以高分子穩定型液晶膜做為癌症生物標誌CA125之無標記免疫檢測手段

Polymer-Stabilized Liquid Crystal Films for Label-Free Immunodetection of the Cancer Biomarker CA125

段飛帆(Fei-Fan Duan)

指導教授 ： 李偉 ； 李孟娟

國立交通大學/光電學院/影像與生醫光電研究所/碩士(2020年)

摘要

利用液晶作為生醫檢測器之傳感元件相關技術，近年來已逐漸發展成熟，此技術主要是利用生物分子與液晶分子之交互作用，使原先於鍍有垂直配向膜之基板上之液晶的排列順序擾亂，此時於正交偏光顯微鏡下可觀察到光學紋理漏光之訊號，藉此判斷生物分子是否存在。
本研究藉由摻雜高分子聚合物NOA65之液晶作為提升液晶生物感測器靈敏度之手段，再利用影像處理軟體GIMP作為量化生物分子測定之技術。本研究皆使用單片玻璃基板作為液晶生物感測器，使用向列型液晶E7摻雜NOA65曝照UV光前，測定牛血清蛋白濃度低於108 g/ml時，生物分子的數量不足以使原先排列於鍍有垂直配向層玻璃基板上的液晶傾倒，因此無法檢測其訊號，吾人在本研究中優化曝照參數後，進行UV光曝照後，使NOA65進行部分高分子化，發現原先牛血清蛋白濃度低於108 g/ml時所無法檢測之訊號，因此檢測出來，檢測牛血清蛋白之靈敏度提升至109 g/ml，這是由於在液晶中所摻雜NOA65高分子化後之折射率與液晶折射率不匹配所造成的結果，此時在正交光學顯微鏡下，就能觀察出濃度更低的微量生物訊號，此外，吾人使用了本實驗室團隊過去未使用於生物檢測上之液晶AY40-006，此款液晶本身是作為PDLC用之混合液晶，吾人發現使用此款液晶摻雜高分子能使兩材料互溶狀況更佳，較不會出現類似相分離之狀態，且作為傳感元件方面，其感測器靈敏度提升效果也較E7明顯，檢測牛血清蛋白之偵測極限甚至可提升至1013 g/ml.
吾人也將此檢測手段應用到CA-125癌症標記抗原抗體上，將固定濃度的CA-125抗體與不同濃度的CA-125抗原進行免疫複合，可得到CA-125免疫複合體，而能檢測之訊號靈敏度也有所提升，這與檢測牛血清蛋白時所獲得的結果一致，因此在本研究中此檢測手段確實可用作提升生物感測器之靈敏度，未來可針對其它NOA系列的高分子聚合物做測試，驗證是否有相同的現象或是有其它生物檢測方面的突破，而目前檢測手法可以用來檢測更微量或是其它種類之待測物，以利於生物感測器使用之最大化。

關鍵字

生物感測器 ； 高分子穩固型液晶 ； 免疫複合體 ； 癌症標記物CA-125 ； 靈敏度

並列摘要

The technology related to the use of liquid-crystal (LC) as the sensing element of biosensors has gradually matured. This technology mainly uses the interaction between the biomolecules and LCs to disturb the vertical alignment of the LC molecule caused by the alignment layer DMAOP, so that the light leakage signal form the LC’s optical texture can be observed under a cross polarized optical microscope (POM) to confirm the presence of the biomolecules.
In this study, the LC doped with monomer NOA65 was used to improve the sensitivity of biosensors. An image processing software GIMP, was used for quantitative measurement. In this study, the single glass substrate technique was adopted to fabricate the LC biosensor. Before the nematic LC (E7) doped NOA65 was exposed to UV light, the bovine serum albumin (BSA) concentration was less than 108 g/ml cannot be detected, due to the number of biomolecules being too less to disturb the originally vertical-aligned LC molecules. After optimizing the exposure parameters and UV exposure and partially curing the NOA65, It was found that the signal of BSA concentration lower than 108 g/ml can now be detected. Morover, the limit of detection for BSA concentration has increased to 109 g/ml. The results can be explained by the doped polymerized NOA65 having the refractive index that does not match the refractive index of the LC so that, weak biological signals can be observed under a POM. LCs are dumped, so that signals with lower concentrations can be observed under a POM. In addition, LC (AY40-006) which had never been adopted by our research group for biodetection purpose in the past that is mutually soluble with the doped polymer for a hybrid PDLC has been adopted. We found that using AY40-006, as the Solvent, it reduces the chance of phase separation, and as a sensing element, it improves sensitivity of the biosensor. It was found that the signal of BSA concentration lower than 1013 g/ml can now be detected.
We also applied this detection method to demonstrate CA-125 cancer-labeled antigen antibodies. CA-125 immunocomplex can be obtained by immobilizing CA-125 antibodies at a fixed concentration with CA-125 antigens at different concentrations. The signal sensitivity has also been improved, which is consistent with the results obtained when detecting BSA. Therefore, this detection method can indeed be used to improve the sensitivity of the biosensor in this study. The current detection method can be used to detect a smaller amount or other kinds of test objects, in order to maximize the use of biosensors. In the future, it can be tested on other NOA series monomers, to verify whether there is the same phenomenon or other breakthroughs in biodetection.

並列關鍵字

Biosensor ； Polymer stabilized liquid crystal ； immunocomplex ； CA-125 ； sensitivity

參考文獻

參考文獻

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