Detail View

 순수 유기 발광 물질은 바이오 이미징, 전자 디스플레이(OLED), 암호화 및 환경 센서 등에 광범위하게 사용되고 있다. 본 연구에서는 아밀로이드 원섬유의 형광 프로브로서 생물학적 분석에 사용되는 Thioflavin T(ThT)의 광발광 특성을 탐구하고, 인광 물질로서의 응용 가치와 저온 환경에서의 검출 능력에 대해 연구하였다. 우리는 상업적으로 이용가능한 유기 염료 분자인 ThT를 사용하여 한 종류의 분자만으로도 분자 형태에 따라 극저온에서 RGB 색상 조정이 가능한 인광 현상에 대해 처음으로 보고하였다. Pristine, protonated, hydroxylated 형태의 ThT 분자는 각각 77 K에서 적색 (615nm), 녹색 (550nm) 및 청색 (460nm)의 가시적인 잔광을 나타내었다. 저렴하면서도 간단한 준비 과정을 통해 RGB 순수 유기 발광체로서 ThT에 대한 새로운 접근이 될 것이다. 또한 알츠하이머 환자의 뇌에서 주로 발견되는 단편 중 베타 아밀로이드 25-35를 표적 물질로 설정하였다. 우리는 pristine ThT가 아밀로이드 원섬유에 결합 되었을 때, 형광과 인광 특성이 모두 10배 증가한다는 것을 발견하였다.

Pure organic luminogens have been extensively used in bioimaging, electronic displays (OLEDs), encryption, and environmental sensors. In this study, we explored the photoluminescence properties of Thioflavin T (ThT) used for biological analysis as a fluorescent probe of amyloid fibril and studied its application value as a phosphorescent material and its detection capability in a low-temperature environment. Here, we report for the first time an RGB color-tunable phosphorescence at cryogenic temperatures based on molecular conformation using single-molecule ThT, a commercially available organic dye molecule. ThT molecules in pristine, protonated, and hydroxylated forms show visible afterglow of red (615 nm), green (550 nm), and blue (460 nm) at 77 K, respectively. It should lead to a new approach to ThT as RGB pure organic phosphor with cost-effective and simple preparation.  Furthermore, beta-amyloid 25-35, a segment mainly found in the brain of Alzheimer’s patients, was set as a target material. We found that pristine ThT was bound to amyloid fibrils and both fluorescence and phosphorescence were increased 10-folds.

Abstract  ⅰ
Table of Contents  ⅲ
List of Figures  ⅴ
1. Introduction  1
 1.1. Pure Organic luminogens  1 
 1.2. Thioflavin T (ThT)  2
 1.3. Amyloid Fibril  6
2. Experimental Section  7
 2.1. Materials  7
 2.2. Sample Preparation  7
  2.2.1. Preparation of ThT Solutions  7
  2.2.2. Formation of Beta-Amyloid Fibril  8
  2.2.3. Thioflavin T Assay  10
 2.3. Measurements  10
  2.3.1. Chemical Analysis Instruments  10
  2.3.2. Optical Analysis Instruments  10
  2.3.3. Other Instruments  11
3. Results and Discussion  12
 3.1. ThT Molecules in Pristine, Protonated and Hydroxylated  Forms  12
  3.1.1. 1H-NMR Spectra Analysis  12
  3.1.2. Raman Spectra Analysis  14
  3.1.3. Geometry Optimized Structure with DFT Calculation  16
  3.1.4. Optical Properties Analysis  18
3.2. ThT Excimers with H+ or OH-	  22
 3.2.1. Fluorescence Spectra of ThT in Aqueous Solution according to Concentration Related to Excimer Formation  22
 3.2.2. 1H-NMR Spectra Analysis  24
 3.2.3. Raman Spectra Analysis  26
 3.2.4. Optical Properties Analysis  28
3.3. Detection Capability to Amyloid Fibril using Various Forms of ThT  31
 3.3.1. Structure and Morphology Analysis of Beta-Amyloid Fibril  31
 3.3.2. Secondary Structure Analysis of Amyloid Fibril/ThT Complex  33
 3.3.3. Photoluminescence Properties Analysis of Amyloid Fibril/ThT Complex  35
4. Conclusions  37
REFERENCES  38