以單分子螢光光譜研究螢光奈米鑽石在時域上的光物理特性

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Title:	以單分子螢光光譜研究螢光奈米鑽石在時域上的光物理特性
Other Titles:	Time-Domain Study on Photophysical Properties of Fluorescent Nanodiamonds with Single-Molecule Fluorescence Spectroscopy
Authors:	林宗欣
Contributors:	東海大學物理學系行政院國家科學委員會
Date:	2012
Issue Date:	2014-03-07T07:18:53Z (UTC)
Abstract:	?米螢光鑽石呈現出許多卓越的特性，包括在紅外波段有強?的螢光、??光漂白 (photobleaching)及?閃爍、可以很容?地將表面功能性修飾成可與核酸或蛋白質做專一鍵結(specific binding)或非專一鍵結等等。因此，它成為具有多項有?於生物應用特性的新?米材?。此外，?用螢光?米鑽石的色心(color-center)的激發態與細胞的自發螢光比起?有較長的?射生命期(radiative lifetime)的特性，在細胞中的?米鑽石的訊噪比可以藉著?用脈衝?射激發以及時間解析?測?提升。然而，在文獻報導上，螢光?米鑽石的生命期的分布從6 ?秒到30 ?秒。我們先前的實驗結果也發現，隨著?米鑽石的大小的?同，其螢光生命期有很大的差?。到目前，有幾個影響螢光?米鑽石的螢光生命期的原因已經被提出過，包括有效折射?的減少以及在?米鑽石中非規則性的碳排?以及石墨結構的外殼等等。在螢光?米鑽石系綜的光物?特性?測上，通常會遭遇到?個問題。首先是從?米鑽石溶液被散射出?的強激發光常會干擾螢光的?測。其次是在螢光?米鑽石溶液中，事實上還仍然有大??具有色心的非螢光?米鑽石。因此，在對螢光?米鑽石的發光特性做定??測上將會出現困難。所以，在螢光?米鑽石的光物?特性的研究上，單分子螢光的?測是非常重要的。在此工作中，我們將使用單分子螢光光譜的技術，針對螢光?米鑽石的時間解析光物?特性做探討。我們將有系統地對螢光?米鑽石做螢光生命期的?測，以找出造成螢光生命期有極大差?的原因。我們將?用?曼光譜?探討我們的螢光鑽石的結構特性。另外，也將?用螢光相關光譜(FCS)?研究具有較長時間尺?的系間跨越(inter-system crossing)過程。此外，我們也將?用時間解析的特性去研究螢光?米鑽石與??米顆?的交互作用的機制。 Fluorescent nanodiamond (FND) exhibits several remarkable features, including emission of bright photoluminescence in the extended red region, no photobleaching and photoblinking, and easiness of surface functionalization for specific or nonspecific binding with nucleic acids and proteins, etc. Therefore, it is emerging as a new type of nanomaterial that holds great promise for biological applications. Furthermore, the signal-to-noise ratio of FNDs inside the cell can also be improved using a pulsed-excitation laser and time-resolved detection taking advantage of the long radiative lifetime of the color-center excited state as compared to cell autofluorescence. However, in literature, the reported fluorescence lifetime of FNDs ranges from 6 ns to 30 ns. In our previous results, we also got large variations for different sizes of FNDs. Some possible reasons have been proposed, including the decreasing of effective refractive index and disordered-carbon and graphite shell effect. The ensemble measurement of photophysical properties of FNDs usually encounters two problems. First, the strong scattered excitation light from FND solution usually disturbs fluorescence measurement. Second, there are still a lot of nonfluorescent nanodiamonds, in which there is no color-center, in a FND solution. So it is difficult to do quantitative measurement. Therefore, single-molecule measurement is crucial for the investigation of photophysical properties of FNDs. In this work, we will focus on the time-resolved photophysical properties of FNDs using single-molecule fluorescence spectroscopy. We will systematically study the fluorescence lifetime of FNDs to find out the major reasons that cause large variations. Raman spectroscopy will be used to characterize the structure of FNDs. Fluorescence correlation spectroscopy (FCS) will be used to study inter-system crossing processes, which have longer time scale. Furthermore, we will use the time-resolved properties to investigate the mechanism of the interaction between FNDs and gold nanoparticles.
Relation:	計畫編號：NSC99-2112-M029-006-MY3 研究期間：2012-08~ 2013-07
Appears in Collections:	[應用物理學系所] 國科會研究報告

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