光學紋理觀測之外的液晶生醫檢測技術： 垂直錨定膽固醇液晶生醫感測器開發

Abstract

傳統液晶型生醫檢測技術原理為透過液晶分子與生物分子間的交互作用，使液晶分子產生結構排列的破壞，藉由液晶分子之雙折射與散射的光學特性，在正交偏光顯微鏡下可觀察到光學紋理的變化，由此可分檢測出生物分子。然而，就光學紋理法而言，難以作為量化的手段，因此檢測之平台仍有許多進步的空間。本論文以膽固醇型液晶材料作為新型液晶感測器的媒介，藉由膽固醇型液晶之螺旋結構，於不同濃度之生物分子的檢測中，可形成不同的色彩變化，因此突破了光學紋理觀察的缺點。實驗結果顯示，含不同濃度牛血清蛋白之液晶盒可反射不同色彩的可見光，使吾人可以輕易地透過可見光之顏色判斷樣品的濃度差異，且詳細的光譜都可以透過光譜儀作進一步的分析。本研究可測得CA-125免疫複合體之最小濃度極限為1 ng/mL，以此看來膽固醇型液晶用於生醫檢測俱有相當強的潛力。

Liquid crystal (LC)-based biosensors employ highly sensitive interfaces between the alignment layers and LCs to detect biomolecules and their interactions. Present techniques mainly based on optical texture observation which are limited by their quantitative reproducibility of results, indicating that both the accuracy and reliability of LC-based detection require further improvements. In this study we designed that cholesteric liquid crystal (CLC) can be used as a novel sensing element in the design of an alternative LC-based biosensing device. The chirality of the vertically anchored (VA) CLC was exploited in the detection of biomolecules. The color appearance and the corresponding transmission spectrum of the cholesteric phase changed with the concentration of biomolecules, by which a detection limit of 1 ng/mL was observed in CA125 immunodetection. The optical appearance of the VA CLC interface offers a simple and inexpensive platform for highly sensitive and naked-eye color-indicating detection of biomolecules, and, thus, may facilitate the development of point-of-care devices for the detection of disease-related biomarkers.