Label-free, color-indicating, and sensitive biosensors of cholesteric liquid crystals on a single vertically aligned substrate

Fu-Lun Chen; Yu-Jui Fan; Jia-De Lin; Yu-Cheng Hsiao

doi:10.1364/BOE.10.004636

Label-free, color-indicating, and sensitive biosensors of cholesteric liquid crystals on a single vertically aligned substrate

Biomed Opt Express. 2019 Aug 19;10(9):4636-4642. doi: 10.1364/BOE.10.004636. eCollection 2019 Sep 1.

Authors

Fu-Lun Chen^{1

2}, Yu-Jui Fan^{3

4

5}, Jia-De Lin⁶, Yu-Cheng Hsiao^{4

5}

Affiliations

¹ Division of Infectious Diseases, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
² Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
³ School of Biomedical Engineering, Taipei Medical University, 250 Wuxing St., Taipei 11031, Taiwan.
⁴ International PhD Program for Biomedical Engineering, Taipei Medical University, 250 Wuxing St., Taipei 11031, Taiwan.
⁵ Graduate Institute of Biomedical Optomechatronics, Taipei Medical University, 250 Wuxing St., Taipei 11031, Taiwan.
⁶ Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, United Kingdom.

Abstract

Biosensors based on liquid crystal (LC) materials can be made by employing the sensitive interfacial effect between LC molecules and alignment layers on substrates. In the past, the optical texture observation method was used in the LC biosensor field. However, the method is limited by a complicated fabrication process and quantitative reproducibility of results that bv evidence that both the reliability and accuracy of LC biosensors need to be improved. In this report, we demonstrate that cholesteric LC (CLC) cells in which one substrate is coated with a vertically aligned layer can be used as a new sensing technology. The chirality of the single vertically anchored (SVA)/CLC biosensor was tested by detecting bovine serum albumin (BSA), a protein standard commonly used in the lab. The colors and corresponding spectrum of the SVA/CLC biosensor changed with the BSA concentrations. A detection limit of 1 ng/ml was observed for the SVA/CLC biosensor. The linear optical properties of the SVA/CLC biosensor produced cheap, inexpensive, and color-indicating detection of biomolecules, and may promote the technology of point-of-care devices for disease-related biomarker detection.