藉由幾丁聚醣還原奈米銀做為生物感測器

Synthesis of Ag NPs by Chitosan for Bio-Sensing Application

蔡喬修(Tsai, Chiao Hsiu)

指導教授 ： 游萃蓉

國立清華大學/工學院/材料科學工程學系/碩士(2015年)

摘要

本研究利用高生物相容性 (biocompatibility) 之幾丁聚醣 (chitosan) 還原具有表面電漿共振效應 (surface plasmon resonance effect) 的奈米銀做為肉眼辨識的生物感測器。且在此研究中利用不同濃度的人類血清白蛋白 (human serum albumin, HSA) 與chitosan進行接合來驗證此生物感測器檢測蛋白質的可行性，並使用穿透式電子顯微鏡 (transmission electron microscopy, TEM) 與紫外/可見光吸收光譜儀 (UV-Vis) 來探討其檢測機制。此外，本實驗亦將UV-Vis之光吸收圖譜轉化為色座標 (chromatic diagram) 來定量HSA的濃度。
本研究中首先探討chitosan還原奈米銀的反應機制，接著探討接合HSA之chitosan對還原奈米銀反應的影響。隨chitosan接合不同濃度的HSA，其所還原出奈米銀之粒徑分布及數量亦不相同，而造成奈米銀在顏色上會根據HSA的接合濃度而有明顯差異。且本研究也透過TEM和UV-Vis分析，進一步了解HSA影響chitosan還原奈米銀的機制。
本研究利用chitosan還原奈米銀的反應應用於比色法生物感測器 (colorimetric biosensor)。其機制為當HSA接合於chitosan上時會阻斷chitosan上能還原奈米銀的位置，且接合越多HSA，奈米銀就無法被還原。另外，亦可以透過改變chitosan濃度來調控HSA檢測區間。
本研究中，以HSA為待測物並利用chitsan接合HSA之後會生成不同顏色之奈米銀之特性，期望可以發展出肉眼辨識、方便使用、快速檢測且低成本讓每個人都能擁有之生物感測器，得以隨時了解自己身體的健康狀況。

關鍵字

生物感測器 ； 奈米銀 ； 幾丁聚醣 ； 顏色變化

並列摘要

In this study, silver nanoparticles (Ag NPs), which were synthesized by biocompatible chitosan, showed strong surface plasmon resonance (SPR) effect and were used to develop a naked-eye biosensor. Human serum albumin (HSA) with different concentrations were conjugated with chitosan to demonstrate the feasibility of protein sensing. The mechanism of Ag NP synthesis by HSA-conjugated chitosan was studied via UV-Vis spectra and TEM analyses. Furthermore, the UV-Vis spectra were transformed to chromatic diagram to characterize the color of synthesized Ag NPs to correlate the HSA concentration.
In this work, the mechanism of Ag NP synthesis by chitosan was discussed in the first instance, followed by the study on the effects of HSA-conjugated chitosan. The result showed that HSA with different concentrations restrained the reaction of Ag NP formation to different extent and therefore led to the color changes. Furthermore, UV-Vis and transmission electron microscopy (TEM) were used to analyze the Ag NPs to demonstrate the restraining effect caused by HSA.
Moreover, the effect of HSA on restraining the chemical reduction to form Ag NPs was applied to develop colorimetric biosensor. Through synthesis of Ag NPs in chitosan, which was conjugated with HSA of different concentrations, the lighter colors of Ag NPs were observed when the conjugating concentration of HSA is higher. The severe color change occurred when the formation of Ag NPs was completely retarded. Furthermore, the detecting range is adjustable through tuning the concentration of chitosan.
In summary, this study addresses a new mechanism that the synthesis of Ag NPs by chitosan would be restrained by conjugating proteins on chitosan to provide a naked-eye, convenient, instant-detecting and cost-effective biosensor for everyone.

並列關鍵字

Biosensor ； Ag Nanoparticles ； Chitosan ； Colorimetric

參考文獻

[1] L. C. Clark, Jr., and C. Lyons, “Electrode Systems for Continuous Monitoring in Cardiovascular Surgery.”, Ann. NY. Acad. Sci., 1965, 102(1), 29-45

[2] J. H. T. Luong, K.B. Male, and J. D. Glennon, “Biosensor Technology: Technology Push versus Market Pull”, Biotechnol. Adv.,2008, 26, 492-500

[4] Khetani, R. Salman, Sangeeta N. Bhatia. "Microscale culture of human liver cells for drug development." Nature biotechnology, 2007, 26 (1), 120-126.

[5] Rockey, C. Don, D. Montgomery Bissell. "Noninvasive measures of liver fibrosis." Hepatology , 2006, 43 (1), 113-120.

[7] I. Moser, G. Jobst, P. Svasek, M. Varahram, G. Urban, “Rapid Liver Enzyme Assay with Miniaturized Liquid Handling System Comprising Thin Film Biosensor Array”, Sensor Actuat. B, 1997, 44, 377-380.