不同氮含量螢光奈米鑽石製備及光譜特性研究與生物應用

Fabrication and Characterization of Fluorescent Nanodiamonds with Different Nitrogen Contents for Biological Application

蘇隆畯(Long-Jyun Su)

指導教授 ： 張煥正 ； 陳家俊

國立臺灣師範大學/理學院/化學系/碩士(2012年)

摘要

螢光奈米鑽石(fluorescent nanodiamond) 是一種擁有許多獨特性質的新穎奈米材料，螢光奈米鑽石具有極佳的光穩定性並具有非常好的生物相容性，而且其表面容易修飾一些特定的官能基團，如果我們能增加螢光奈米鑽石的螢光強度，將更有助於我們在生物標記(bio-label)上的應用。
具有 N-V0 及 N-V- 缺陷中心(defect center)的螢光奈米鑽石是最常使用的紅色螢光奈米鑽石(red-FND)，我們推估，如果增加奈米鑽石中的氮含量，有助於更多N-V0 及 N-V- 缺陷中心(defect center)產生，將使得螢光奈米鑽石放出的螢光強度更高，有利於我們在生物顯影上的應用。因此，我們利用擴散反射紅外線傅立葉轉換光譜法 Diffuse Reflectance Infrared Fourier Transform (DRIFT) Spectroscopy，偵測不同鑽石材料，並且依據單聲子區域 (1000-1400cm-1) 有獨自的特徵吸收峰來推算不同鑽石材料所含的氮含量，由於起初量測的鑽石粒徑均為10~40微米，因此我們再利用3維高能量球磨機 (3D-Ball mill machine)將這些不同氮含量的鑽石材料研磨並分離出粒徑約100奈米的不同氮含量奈米鑽石，接續再利用我們實驗室自行架設的離子佈植設備(40KeV Helium beam)將這些不同氮含量的奈米鑽石製作成不同氮含量的100奈米螢光鑽石，以利我們進行探討與應用。
經由本篇論文研究後，得知並非氮含量越高的螢光奈米鑽石其螢光強度就越強，根據研究指出，氮含量約為 ~157 ppm時 (Yellow RVD sample)，會有最高的螢光強度表現，其螢光強度為我們實驗室原本所生產的Ele6_100奈米螢光鑽石的兩倍；另外，我們直接將Ele6_100奈米螢光鑽石利用3維高能量球磨機研磨，經過處理後，可以得到30奈米螢光鑽石，其螢光強度為原始我們實驗室自行生產的35奈米螢光鑽石的3~4倍，因此我們不僅僅找尋到螢光強度更高的螢光鑽米鑽石，也成功地製備粒徑小、螢光強度高的30奈米螢光鑽石，以利我們接續的生物顯影以及光學上的研究及應用。

關鍵字

螢光奈米鑽石 ； 氮含量 ； 生物標記

並列摘要

Fluorescent nanodiamond (FND) containing a high density of negatively charged nitrogen-vacancy centers (NV–) as built-in fluorophores has recently emerged as a promising tool for bioimaging owing to its excellent photostability, high biocompatibility, and facile surface modification. However, compared to that of quantum dots, organic dyes, and fluorescent proteins, its fluorescent intensity is not sufficiently high enough for practical applications. In this thesis, we explore the possibility of increasing the density of NV– in FNDs by using nitrogen-rich type Ib diamond powders.
The nanodiamonds (size ~ 100 nm) used in this work were prepared by ball-milling of microdiamonds, in which the density of neutral, atomically dispersed nitrogen atoms ([N0]) was measured by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). These nanodiamonds, with known nitrogen densities of 100 − 400 ppm, were then converted to FNDs by radiation damage using a 40-KeV He+ beam, followed by thermal annealing. We found that the fluorescent intensity of the FND so prepared is not in linear proportion to [N0]. The FND with [N0] ~ 157 ppm has the highest fluorescence intensity, which is at least 2-fold higher than that of our standard FND samples made of diamonds from Element Six. Furthermore, an increase of the fluorescence intensity by 3 − 4 folds was achieved for 30-nm FNDs prepared by ball-milling of the 100-nm FNDs, compared to that of 35-nm FNDs prepared directly from pristine nanodiamonds. We conclude that the methods developed in this work can not only increase the fluorescent intensity but also decrease the particle size of the FND without significant loss of the NV– density. These particles are well suited for bioimaging applications.

並列關鍵字

Fluorescent nanodiamond ； nitrogen content ； bio-labeling

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