, bismuth ions and iodide ions. Au NPs were in situ formed and doped into BiOI nanonetworks that exhibited ca. 4-fold higher OX-like activity than BiOI nanosheets. OX-like Au/BiOI nanocomposites were prepared by doping of gold and generation of oxygen vacancies in BiOI nanostructures. Au/BiOI nanocomposites show wide spectrum antimicrobial activity against nonmultidrug-resistant E. coli, K. pneumoniae, S. enteritidis, S. aureus, and B. subtilis bacteria and multidrug-resistant bacteria, as well as methicillin-resistant S. aureus (MRSA). Minimal inhibitory concentration value of Au/BiOI nanocomposite is much lower (>4000-fold) than BiOI nanosheets. Au/BiOI exhibits synergistic effect through strong interaction between nanocomposites and bacterial membrane that cause the disruption and generation of reactive oxygen species (ROS). In vitro and in vivo cytotoxicity, rabbit corneal keratocytes and hemolysis assays evaluation by using the rabbit eye model revealed superior biocompatibility of Au/BiOI nanocomposites, suggesting that it can effectively alleviate S. aureus induced bacterial keratitis in rabbits.

參考文獻


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Chapter 1
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[3] Li, K.; Xu, Y. L.; He, Y.; Yang, C.; Wang, Y. L.; Jia, J. P. “Photocatalytic fuel cell and dye self-photosensitization photocatalytic fuel cell with BiOCl/Ti photoanode under UV and visible light irradiation” Environ. Sci. Technol., 2013, 47, 3490–3497.

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