糖尿病視網膜病變在現代是失明最主要的原因，如果我們在可以提前診斷並治療可以減緩並降低失明的可能性。現在診斷糖尿病視網膜病變的主要方式為眼底斷層掃描和眼底螢光血管造影，這兩種方式都有一些缺點，眼底斷層掃描需事先使用散瞳劑，這導致生活上暫時的不方便，而眼底螢光血管造影需注射螢光藥劑，這可能會造成部分的人有過敏的症狀，這兩個技術都是需要醫生去做判斷，兩個技術也都造價不斐且不方便的。因此在這個研究中我們想要開發一個可以定量分析的生物感測器來診斷糖尿病視網膜病變，我們的研究是基於光子晶體來增強螢光訊號，並搭配免疫分析法來達到定量分析。根據先前的研究，螢光可以藉由光子晶體的激發(excitation)及提取(extraction)特性來達到數倍的增強。其他研究也指出脂質運載蛋白-1與糖尿病視網膜病變有相關，正常人在眼淚中的脂質運載蛋白-1濃度為1-2 mg/mL，如果患有該疾病濃度會遠超於此，在我們的實驗中，光子晶體結合了免疫分析法，先將捕獲抗體(probe antibody)修飾在光子晶體表面，接著將BSA、抗原、抗體和螢光二級抗體依序接上，再量測其螢光強度。

在這個研究中，我們開發了一個生物感測器，此感測器結合了光子晶體及免疫分析，並搭配微流體系統，讓此裝置可以更簡易的操作。我們先將以修飾抗體的光子晶體黏附在晶片上，藉由重力及毛細力驅使抗原樣品流過光子晶體表面，在這操作中抗體抗原會接枝在表面上，並顯示相對應濃度的螢光亮度。因為相對於在離心管內反應時間較短，相對來說亮度也下降許多，但研究結果顯示在2、10、20 µg/mL組別的螢光亮度分別為42.2、44.8 和 48.9，再組間皆有顯著差異。在上述的表明正常人的淚液脂質運載蛋白-1的濃度為1-2mg/mL，因此可以藉由此特性將淚液樣品稀釋200倍，如患有此疾病螢光亮度將會高於44.8，反之亦然。這項研究提供了一個新穎的光學感測器，該技術有量化、省時且非侵入式，並在不久將可以適用在糖尿病視網膜病變的篩檢。

Diabetic retinopathy (DR) is a major cause of vision loss in the modern time. If the disease is detected in advance, we can pre-treat and start controlling blood glucose level to avoid progressing to serious condition. Nowadays, diagnostic methods have some shortcomings, such as time and resource consuming, technical and non-quantify. In this research, we develop a power-free and simple optical device for detecting biomarker to achieve diagnosis of DR. According to Bragg’s law, wavelength of photonic crystal (PhC) can be predicted by material refraction and particle size. Fluorescence intensity can be enhanced by characteristic of excitation and extraction of PhC. Immunoassay on PhC and feature of PhC accomplished detection. In order to determine DR, Lipocalin 1 (LCN1), one of the biomarkers of DR, was utilized to do the immunoassay. Probe antibody was modified on PhC surface, afterwards, antibody conjugating. BSA, antigen and probe antibody with SAb (SAb) were sequentially conjugated, fluorescence signal is proportional to concentration of LCN1 antigen.

In this research, we developed an innovative biosensor. Gravity and capillary force are used to drive sample to flow over modified PhC, subsequently, immuno-complex will be attached on PhC. Results demonstrate that the intensity in the chip is directly proportional to concentration of LCN1 antigen, and we also found that the intensity in chip is lower than in centrifuge tube, because of lower reaction time. The intensity in control of 2, 10, 20 µg/mL are 40.1, 42.2, 44.8 and 48.9, respectively. It demonstrates that signal between 2 and 10 µg/mL group have significance difference. The tear sample was diluted 200 folds, such dilution reducing the concentration of LCN1 to 5-10μg/mL, 20 µL of diluted tear sample was used to do the detection on chip. The fluorescence signal higher than 44.8 will be diagnosed DR patient. Our results show that the technique possessed advantages of diagnosis of DR for quantification, time-saving and non-invasive diagnosis. The device provided a practical means to achieve power-free analysis. Eventually, this thesis provides a promising optical biosensor for hassle-free DR screening in the near future.

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