矽片/銀或磁鐵粒子之奈米複合物合成及其物理捕捉細菌應用

Synthesizing Nanohybrids of Silicate Platelets/Silver or Magnetic Iron-Oxide Particles for Physically Capturing Bacteria

陳玨伶(Chieh-Ling Chen)

指導教授 ： 林江珍

國立臺灣大學/工學院/高分子科學與工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.10294

摘要

近幾年，奈米複合材料廣泛於生物科技領域發展，例如：奈米銀粒子或是奈米磁性鐵粒子固定於脫層矽片上。脫層矽片包含奈米矽片(NSP)或是奈米雲母片(NMP)。奈米矽片經由蒙托土脫層而奈米雲母片經由氟化雲母脫層。奈米矽片的片徑為80-100奈米，而奈米雲母片為300-1000奈米，但兩者厚度皆為1奈米。NSP或是NMP具有物理貼附於細菌表面的特性，因此奈米金屬粒子/奈米雲母片(NMP)可以有不同之應用。
第一部份，將奈米銀粒子固定於奈米雲母片(NMP)之奈米複合材料可藉由表面增強拉曼散射(SERS)方式來偵測細菌的光譜訊號。在表面增強拉曼散射之偵測技術上，奈米銀粒子/奈米雲母片具有可撓性與三維熱點效應(尤其是z方向)，可以增加SERS偵測的靈敏度與穩定性。由於細菌的細胞壁化學成分有所差別，例如革蘭氏陽性菌(金黃色葡萄菌)及革蘭氏陰性菌(大腸桿菌)，SERS技術可以很快速地將其辨別出來。
第二部分，我們發現NMP具有非常優異的細菌捕捉能力。因此，我們利用磁性奈米粒子容易分離的特性，合成新穎的奈米磁性鐵粒子/奈米雲母片用於捕捉水中的細菌。在NMP水溶液中以原位(in situ)聚合方式，共沉澱二價及三價鐵離子鹽類，將使奈米磁性鐵粒子(Fe3O4)緊密附著於NMP表面，奈米磁性粒子粒徑大小約為8.3奈米。NMP-Fe3O4奈米複合物可以在水中捕捉且將細菌聚集成團，並藉由磁鐵可將捕捉之細菌分離出來。將NMP-Fe3O4奈米複合材料加入104 CFU/mL金黃色葡萄球菌之菌液，經由磁鐵分離後可使菌量大幅下降至100 CFU/mL。由掃描式電子顯微鏡(SEM)可以觀察NMP與細菌表面緊密的貼附。因此，此新穎的磁性Fe3O4/NMP奈米複合材料將可輕易且快速地將水中之細菌分離。

關鍵字

奈米矽片 ； 奈米銀粒子 ； 表面增強拉曼 ； 奈米磁矽鐵粒子 ； 捕捉細菌 ； 分離細菌

並列摘要

Nanohybrids have been widely developed for biotechnology uses in recent years. Various nanohybrids are synthesized by embedded silver nanoparticles (AgNP) or iron oxide nanoparticles (Fe3O4) on the exfoliated silicate clay nanoplatelets. The exfoliated silicate clay nanoplatelets include nanoscale silicate platelets (NSP) from Montmorillonite and nanoscale Mica platelets (NMP) from the fluorinated Mica, which exhibit different lateral dimension of 80-100 nm for the NSP and 300-1000 nm for the NMP with the same thickness of 1 nm. The NSP or NMP nanohybrids are enabling of physically adhering onto to bacterial surfaces and resulting different applications, such as bacterial separation and detection.
In the first part of this study, novel nanohybrids of silver nanoparticles (AgNP) on the nanomica paltelets (NMP) can provide label-free analysis of bacteria via surface-enhanced Raman spectroscopy (SERS). The AgNP/NMP with flexibility and three-dimensional (3D) hotjunctions (particularly in z-direction) were discovered for improving the stability and enhancing of the sensitivity of the SERS nanotechnology. The SERS profiles recorded by such a platform are sensitive and stable, that could readily reflect different bacterial cell walls found in gram positive (S. aureus) and gram negative bacteria (E. coli).
We further observed the unexpected bacterial capturing behavior for NMP, prepared from the exfoliation of layered structure of Mica clays. The new class of the nanohybrids comprising of the structurally exfoliated nanoscale Mica platelets (NMP) and magnetic iron-oxide nanoparticles (Fe3O4) were synthesized and employed for capturing bacteria in water. The in situ co-precipitation of aqueous Fe2+/Fe3+ salts subsequently afforded Fe3O4 of ca. 8.3 nm in diameter, tightly attached NMP surface. It was demonstrated that the NMP-Fe3O4 nanohybrids enabled to capture and aggregate the bacteria in water into lumps that became maneuverable and removable by a magnet. A single clycle of the nanohybrids treatment and subsequent magnetic removal was shown the reduction of the bacteria (Staphylococcus aureus, SA) from the concentration of 104 to 100 CFU/mL. The intensive adhering force of NMP and bacterial surface was also observable by using scanning electron microscope (SEM). The magnetically maneuvering the microbes through the association with the Fe3O4/NMP implies the potential design of new devices enabling the removal of microbes from water medium.

並列關鍵字

nano-silicate-platelets ； silver nanoparticles ； surface-enhancing raman scattering ； magnetic iron oxide nanoparticle ； bacterial capturing ； bacterial separating

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