title: Highly sensitive color-indicating and quantitative biosensor based on cholesteric liquid crystal.
abstract: Liquid crystal (LC)-based biosensors employ highly sensitive interfaces between the alignment layers and LCs to detect biomolecules and their interactions. Present techniques based on optical texture observation of the homeotropic-to-planar response of nematic LCs are limited by their quantitative reproducibility of results, indicating that both the accuracy and reliability of LC-based detection require further improvements. Here we show that cholesteric LC (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 bovine serum albumin (BSA), a protein standard commonly used in protein quantitation. The color appearance and the corresponding transmission spectrum of the cholesteric phase changed with the concentration of BSA, by which a detection limit of 1 fg/ml was observed. The optical response 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.
authors.affiliation: Institute of Imaging and Biomedical Photonics, College of Photonics, National Chiao Tung University, Guiren Dist., Tainan 71150, Taiwan.
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Hsiao
authors.affiliation: Institute of Imaging and Biomedical Photonics, College of Photonics, National Chiao Tung University, Guiren Dist., Tainan 71150, Taiwan.
authors.forename: Yu-Chien
authors.initials: YC
authors.lastname: Sung
authors.affiliation: Department of Bioscience Technology, Chang Jung Christian University, Guiren Dist., Tainan 71101, Taiwan ; mjlee@mail.cjcu.edu.tw.
authors.forename: Mon-Juan
authors.initials: MJ
authors.lastname: Lee
authors.affiliation: Institute of Imaging and Biomedical Photonics, College of Photonics, National Chiao Tung University, Guiren Dist., Tainan 71150, Taiwan.
authors.forename: Wei
authors.initials: W
authors.lastname: Lee
keywords: (160.1585) Chiral media; (160.3710) Liquid crystals; (170.0170) Medical optics and biotechnology; (230.3720) Liquid-crystal devices